source: trunk/src/anaToMia/GDL_Widgets/lib/tm.js

// tmjs, version 0.4.0
// http://github.com/jansc/tmjs
// Copyright (c) 2010 Jan Schreiber <jans@ravn.no>
// Licensed under the MIT-License.
//
// Permission is hereby granted, free of charge, to any person
// obtaining a copy of this software and associated documentation
// files (the "Software"), to deal in the Software without
// restriction, including without limitation the rights to use,
// copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following
// conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
// WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
// OTHER DEALINGS IN THE SOFTWARE.
/*jslint browser: true, devel: true, onevar: true, undef: true,
  nomen: false, eqeqeq: true, plusplus: true, bitwise: true,
  regexp: true, newcap: true, immed: true, indent: 4 */
/*global exports*/ 

var TM, TopicMapSystemFactory;

/**
 * @namespace Global namespace that holds all Topic Maps related objects.
 * @author Jan Schreiber <jans@ravn.no>
 * @copyright 2010 Jan Schreiber <http://purl.org/net/jans>
 * Date: Wed Dec 1 08:39:28 2010 +0100
 */
TM = (function () {
    var Version, Hash, XSD, TMDM, Locator, EventType, Topic, Association,
        Scoped, Construct, Typed, Reifiable,
        DatatypeAware, TopicMap, Role, Name,
        Variant, Occurrence, TopicMapSystemMemImpl,
        Index, TypeInstanceIndex, ScopedIndex, 
        SameTopicMapHelper, ArrayHelper, IndexHelper, addScope,
        DuplicateRemover,
        SignatureGenerator, MergeHelper, CopyHelper,
        TypeInstanceHelper;

    Version = '0.4.0';

    // -----------------------------------------------------------------------
    // Our swiss army knife for mixin of functions.
    // See http://javascript.crockford.com/inheritance.html
    Function.prototype.swiss = function (parnt) {
        var i, name;
        for (i = 1; i < arguments.length; i += 1) {
            name = arguments[i];
            this.prototype[name] = parnt.prototype[name];
        }
        return this;
    };

    // -----------------------------------------------------------------------
    // Simple hash table for lookup tables
    Hash = function () {
        this.hash = {};
        this.length = 0;
    };

    /**
     * @class Simple hash implementation.
     */
    Hash.prototype = {
        /**
         * Returns the object belonging to the key key or undefined if the
         * key does not exist.
         * @param key {String} The hash key.
         * @returns {object} The stored object or undefined.
         */        
        get: function (key) {
            return this.hash[key];
        },

        /**
         * Checks if the key exists in the hash table.
         * @param key {String} The hash key.
         * @returns {boolean} True if key exists in the hash table. False
         *          otherwise.
         */
        contains: function (key) {
            return this.get(key) !== undefined;
        },

        /**
         * Stores an object in the hash table.
         * @param key {String} The hash key.
         * @param val {object} The value to be stored in the hash table.
         * @returns val {object} A reference to the stored object.
         */
        put: function (key, val) {
            if (!this.hash[key]) {
                this.length += 1;
            }
            this.hash[key] = val;
            return val;
        },

        /**
         * Removes the key and the corresponding value from the hash table.
         * @param key {String} Removes value corresponding to key and the key
         *             from the hash table
         * @returns {Hash} The hash table itself.
         */
        remove: function (key) {
            delete this.hash[key];
            this.length -= 1;
            return this;
        },

        /**
         * Returns an array with keys of the hash table.
         * @returns {Array} An array with strings.
         */
        keys: function () {
            var ret = [], key;
            for (key in this.hash) {
                if (this.hash.hasOwnProperty(key)) {
                    ret.push(key);
                }
            }
            return ret;
        },

        /**
         * Returns an array with all values of the hash table.
         * @returns {Array} An array with all objects stored as a value in
         *          the hash table.
         */
        values: function () {
            var ret = [], key;
            for (key in this.hash) {
                if (this.hash.hasOwnProperty(key)) {
                    ret.push(this.hash[key]);
                }
            }
            return ret;
        },

        /**
         * Empties the hash table by removing the reference to all objects.
         * Note that the store objects themselves are not touched.
         * @returns undefined
         */
        empty: function () {
            this.hash = {};
            this.length = 0;
        },

        /**
         * Returns the size of the hash table, that is the count of all
         * key/value pairs.
         * @returns {Number} The count of all key/value pairs stored in the
         *          hash table.
         */
        size: function () {
            return this.length;
        }
    };

    // -----------------------------------------------------------------------
    // Internal event handling system
    EventType = {};
    EventType.ADD_ASSOCIATION = 1;
    EventType.ADD_NAME = 2;
    EventType.ADD_OCCURRENCE = 3;
    EventType.ADD_ROLE = 4;
    EventType.ADD_THEME = 5;
    EventType.ADD_TOPIC = 6;
    EventType.ADD_TYPE = 7;
    EventType.REMOVE_ASSOCIATION = 8;
    EventType.REMOVE_NAME = 9;
    EventType.REMOVE_OCCURRENCE = 10;
    EventType.REMOVE_ROLE = 11;
    EventType.REMOVE_THEME = 12;
    EventType.REMOVE_TOPIC = 13;
    EventType.REMOVE_TYPE = 14;
    EventType.SET_TYPE = 15;

    /**
     * @namespace Namespace for XML Schema URIs. // FIXME!!
     */
    XSD = {
        'string': "http://www.w3.org/2001/XMLSchema#string",
        'integer': "http://www.w3.org/2001/XMLSchema#integer",
        'anyURI': "http://www.w3.org/2001/XMLSchema#anyURI"

        // TODO: Add all build-in types
    };

    TMDM = {
        'TYPE_INSTANCE': 'http://psi.topicmaps.org/iso13250/model/type-instance',
        'TYPE': 'http://psi.topicmaps.org/iso13250/model/type',
        'INSTANCE': 'http://psi.topicmaps.org/iso13250/model/instance',
        'TOPIC_NAME': 'http://psi.topicmaps.org/iso13250/model/topic-name'
    };

    // -----------------------------------------------------------------------
    // TODO: The locator functions need some more work. Implement resolve()
    // and toExternalForm()

    /**
     * @class Immutable representation of an IRI.
     */
    Locator = function (parnt, iri) {
        this.parnt = parnt;
        this.iri = iri;
    };

    /**
     * Returns the IRI.
     * @returns {String} A lexical representation of the IRI.
     */
    Locator.prototype.getReference = function () {
        return this.iri;
    };

    /**
     * Returns true if the other object is equal to this one.
     * @param other The object to compare this object against.
     * @returns <code>(other instanceof Locator &&
     *     this.getReference().equals(((Locator)other).getReference()))</code>
     */
    Locator.prototype.equals = function (other) {
        return (this.iri === other.getReference());
    };

    /**
     * Returns the external form of the IRI. Any special character will be
     * escaped using the escaping conventions of RFC 3987.
     * @returns {String} A string representation of this locator suitable for
     * output or passing to APIs which will parse the locator anew.
     */
    Locator.prototype.toExternalForm = function () {
        throw {name: 'NotImplemented', message: 'Locator.toExternalForm() not implemented'};
    };


    // -----------------------------------------------------------------------
    /**
     * @class Represents a Topic Maps construct.
     */
    Construct = function () {};

    /** 
     * Adds an item identifier.
     * @param {Locator} itemIdentifier The item identifier to add.
     * @returns {Construct} The construct itself (for chaining support)
     * @throws {ModelConstraintException} If the itemidentifier is null.
     * @throws {IdentityConstraintException} If another Topic Maps construct with
     *         the same item identifier exists.
     */
    Construct.prototype.addItemIdentifier = function (itemIdentifier) {
        var existing;
        if (itemIdentifier === null) {
            throw {name: 'ModelConstraintException',
            message: 'addItemIdentifier(null) is illegal'};
        }
        existing = this.getTopicMap()._ii2construct.get(itemIdentifier.getReference());
        if (existing) {
            throw {name: 'IdentityConstraintException',
                message: 'Topic Maps constructs with the same item identifier ' +
                        'are not allowed',
                reporter: this,
                existing: existing,
                locator: itemIdentifier};
        }
        this.itemIdentifiers.push(itemIdentifier);
        this.getTopicMap()._ii2construct.put(itemIdentifier.getReference(), this);
        return this;
    };

    /**
     * Returns true if the other object is equal to this one. Equality must be
     * the result of comparing the identity (<code>this == other</code>) of the
     * two objects.
     * Note: This equality test does not reflect any equality rule according to
     * the Topic Maps - Data Model (TMDM) by intention.
     * @param {String} other The object to compare this object against.
     */
    Construct.prototype.equals = function (other) {
        return (this.id === other.id);
    };
    
    /**
     * Returns the identifier of this construct. This property has no
     * representation in the Topic Maps - Data Model.
     *
     * The ID can be anything, so long as no other Construct in the same topic
     * map has the same ID.
     * @returns {String} An identifier which identifies this construct uniquely
     * within a topic map.
     */
    Construct.prototype.getId = function () {
        return this.id;
    };
    
    /**
     * Returns the item identifiers of this Topic Maps construct. The return
     * value may be empty but must never be <code>null</code>.
     * @returns {Array} An array of Locators representing the item identifiers.
     * The array MUST NOT be modified.
     */
    Construct.prototype.getItemIdentifiers = function () {
        return this.itemIdentifiers;
    };
    
    /**
     * Returns the parent of this construct. This method returns
     * <code>null</code> iff this construct is a TopicMap instance.
     * @returns {Construct} The parent of this construct or <code>null</code>
     * iff the construct is an instance of TopicMap.
     */
    Construct.prototype.getParent = function () {
        return this.parnt;
    };
    
    /**
     * Returns the TopicMap instance to which this Topic Maps construct belongs.
     * A TopicMap instance returns itself.
     * @returns {Construct} The topic map instance to which this construct belongs.
     */
    Construct.prototype.getTopicMap = function () {
        throw {name: 'NotImplemented', message: 'getTopicMap() not implemented'};
    };
    
    /**
     * Returns the hash code value.
     * TODO: Is this needed?
     */
    Construct.prototype.hashCode = function () {
        throw {name: 'NotImplemented', message: 'hashCode() not implemented'};
    };
    
    /**
     * Returns the parent of this construct. This method returns
     * <code>null</code> iff this construct is a TopicMap instance.
     * @returns {Construct} The parent of this construct or <code>null</code>
     * iff the construct is an instance of {@link TopicMap}.
     */
    Construct.prototype.remove = function () {
        throw {name: 'NotImplemented', message: 'remove() not implemented'};
    };
    
    /**
     * Removes an item identifier.
     * @param {Locator} itemIdentifier The item identifier to be removed from
     * this construct, if present (<code>null</code> is ignored).
     * @returns {Construct} The construct itself (for chaining support)
     */
    Construct.prototype.removeItemIdentifier = function (itemIdentifier) {
        if (itemIdentifier === null) {
            return;
        }
        for (var i = 0; i < this.itemIdentifiers.length; i += 1) {
            if (this.itemIdentifiers[i].getReference() ===
                    itemIdentifier.getReference()) {
                this.itemIdentifiers.splice(i, 1);
                break;
            }
        }
        this.getTopicMap()._ii2construct.remove(itemIdentifier.getReference());
        return this;
    };
    
    /**
     * Returns true if the construct is a {@link TopicMap}-object
     * @returns <code>true</code> if the construct is a {@link TopicMap}-object,
     *     <code>false</code> otherwise.
     */
    Construct.prototype.isTopicMap = function () {
        return false;
    };
    
    /**
     * Returns true if the construct is a {@link Topic}-object
     * @returns <code>true</code> if the construct is a {@link Topic}-object,
     *     <code>false</code> otherwise.
     */
    Construct.prototype.isTopic = function () {
        return false;
    };
    
    /**
     * Returns true if the construct is an {@link Association}-object
     * @returns <code>true</code> if the construct is an {@link Association}-
     *     object, <code>false</code> otherwise.
     */
    Construct.prototype.isAssociation = function () {
        return false;
    };
    
    /**
     * Returns true if the construct is a {@link Role}-object
     * @returns <code>true</code> if the construct is a {@link Role}-object,
     *     <code>false</code> otherwise.
     */
    Construct.prototype.isRole = function () {
        return false;
    };
    
    /**
     * Returns true if the construct is a {@link Name}-object
     * @returns <code>true</code> if the construct is a {@link Name}-object,
     *     <code>false</code> otherwise.
     */
    Construct.prototype.isName = function () {
        return false;
    };
    
    /**
     * Returns true if the construct is an {@link Occurrenct}-object
     * @returns <code>true</code> if the construct is an {@link Occurrence}-object,
     *     <code>false</code> otherwise.
     */
    Construct.prototype.isOccurrence = function () {
        return false;
    };
    
    /**
     * Returns true if the construct is a {@link Variant}-object
     * @returns <code>true</code> if the construct is a {@link Variant}-object,
     *     <code>false</code> otherwise.
     */
    Construct.prototype.isVariant = function () {
        return false;
    };

    // --------------------------------------------------------------------------
    Typed = function () {};
    
    // Returns the type of this construct.
    Typed.prototype.getType = function () {
        return this.type;
    };
    
    /**
     * Sets the type of this construct.
     * @throws {ModelConstraintException} If type is null.
     * @returns {Typed} The type itself (for chaining support)
     */
    Typed.prototype.setType = function (type) {
        if (type === null) {
            throw {name: 'ModelConstraintException',
            message: 'Topic.setType cannot be called without type'};
        }
        SameTopicMapHelper.assertBelongsTo(this.getTopicMap(), type);
        this.getTopicMap().setTypeEvent.fire(this, {old: this.type, type: type});
        this.type = type;
        return this;
    };
    
    // --------------------------------------------------------------------------
    /**
     * @class Indicates that a statement (Topic Maps construct) has a scope.
     * Associations, Occurrences, Names, and Variants are scoped.
     */
    Scoped = function () {};
    
    /**
     * Adds a topic to the scope.
     * @throws {ModelConstraintException} If theme is null.
     * @returns {Typed} The type itself (for chaining support)
     */
    Scoped.prototype.addTheme = function (theme) {
        if (theme === null) {
            throw {name: 'ModelConstraintException',
            message: 'addTheme(null) is illegal'}; 
        }
        // Check if theme is part of the scope
        for (var i = 0; i < this.scope.length; i += 1) {
            if (this.scope[i] === theme) {
                return false;
            }
        }
        SameTopicMapHelper.assertBelongsTo(this.getTopicMap(), theme);
        this.scope.push(theme);
        this.getTopicMap().addThemeEvent.fire(this, {theme: theme});
        // Special case for names: add the theme to all variants
        if (this.isName()) {
            for (i = 0; i < this.variants.length; i += 1) {
                this.getTopicMap().addThemeEvent.fire(this.variants[i], {theme: theme});
            }
        }
        return this;
    };
    
    /**
     * Returns the topics which define the scope.
     * @returns {Array} A possible empty Array with Topic objects.
     */
    Scoped.prototype.getScope = function () {
        if (this.isVariant()) {
            var i, tmp = new Hash(), parent_scope = this.parnt.getScope();
            for (i = 0; i < parent_scope.length; i += 1) {
                tmp.put(parent_scope[i].getId(), parent_scope[i]);
            }
            for (i = 0; i < this.scope.length; i += 1) {
                tmp.put(this.scope[i].getId(), this.scope[i]);
            }
            return tmp.values();
        }
        return this.scope;
    };
    
    /**
     * Removes a topic from the scope. 
     * @returns {Scoped} The scoped object itself (for chaining support)
     */
    Scoped.prototype.removeTheme = function (theme) {
        var i, j, scope, found;
        for (i = 0; i < this.scope.length; i += 1) {
            if (this.scope[i] === theme) {
                this.getTopicMap().removeThemeEvent.fire(this, {theme: this.scope[i]});
                this.scope.splice(i, 1);
                break;
            }
        }
        // Special case for names: remove the theme from index for all variants
        if (this.isName()) {
            for (i = 0; i < this.variants.length; i += 1) {
                scope = this.variants[i].scope;
                // Check if the the variant has theme as scope
                found = false;
                for (j = 0; j < scope.length; j += 1) {
                    if (theme.equals(scope[j])) {
                        found = true;
                    }
                }
                if (!found) {
                    this.getTopicMap().removeThemeEvent.fire(this.variants[i], {theme: theme});
                }
            }
        }
        return this;
    };
    
    
    // --------------------------------------------------------------------------
    /**
     * @class Indicates that a Construct is reifiable. Every Topic Maps
     * construct that is not a Topic is reifiable.
     */
    Reifiable = function () {};
    
    /**
     * Returns the reifier of this construct.
     */
    Reifiable.prototype.getReifier = function () {
        return this.reifier;
    };
    
    /**
     * Sets the reifier of the construct.
     * @throws {ModelConstraintException} If reifier already reifies another
     * construct.
     * @returns {Reifiable} The reified object itself (for chaining support)
     */
    Reifiable.prototype.setReifier = function (reifier) {
        if (reifier && reifier.getReified() !== null) {
            throw {name: 'ModelConstraintException',
                message: 'Reifies already another construct'};
        }
        SameTopicMapHelper.assertBelongsTo(this.getTopicMap(), reifier);
        if (this.reifier) {
            this.reifier._setReified(null);
        }
        if (reifier) {
            reifier._setReified(this);
        }
        this.reifier = reifier;
        return this;
    };
    
    // --------------------------------------------------------------------------
    /**
     * @class Common base interface for Occurrences and Variants.
     * Inherits Scoped, Reifiable
     */
    DatatypeAware = function () {};
    
    /**
     * Returns the BigDecimal representation of the value.
     */
    DatatypeAware.prototype.decimalValue = function () {
        // FIXME Implement!
    };
    
    /**
     * Returns the float representation of the value.
     * @throws {NumberFormatException} If the value is not convertable to float.
     */
    DatatypeAware.prototype.floatValue = function () {
        var ret = parseFloat(this.value);
        if (isNaN(ret)) {
            throw {name: 'NumberFormatException',
                message: '"' + this.value + '" is not a float'};
        }
        return ret;
    };
    
    /**
     * Returns the Locator identifying the datatype of the value.
     */
    DatatypeAware.prototype.getDatatype = function () {
        return this.datatype;
    };
    
    /**
     * Returns the lexical representation of the value.
     */
    DatatypeAware.prototype.getValue = function () {
        if (typeof this.value === 'object' && this.value instanceof Locator) {
            return this.value.getReference();
        }
        return this.value.toString();
    };
    
    /**
     * Returns the BigInteger representation of the value.
     * @throws {NumberFormatException} If the value cannot be parsed as an int.
     */
    DatatypeAware.prototype.integerValue = function () {
        var ret = parseInt(this.value, 10);
        if (isNaN(ret)) {
            throw {name: 'NumberFormatException',
                message: '"' + this.value + '" is not an integer'};
        }
        return ret;
    };
    
    /**
     * Returns the Locator representation of the value.
     * @throws {ModelConstraintException} If the value is not an Locator
     * object.
     */
    DatatypeAware.prototype.locatorValue = function () {
        if (!(typeof this.value === 'object' && this.value instanceof Locator)) {
            throw {name: 'ModelConstraintException',
                message: '"' + this.value + '" is not a locator'};
        }
        return this.value;
    };
    
    /**
     * Returns the long representation of the value.
     */
    DatatypeAware.prototype.longValue = function () {
        // FIXME Implement!
    };
    
    /**
     * Sets the value and the datatype.
     * @throws {ModelConstraintException} If datatype or value is null.
     */
    DatatypeAware.prototype.setValue = function (value, datatype) {
        var tm = this.getTopicMap();
        if (datatype === null) {
            throw {name: 'ModelConstraintException', message: 'Invalid datatype'};
        }
        if (value === null) {
            throw {name: 'ModelConstraintException', message: 'Invalid value'};
        }
        this.value = value;
        this.datatype = datatype ||
            this.getTopicMap().createLocator(XSD.string);
        if (datatype && datatype.getReference() === XSD.anyURI) {
            this.value = tm.createLocator(value);
        }
        if (!datatype) {
            if (typeof value === 'number') {
                // FIXME Could be XSD.float as well
                this.datatype = tm.createLocator(XSD.integer);
            }
        }
        if (typeof value === 'object' && value instanceof Locator) {
            this.datatype = tm.createLocator(XSD.anyURI);
        }
    };
    
    // --------------------------------------------------------------------------
    /**
     * Constructs a new Topic Map System Factoy. The constructor should not be
     * called directly. Use the {TM.TopicMapSystemFactory.newInstance} instead.
     * @class Represents a Topic Maps construct.
     * @memberOf TM
     */
    TopicMapSystemFactory = function () {
        this.properties = {};
        this.features = {};
    };
    
    /**
     * Returns the particular feature requested for in the underlying implementation
     * of TopicMapSystem.
     */
    TopicMapSystemFactory.prototype.getFeature = function (featureName) {
        return this.features;
    };
    
    /**
     * Gets the value of a property in the underlying implementation of
     * TopicMapSystem.
     */
    TopicMapSystemFactory.prototype.getProperty = function (propertyName) {
        return this.properties[propertyName];
    };
    
    /**
     * Returns if the particular feature is supported by the TopicMapSystem.
     */
    TopicMapSystemFactory.prototype.hasFeature = function (featureName) {
        return false;
    };
    
    /**
     * Obtain a new instance of a TopicMapSystemFactory.
     * @static
     * @returns {TopicMapSystemFactory}
     */
    TopicMapSystemFactory.newInstance = function () {
        return new TopicMapSystemFactory();
    };
    
    /**
     * Creates a new TopicMapSystem instance using the currently configured
     * factory parameters.
     */
    TopicMapSystemFactory.prototype.newTopicMapSystem = function () {
        var backend = this.properties['com.semanticheadache.tmjs.backend'] || 'memory'; 
        if (backend === 'memory') {
            return new TopicMapSystemMemImpl();
        }
    };
    
    /**
     * Sets a particular feature in the underlying implementation of TopicMapSystem.
     */
    TopicMapSystemFactory.prototype.setFeature = function (featureName, enable) {
        this.features[featureName] = enable;
    };
    
    /**
     * Sets a property in the underlying implementation of TopicMapSystem.
     */
    TopicMapSystemFactory.prototype.setProperty = function (propertyName, value) {
        this.properties[propertyName] = value;
    };
    
    /**
     * Creates a new instance of TopicMamSystem.
     * @class Implementation of the TopicMapSystem interface.
     */
    TopicMapSystemMemImpl = function () {
        this.topicmaps = {};
    };
    
    /**
     * @throws {TopicMapExistsException} If a topic map with the given locator
     * already exists.
     */
    TopicMapSystemMemImpl.prototype.createTopicMap = function (locator) {
        if (this.topicmaps[locator.getReference()]) {
            throw {name: 'TopicMapExistsException',
                message: 'A topic map under the same IRI already exists'};
        }
        var tm = new TopicMap(this, locator);
        this.topicmaps[locator.getReference()] = tm;
        return tm;
    };
    
    TopicMapSystemMemImpl.prototype.getLocators = function () {
        var locators = [], key;
        for (key in this.topicmaps) {
            if (this.topicmaps.hasOwnProperty(key)) {
                locators.push(this.createLocator(key));
            }
        }
        return locators;
    };
    
    TopicMapSystemMemImpl.prototype.getTopicMap = function (locator) {
        var tm;
        if (locator instanceof Locator) {
            tm = this.topicmaps[locator.getReference()];
        } else {
            tm = this.topicmaps[locator];
        }
        if (!tm) {
            return null;
        }
        return tm;
    };
    
    /**
     * @param {String} iri
     */
    TopicMapSystemMemImpl.prototype.createLocator = function (iri) {
        return new Locator(this, iri);
    };
    
    TopicMapSystemMemImpl.prototype.getFeature = function (featureName) {
        return false;
    };
    
    TopicMapSystemMemImpl.prototype._removeTopicMap = function (tm) {
        var key;
        for (key in this.topicmaps) {
            if (this.topicmaps.hasOwnProperty(key) &&
                key === tm.locator.getReference()) {
                delete this.topicmaps[key];
            }
        }
    };
    
    TopicMapSystemMemImpl.prototype.close = function () {
        this.topicmaps = null; // release references
    };
    
    TopicMap = function (tms, locator) {
        this.topicmapsystem = tms;
        this.itemIdentifiers = [];
        this.locator = locator;
        this.topics = [];
        this.associations = [];
        this._constructId = 1;
        this._si2topic = new Hash(); // Index for subject identifiers
        this._sl2topic = new Hash(); // Index for subject locators
        this._ii2construct = new Hash(); // Index for item identifiers
        this._id2construct = new Hash(); // Index for object ids

        // The topic map object always get the id 0
        this.id = 0;
        this._id2construct.put(this.id, this);

        this.reifier = null;
        this.handlers = [];

        // Our own event handling mechanism
        var EventHandler = function (eventtype) {
            this.eventtype = eventtype;
            this.handlers = [];
        };
        EventHandler.prototype = {
            registerHandler: function (handler) {
                this.handlers.push(handler);
            },
            removeHandler: function (handler) {
                for (var i = 0; i < this.handlers.length; i += 1) {
                    if (handler.toString() ===
                        this.handlers[i].toString()) {
                        this.handlers.splice(i, 1);
                    }
                }
            },
            fire: function (source, obj) {
                obj = obj || {};
                for (var i = 0; i < this.handlers.length; i += 1) {
                    this.handlers[i](this.eventtype, source, obj);
                }
            }
        };
        this.addAssociationEvent = new EventHandler(EventType.ADD_ASSOCIATION); 
        this.addNameEvent = new EventHandler(EventType.ADD_NAME); 
        this.addOccurrenceEvent = new EventHandler(EventType.ADD_OCCURRENCE); 
        this.addRoleEvent = new EventHandler(EventType.ADD_ROLE); 
        this.addThemeEvent = new EventHandler(EventType.ADD_THEME); 
        this.addTopicEvent = new EventHandler(EventType.ADD_TOPIC); 
        this.addTypeEvent = new EventHandler(EventType.ADD_TYPE); 
        this.removeAssociationEvent = new EventHandler(EventType.REMOVE_ASSOCIATION);
        this.removeNameEvent = new EventHandler(EventType.REMOVE_NAME);
        this.removeOccurrenceEvent = new EventHandler(EventType.REMOVE_OCCURRENCE);
        this.removeRoleEvent = new EventHandler(EventType.REMOVE_ROLE);
        this.removeThemeEvent = new EventHandler(EventType.REMOVE_THEME);
        this.removeTopicEvent = new EventHandler(EventType.REMOVE_TOPIC);
        this.removeTypeEvent = new EventHandler(EventType.REMOVE_TYPE); 
        this.setTypeEvent = new EventHandler(EventType.SET_TYPE);
        this.typeInstanceIndex = new TypeInstanceIndex(this);
        this.scopedIndex = new ScopedIndex(this);
    };

    /**
     * @returns {TopicMap} The topic map object itself (for chaining support)
     */
    TopicMap.prototype.register_event_handler = function (type, handler) {
        switch (type) {
        case EventType.ADD_ASSOCIATION:
            this.addAssociationEvent.registerHandler(handler);
            break;
        case EventType.ADD_NAME:
            this.addNameEvent.registerHandler(handler);
            break;
        case EventType.ADD_OCCURRENCE:
            this.addOccurrenceEvent.registerHandler(handler);
            break;
        case EventType.ADD_ROLE:
            this.addRoleEvent.registerHandler(handler);
            break;
        case EventType.ADD_THEME:
            this.addThemeEvent.registerHandler(handler);
            break;
        case EventType.ADD_TOPIC:
            this.addTopicEvent.registerHandler(handler);
            break;
        case EventType.ADD_TYPE:
            this.addTypeEvent.registerHandler(handler);
            break;
        case EventType.REMOVE_ASSOCIATION:
            this.removeAssociationEvent.registerHandler(handler);
            break;
        case EventType.REMOVE_NAME:
            this.removeNameEvent.registerHandler(handler);
            break;
        case EventType.REMOVE_OCCURRENCE:
            this.removeOccurrenceEvent.registerHandler(handler);
            break;
        case EventType.REMOVE_ROLE:
            this.removeRoleEvent.registerHandler(handler);
            break;
        case EventType.REMOVE_THEME:
            this.removeThemeEvent.registerHandler(handler);
            break;
        case EventType.REMOVE_TOPIC:
            this.removeTopicEvent.registerHandler(handler);
            break;
        case EventType.REMOVE_TYPE:
            this.removeTypeEvent.registerHandler(handler);
            break;
        case EventType.SET_TYPE:
            this.setTypeEvent.registerHandler(handler);
            break;
        }
        return this;
    };

    TopicMap.swiss(Reifiable, 'getReifier', 'setReifier');
    TopicMap.swiss(Construct, 'addItemIdentifier', 'getItemIdentifiers',
        'removeItemIdentifier', 'isTopic', 'isAssociation', 'isRole',
        'isOccurrence', 'isName', 'isVariant', 'isTopicMap');
    /**
     * Removes duplicate topic map objects. This function is quite expensive,
     * so it should not be called too often. It is meant to remove duplicates
     * after imports of topic maps.
     * @returns {TopicMap} The topic map object itself (for chaining support)
     */
    TopicMap.prototype.sanitize = function () {
        DuplicateRemover.removeTopicMapDuplicates(this);
        TypeInstanceHelper.convertAssociationsToType(this);
        return this;
    };
    
    TopicMap.prototype.isTopicMap = function () {
        return true;
    };
    
    TopicMap.prototype._getConstructId = function () {
        this._constructId = this._constructId + 1;
        return this._constructId;
    };
    
    TopicMap.prototype.remove = function () {
        if (this.topicmapsystem === null) {
            return null;
        }
        this.topicmapsystem._removeTopicMap(this);
        this.topicmapsystem = null;
        this.itemIdentifiers = null;
        this.locator = null;
        this.topics = null;
        this.associations = null;
        this._si2topic = null;
        this._sl2topic = null;
        this._ii2construct = null;
        this._id2construct = null;
        this.reifier = null;
        this.id = null;
        this.typeInstanceIndex = null;
        return null;
    };
    
    /**
     * @throws {ModelConstraintException} If type or scope is null.
     */
    TopicMap.prototype.createAssociation = function (type, scope) {
        var a;
        if (type === null) {
            throw {name: 'ModelConstraintException',
                message: 'Creating an association with type == null is not allowed'};
        } 
        if (scope === null) {
            throw {name: 'ModelConstraintException',
                message: 'Creating an association with scope == null is not allowed'};
        }
        SameTopicMapHelper.assertBelongsTo(this, type);
        SameTopicMapHelper.assertBelongsTo(this, scope);
    
        a = new Association(this);
        this.associations.push(a);
        if (type) {
            a.setType(type);
        }
        addScope(a, scope);
        this.addAssociationEvent.fire(a);
        return a;
    };
    
    TopicMap.prototype.createLocator = function (iri) {
        return new Locator(this, iri);
    };
    
    TopicMap.prototype._createEmptyTopic = function () {
        var t = new Topic(this);
        this.addTopicEvent.fire(t);
        this.topics.push(t);
        return t;
    };
    
    TopicMap.prototype.createTopic = function () {
        var t = this._createEmptyTopic();
        t.addItemIdentifier(this.createLocator('urn:x-tmjs:' + t.getId()));
        return t;
    };
    
    /**
     * @throws {ModelConstraintException} If no itemIdentifier is given.
     * @throws {IdentityConstraintException} If another construct with the
     * specified item identifier exists which is not a Topic.
     */
    TopicMap.prototype.createTopicByItemIdentifier = function (itemIdentifier) {
        if (!itemIdentifier) {
            throw {name: 'ModelConstraintException',
            message: 'createTopicByItemIdentifier() needs an item identifier'};
        }
        var t = this.getConstructByItemIdentifier(itemIdentifier);
        if (t) {
            if (!t.isTopic()) {
                throw {name: 'IdentityConstraintException',
                message: 'Another construct with the specified item identifier ' +
                    'exists which is not a Topic.'};
            }
            return t;
        }
        t = this._createEmptyTopic();
        t.addItemIdentifier(itemIdentifier);
        return t;
    };
    
    /**
     * @throws {ModelConstraintException} If no subjectIdentifier is given.
     */
    TopicMap.prototype.createTopicBySubjectIdentifier = function (subjectIdentifier) {
        if (!subjectIdentifier) {
            throw {name: 'ModelConstraintException',
            message: 'createTopicBySubjectIdentifier() needs a subject identifier'};
        }
        var t = this.getTopicBySubjectIdentifier(subjectIdentifier);
        if (t) {
            return t;
        }
        t = this._createEmptyTopic();
        t.addSubjectIdentifier(subjectIdentifier);
        return t;
    };
    
    /**
     * @throws {ModelConstraintException} If no subjectLocator is given.
     */
    TopicMap.prototype.createTopicBySubjectLocator = function (subjectLocator) {
        if (!subjectLocator) {
            throw {name: 'ModelConstraintException',
            message: 'createTopicBySubjectLocator() needs a subject locator'};
        }
        var t = this.getTopicBySubjectLocator(subjectLocator);
        if (t) {
            return t;
        }
        t = this._createEmptyTopic();
        t.addSubjectLocator(subjectLocator);
        return t;
    };
    
    TopicMap.prototype.getAssociations = function () {
        return this.associations;
    };
    
    /**
     * @throws {ModelConstraintException} If id is null.
     */
    TopicMap.prototype.getConstructById = function (id) {
        if (id === null) {
            throw {name: 'ModelConstraintException',
                message: 'getConstructById(null) is illegal'};
        }
        var ret = this._id2construct.get(id);
        if (!ret) {
            return null;
        }
        return ret;
    };
    
    /**
     * @throws {ModelConstraintException} If itemIdentifier is null.
     */
    TopicMap.prototype.getConstructByItemIdentifier = function (itemIdentifier) {
        if (itemIdentifier === null) {
            throw {name: 'ModelConstraintException',
                message: 'getConstructByItemIdentifier(null) is illegal'};
        }
        var ret = this._ii2construct.get(itemIdentifier.getReference());
        if (!ret) {
            return null;
        }
        return ret;
    };
    
    /**
     * @throws {UnsupportedOperationException} If the index type is not
     * supported.
     */
    TopicMap.prototype.getIndex = function (className) {
        var index;
        if (className === 'TypeInstanceIndex') {
            index = this.typeInstanceIndex;
            return index;
        } else if (className === 'ScopedIndex') {
            index = new ScopedIndex(this);
            return index;
        }
        // TODO: Should we throw an exception that indicates that the 
        // index is not known? Check the TMAPI docs!
        throw {name: 'UnsupportedOperationException', 
            message: 'getIndex ist not (yet) supported'};
    };
    
    TopicMap.prototype.getParent = function () {
        return null;
    };
    
    TopicMap.prototype.getTopicBySubjectIdentifier = function (subjectIdentifier) {
        var res = this._si2topic.get(subjectIdentifier.getReference());
        if (res) {
            return res;
        }
        return null; // Make sure that the result is not undefined
    };
    
    TopicMap.prototype.getTopicBySubjectLocator = function (subjectLocator) {
        var res = this._sl2topic.get(subjectLocator.getReference());
        if (res) {
            return res;
        }
        return null; // Make sure that the result is not undefined
    };
    
    TopicMap.prototype.getLocator = function () {
        return this.locator;
    };
    
    TopicMap.prototype.getTopics = function () {
        return this.topics;
    };
    
    TopicMap.prototype.mergeIn = function (topicmap) {
        // TODO implement!
        throw {name: 'NotImplemented', message: 'TopicMap.mergeIn() not implemented'};
    };
    
    TopicMap.prototype.equals = function (topicmap) {
        return this.locator.equals(topicmap.locator);
    };
    
    TopicMap.prototype.getId = function () {
        return this.id;
    };
    
    TopicMap.prototype.getTopicMap = function () {
        return this;
    };
    
    // Remove item identifiers
    TopicMap.prototype._removeConstruct = function (construct) {
        var iis = construct.getItemIdentifiers(), i;
        for (i = 0; i < iis.length; i += 1) {
            this._ii2construct.remove(iis[i].getReference());
        }
        this._id2construct.remove(construct.getId());
    };
    
    TopicMap.prototype._removeTopic = function (topic) {
        var i, sis = topic.getSubjectIdentifiers(),
            slos = topic.getSubjectLocators();
        // remove subject identifiers from TopicMap._si2topic
        for (i = 0; i < sis.length; i += 1) {
            this._si2topic.remove(sis[i].getReference());
        }
        // remove subject locators from TopicMap._sl2topic
        for (i = 0; i < slos.length; i += 1) {
            this._sl2topic.remove(slos[i].getReference());
        }
        this._removeConstruct(topic);
        // remove topic from TopicMap.topics
        for (i = 0; i < this.topics.length; i += 1) {
            if (topic.id === this.topics[i].id) {
                this.topics.splice(i, 1);
                break;
            }
        }
    };
    
    TopicMap.prototype._removeAssociation = function (association) {
        var i;
        // remove association from TopicMap.associations
        for (i = 0; i < this.associations.length; i += 1) {
            if (association.id === this.associations[i].id) {
                this.associations.splice(i, 1);
                break;
            }
        }
        this._removeConstruct(association);
        // remove association from TopicMap.associations
        for (i = 0; i < this.associations.length; i += 1) {
            if (association.id === this.associations[i].id) {
                this.associations.splice(i, 1);
                break;
            }
        }
    };
    
    TopicMap.prototype._removeRole = function (role) {
        this._removeConstruct(role);
    };
    
    TopicMap.prototype._removeOccurrence = function (occ) {
        this._removeConstruct(occ);
    };
    
    TopicMap.prototype._removeName = function (name) {
        this._removeConstruct(name);
    };
    
    TopicMap.prototype._removeVariant = function (variant) {
        this._removeConstruct(variant);
    };
    
    // hashCode, remove
    
    // --------------------------------------------------------------------------
    
    Topic = function (parnt) {
        this.subjectIdentifiers = [];
        this.subjectLocators = [];
        this.itemIdentifiers = [];
        this.parnt = parnt;
        this.id = parnt._getConstructId();
        this.getTopicMap()._id2construct.put(this.id, this);
        this.types = [];
        this.rolesPlayed = [];
        this.occurrences = [];
        this.names = [];
        this.reified = null;
    };
    
    Topic.swiss(Construct, 'addItemIdentifier', 'equals', 'getId',
        'getItemIdentifiers', 'getParent', 'getTopicMap', 'hashCode', 'remove',
        'removeItemIdentifier', 'isTopic', 'isAssociation', 'isRole',
        'isOccurrence', 'isName', 'isVariant', 'isTopicMap');
    
    Topic.prototype.isTopic = function () {
        return true;
    };
    
    Topic.prototype.getTopicMap = function () {
        return this.parnt;
    };
    
    /**
     * Adds a subject identifier to this topic.
     * @throws {ModelConstraintException} If subjectIdentifier is null or
     * not defined.
     * @returns {Topic} The topic itself (for chaining support)
     */
    Topic.prototype.addSubjectIdentifier = function (subjectIdentifier) {
        if (!subjectIdentifier) {
            throw {name: 'ModelConstraintException',
            message: 'addSubjectIdentifier() needs subject identifier'};
        }
        // Ignore if the identifier already exists
        for (var i = 0; i < this.subjectIdentifiers.length; i += 1) {
            if (this.subjectIdentifiers[i].getReference() ===
                subjectIdentifier.getReference()) {
                return;
            }
        }
        this.subjectIdentifiers.push(subjectIdentifier);
        this.parnt._si2topic.put(subjectIdentifier.getReference(), this);
        return this;
    };
    
    /**
     * Adds a subject locator to this topic.
     * @throws {ModelConstraintException} If subjectLocator is null or
     * not defined.
     * @returns {Topic} The topic itself (for chaining support)
     */
    Topic.prototype.addSubjectLocator = function (subjectLocator) {
        if (!subjectLocator) {
            throw {name: 'ModelConstraintException',
            message: 'addSubjectLocator() needs subject locator'};
        }
        // Ignore if the identifier already exists
        for (var i = 0; i < this.subjectLocators.length; i += 1) {
            if (this.subjectLocators[i].getReference() ===
                subjectLocator.getReference()) {
                return;
            }
        }
        this.subjectLocators.push(subjectLocator);
        this.parnt._sl2topic.put(subjectLocator.getReference(), this);
        return this;
    };
    
    /**
     * Adds a type to this topic.
     * @throws {ModelConstraintException} If type is null or not defined.
     * @returns {Topic} The topic itself (for chaining support)
     */
    Topic.prototype.addType = function (type) {
        if (!type) {
            throw {name: 'ModelConstraintException',
            message: 'addType() needs type'};
        }
        SameTopicMapHelper.assertBelongsTo(this.parnt, type);
        this.parnt.addTypeEvent.fire(this, {type: type});
        this.types.push(type);
        return this;
    };
    
    // TODO: @type is optional In TMAPI 2.0
    // Creates a Name for this topic with the specified value, and scope.
    // Creates a Name for this topic with the specified type, value, and scope.
    Topic.prototype.createName = function (value, type, scope) {
        var name;
        if (type) {
            SameTopicMapHelper.assertBelongsTo(this.parnt, type);
        }
        if (scope) {
            SameTopicMapHelper.assertBelongsTo(this.parnt, scope);
        }
        if (typeof scope === 'undefined') {
            scope = null;
        }
    
        name = new Name(this, value, type);
        addScope(name, scope);
        this.names.push(name);
        return name;
    };
    
    // TODO: @datatype is optional in TMAPI, value may be string or locator.
    // Creates an Occurrence for this topic with the specified type, IRI value, and
    // scope.
    // createOccurrence(Topic type, java.lang.String value, Locator datatype,
    // java.util.Collection<Topic> scope) 
    // Creates an Occurrence for this topic with the specified type, string value,
    // and scope.
    Topic.prototype.createOccurrence = function (type, value, datatype, scope) {
        var occ;
        SameTopicMapHelper.assertBelongsTo(this.parnt, type);
        SameTopicMapHelper.assertBelongsTo(this.parnt, scope);
    
        occ = new Occurrence(this, type, value, datatype);
        this.parnt.addOccurrenceEvent.fire(occ, {type: type, value: value});
        addScope(occ, scope);
        this.occurrences.push(occ);
        return occ;
    };
    
    /**
     * Returns the Names of this topic where the name type is type.
     *type is optional.
     */
    Topic.prototype.getNames = function (type) {
        var ret = [], i;

        for (i = 0; i < this.names.length; i += 1) {
            if (type && this.names[i].getType().equals(type)) {
                ret.push(this.names[i]);
            } else if (!type) {
                ret.push(this.names[i]);
            }
        }
        return ret;
    };
    
    /**
     * Returns the Occurrences of this topic where the occurrence type is type. type
     * is optional.
     * @throws {IllegalArgumentException} If type is null.
     */
    Topic.prototype.getOccurrences = function (type) {
        var ret = [], i;
        if (type === null) {
            throw {name: 'IllegalArgumentException',
                message: 'Topic.getOccurrences cannot be called without type'};
        }
        for (i = 0; i < this.occurrences.length; i += 1) {
            if (type && this.occurrences[i].getType().equals(type)) {
                ret.push(this.occurrences[i]);
            } else if (!type) {
                ret.push(this.occurrences[i]);
            }
        }
        return ret;
    };
    
    Topic.prototype._removeOccurrence = function (occ) {
        // remove this from TopicMap.topics
        for (var i = 0; i < this.occurrences.length; i += 1) {
            if (this.occurrences[i].equals(occ)) {
                this.occurrences.splice(i, 1);
                break;
            }
        }
        this.getTopicMap()._removeOccurrence(occ);
    };
    
    // Returns the Construct which is reified by this topic.
    Topic.prototype.getReified = function (type) {
        return this.reified;
    };
    
    Topic.prototype._setReified = function (reified) {
        this.reified = reified;
    };
    
    /**
     * Returns the roles played by this topic.
     * Returns the roles played by this topic where the role type is type.
     * assocType is optional
     * @throws {IllegalArgumentException} If type or assocType is null.
     */
    Topic.prototype.getRolesPlayed = function (type, assocType) {
        if (type === null) {
            throw {name: 'IllegalArgumentException',
                message: 'Topic.getRolesPlayed cannot be called without type'};
        }
        if (assocType === null) {
            throw {name: 'IllegalArgumentException',
                message: 'Topic.getRolesPlayed cannot be called with assocType===null'};
        }
        var ret = [], i;
        for (i = 0; i < this.rolesPlayed.length; i += 1) {
            if (!type) {
                ret.push(this.rolesPlayed[i]);
            } else if (this.rolesPlayed[i].getType().equals(type)) {
                if (assocType &&
                    this.rolesPlayed[i].getParent().getType().equals(assocType) ||
                    !assocType) {
                    ret.push(this.rolesPlayed[i]);
                }
            }
        }
        return ret;
    };
    
    // @private Registers role as a role played
    // TODO: Rename to _addRolePlayed
    Topic.prototype.addRolePlayed = function (role) {
        this.rolesPlayed.push(role);
    };
    
    // TODO: Rename to _removeRolePlayed
    Topic.prototype.removeRolePlayed = function (role) {
        for (var i = 0; i < this.rolesPlayed.length; i += 1) {
            if (this.rolesPlayed[i].id === role.id) {
                this.rolesPlayed.splice(i, 1);
            }
        }
    };
    
    /**
     * Returns the subject identifiers assigned to this topic.
     */
    Topic.prototype.getSubjectIdentifiers = function () {
        return this.subjectIdentifiers;
    };
    
    /**
     * Returns the subject locators assigned to this topic.
     */
    Topic.prototype.getSubjectLocators = function () {
        return this.subjectLocators;
    };
    
    /**
     * Returns the types of which this topic is an instance of.
     */
    Topic.prototype.getTypes = function () {
        return this.types;
    };
    
    /**
     * Merges another topic into this topic.
     * @throws {ModelConstraintException} If the topics reify different
     * information items.
     * @returns {Topic} The topic itself (for chaining support)
     */
    Topic.prototype.mergeIn = function (other) {
        var arr, i, tmp, tmp2, signatures, tiidx, sidx;
        if (this.equals(other)) {
            return true;
        }

        SameTopicMapHelper.assertBelongsTo(this.getTopicMap(), other);
        if (this.getReified() && other.getReified() &&
            !this.getReified().equals(other.getReified())) {
            throw {name: 'ModelConstraintException',
                message: 'The topics reify different Topic Maps constructs and cannot be merged!'
            };
        }

        if (!this.getReified() && other.getReified()) {
            tmp = other.getReified();
            tmp.setReifier(this);
        }

        // Change all constructs that use other as type
        tiidx = this.parnt.typeInstanceIndex;
        MergeHelper.moveTypes(tiidx.getOccurrences(other), this);
        MergeHelper.moveTypes(tiidx.getNames(other), this);
        MergeHelper.moveTypes(tiidx.getAssociations(other), this);
        MergeHelper.moveTypes(tiidx.getRoles(other), this);

        // Change all topics that have other as type
        arr = tiidx.getTopics(other);
        for (i = 0; i < arr.length; i += 1) {
            arr[i].removeType(other);
            arr[i].addType(this);
        }

        // Change all constructs that use other as theme
        sidx = this.parnt.scopedIndex;
        MergeHelper.moveThemes(sidx.getAssociations(other), other, this);
        MergeHelper.moveThemes(sidx.getOccurrences(other), other, this);
        MergeHelper.moveThemes(sidx.getNames(other), other, this);
        MergeHelper.moveThemes(sidx.getVariants(other), other, this);

        MergeHelper.moveItemIdentifiers(other, this);

        arr = other.getSubjectLocators();
        while (arr.length) {
            tmp = arr[arr.length - 1];
            other.removeSubjectLocator(tmp);
            this.addSubjectLocator(tmp);
        }

        arr = other.getSubjectIdentifiers();
        while (arr.length) {
            tmp = arr[arr.length - 1];
            other.removeSubjectIdentifier(tmp);
            this.addSubjectIdentifier(tmp);
        }

        arr = other.getTypes();
        while (arr.length) {
            tmp = arr[arr.length - 1];
            other.removeType(tmp);
            this.addType(tmp);
        }

        // merge roles played
        arr = this.getRolesPlayed();
        signatures = {};
        for (i = 0; i < arr.length; i += 1) {
            tmp2 = arr[i].getParent();
            signatures[SignatureGenerator.makeAssociationSignature(tmp2)] = tmp2;
        }
        arr = other.getRolesPlayed();
        for (i = 0; i < arr.length; i += 1) {
            tmp = arr[i];
            tmp.setPlayer(this);
            if ((tmp2 = signatures[SignatureGenerator.makeAssociationSignature(tmp.getParent())])) {
                MergeHelper.moveItemIdentifiers(tmp.getParent(), tmp2);
                MergeHelper.moveReifier(tmp.getParent(), tmp2);
                tmp.getParent().remove();
            }
        }

        // merge names
        arr = this.getNames();
        signatures = {};
        for (i = 0; i < arr.length; i += 1) {
            signatures[SignatureGenerator.makeNameSignature(arr[i])] = arr[i];
        }
        arr = other.getNames();
        for (i = 0; i < arr.length; i += 1) {
            tmp = arr[i];
            if ((tmp2 = signatures[SignatureGenerator.makeNameSignature(arr[i])])) {
                MergeHelper.moveItemIdentifiers(tmp, tmp2);
                MergeHelper.moveReifier(tmp, tmp2);
                MergeHelper.moveVariants(tmp, tmp2);
                tmp.remove();
            } else {
                tmp2 = this.createName(tmp.getValue(), tmp.getType(), tmp.getScope());
                MergeHelper.moveVariants(tmp, tmp2);
            }
        }

        // merge occurrences
        arr = this.getOccurrences();
        signatures = {};
        for (i = 0; i < arr.length; i += 1) {
            signatures[SignatureGenerator.makeOccurrenceSignature(arr[i])] = arr[i];
        }
        arr = other.getOccurrences();
        for (i = 0; i < arr.length; i += 1) {
            tmp = arr[i];
            if ((tmp2 = signatures[SignatureGenerator.makeOccurrenceSignature(arr[i])])) {
                MergeHelper.moveItemIdentifiers(tmp, tmp2);
                MergeHelper.moveReifier(tmp, tmp2);
                tmp.remove();
            } else {
                tmp2 = this.createOccurrence(tmp.getType(), tmp.getValue(),
                    tmp.getDatatype(), tmp.getScope());
                MergeHelper.moveReifier(tmp, tmp2);
            }
        }

        other.remove();
        return this;
    };
    
    /**
     * Removes this topic from the containing TopicMap instance.
     * @throws {TopicInUseException} If the topics is used as reifier,
     * occurrence type, name type, association type, role type, topic type,
     * association theme, occurrence theme, name theme, variant theme,
     * or if it is used as a role player.
     */
    Topic.prototype.remove = function () {
        var tiidx = this.parnt.typeInstanceIndex,
            sidx = this.parnt.scopedIndex;
        if (this.getReified() ||
            tiidx.getOccurrences(this).length ||
            tiidx.getNames(this).length ||
            tiidx.getAssociations(this).length ||
            tiidx.getRoles(this).length ||
            tiidx.getTopics(this).length ||
            sidx.getAssociations(this).length ||
            sidx.getOccurrences(this).length ||
            sidx.getNames(this).length ||
            sidx.getVariants(this).length ||
            this.getRolesPlayed().length) {
            throw {name: 'TopicInUseException',
                message: '', reporter: this};
        }
        this.parnt._removeTopic(this);
        this.parnt._id2construct.remove(this.id);
        this.parnt.removeTopicEvent.fire(this);
        this.id = null;
        return this.parnt;
    };
    
    /**
     * Removes a subject identifier from this topic.
     * @returns {Topic} The topic itself (for chaining support)
     */
    Topic.prototype.removeSubjectIdentifier = function (subjectIdentifier) {
        for (var i = 0; i < this.subjectIdentifiers.length; i += 1) {
            if (this.subjectIdentifiers[i].getReference() ===
                subjectIdentifier.getReference()) {
                this.subjectIdentifiers.splice(i, 1);
                break;
            }
        }
        this.parnt._sl2topic.remove(subjectIdentifier.getReference());
        return this;
    };
    
    /**
     * Removes a subject locator from this topic.
     * @returns {Topic} The topic itself (for chaining support)
     */
    Topic.prototype.removeSubjectLocator = function (subjectLocator) {
        for (var i = 0; i < this.subjectLocators.length; i += 1) {
            if (this.subjectLocators[i].getReference() ===
                subjectLocator.getReference()) {
                this.subjectLocators.splice(i, 1);
                break;
            }
        }
        this.parnt._sl2topic.remove(subjectLocator.getReference());
        return this;
    };
    
    /**
     * Removes a type from this topic.
     * @returns {Topic} The topic itself (for chaining support)
     */
    Topic.prototype.removeType = function (type) {
        for (var i = 0; i < this.types.length; i += 1) {
            if (this.types[i].equals(type)) {
                this.types.splice(i, 1);
                this.parnt.removeTypeEvent.fire(this, {type: type});
                break;
            }
        }
    };
    
    Topic.prototype._removeName = function (name) {
        for (var i = 0; i < this.names.length; i += 1) {
            if (this.names[i].equals(name)) {
                this.names.splice(i, 1);
                break;
            }
        }
        this.getTopicMap()._removeName(name);
    };
    
    // --------------------------------------------------------------------------
    Occurrence = function (parnt, type, value, datatype) {
        this.itemIdentifiers = [];
        this.parnt = parnt;
        this.type = type;
        this.value = value;
        this.datatype = datatype ? datatype : this.getTopicMap().createLocator(XSD.string);
        this.scope = [];
        this.reifier = null;
        this.id = this.getTopicMap()._getConstructId();
        this.getTopicMap()._id2construct.put(this.id, this);
    };
    
    // mergein Typed, DatatypeAware, Reifiable, Scoped, Construct
    Occurrence.swiss(Typed, 'getType', 'setType');
    Occurrence.swiss(DatatypeAware, 'decimalValue', 'floatValue',
        'getDatatype', 'getValue', 'integerValue', 'locatorValue', 'longValue',
        'setValue');
    Occurrence.swiss(Reifiable, 'getReifier', 'setReifier');
    Occurrence.swiss(Scoped, 'addTheme', 'getScope', 'removeTheme');
    Occurrence.swiss(Construct, 'addItemIdentifier', 'equals', 'getId',
        'getItemIdentifiers', 'getParent', 'getTopicMap', 'hashCode', 'remove',
        'removeItemIdentifier', 'isTopic', 'isAssociation', 'isRole',
        'isOccurrence', 'isName', 'isVariant', 'isTopicMap');
    
    Occurrence.prototype.isOccurrence = function () {
        return true;
    };
    
    Occurrence.prototype.getTopicMap = function () {
        return this.parnt.getParent();
    };
    
    Occurrence.prototype.remove = function () {
        var i;
        for (i = 0; i < this.scope.length; i += 1) {
            this.parnt.parnt.removeThemeEvent.fire(this, {theme: this.scope[i]});
        }
        this.parnt.parnt.removeOccurrenceEvent.fire(this);
        this.parnt._removeOccurrence(this);
        this.id = null;
        return this.parnt;
    };
    
    Name = function (parnt, value, type) {
        this.itemIdentifiers = [];
        this.parnt = parnt;
        this.value = value;
        this.scope = [];
        this.id = this.getTopicMap()._getConstructId();
        this.type = type ||
            parnt.parnt.createTopicBySubjectIdentifier(
                parnt.parnt.createLocator('http://psi.topicmaps.org/iso13250/model/topic-name'));
        this.reifier = null;
        this.variants = [];
        this.getTopicMap()._id2construct.put(this.id, this);
        this.parnt.parnt.addNameEvent.fire(this, {type: this.type, value: value});
    };
    
    // mergein Typed, DatatypeAware, Reifiable, Scoped, Construct
    Name.swiss(Typed, 'getType', 'setType');
    Name.swiss(Reifiable, 'getReifier', 'setReifier');
    Name.swiss(Scoped, 'addTheme', 'getScope', 'removeTheme');
    Name.swiss(Construct, 'addItemIdentifier', 'equals', 'getId',
        'getItemIdentifiers', 'getParent', 'getTopicMap', 'hashCode', 'remove',
        'removeItemIdentifier', 'isTopic', 'isAssociation', 'isRole',
        'isOccurrence', 'isName', 'isVariant', 'isTopicMap');
    
    Name.prototype.isName = function () {
        return true;
    };
    
    Name.prototype.getTopicMap = function () {
        return this.parnt.parnt;
    };
    
    /**
     * @throws {ModelConstraintException} If scope is null.
     */
    Name.prototype.createVariant = function (value, datatype, scope) {
        var scope_length = 0, i, variant;
        if (typeof scope === 'undefined' || scope === null) {
            throw {name: 'ModelConstraintException',
            message: 'Creation of a variant with a null scope is not allowed'};
        }
        if (scope && typeof scope === 'object') {
            if (scope instanceof Array) {
                scope_length = scope.length;
            } else if (scope instanceof Topic) {
                scope_length = 1;
            }
        }
       /* 
        TODO: Compare scope of Name and Variant
        if (scope_length <= this.getScope().length) {
            // check if the variants scope contains more scoping topics
            throw {name: 'ModelConstraintException',
            message: 'The variant would be in the same scope as the parent'};
        }*/
        variant = new Variant(this, value, datatype);
        addScope(variant, scope);
        for (i = 0; i < this.scope.length; i += 1) {
            this.getTopicMap().addThemeEvent.fire(variant,
                {theme: this.scope[i]});
        }
        this.variants.push(variant);
        return variant;
    };
    
    /**
     * @throws {ModelConstraintException} If value is null.
     * @returns {Name} The name itself (for chaining support)
     */
    Name.prototype.setValue = function (value) {
        if (!value) {
            throw {name: 'ModelConstraintException',
            message: 'Name.setValue(null) is not allowed'};
        }
        this.value = value;
        return this;
    };
    
    Name.prototype.getValue = function (value) {
        return this.value;
    };
    
    Name.prototype.remove = function () {
        var i;
        for (i = 0; i < this.scope.length; i += 1) {
            this.parnt.parnt.removeThemeEvent.fire(this, {theme: this.scope[i]});
        }
        this.parnt.parnt.removeNameEvent.fire(this);
        this.parnt._removeName(this);
        this.id = null;
        return this.parnt;
    };
    
    Name.prototype._removeVariant = function (variant) {
        for (var i = 0; i < this.variants.length; i += 1) {
            if (this.variants[i].equals(variant)) {
                this.variants.splice(i, 1);
                break;
            }
        }
        this.getTopicMap()._removeVariant(variant);
    };

    Name.prototype.getVariants = function () {
        return this.variants;
    };
    
    /**
     * @throws {ModelConstraintException} If value or datatype is null.
     */
    Variant = function (parnt, value, datatype) {
        if (value === null) {
            throw {name: 'ModelConstraintException',
                message: 'Creation of a variant with null value is not allowed'};
        }
        if (datatype === null) {
            throw {name: 'ModelConstraintException',
            message: 'Creation of a variant with datatype == null is not allowed'};
        }
        this.itemIdentifiers = [];
        this.scope = [];
        this.parnt = parnt;
        if (typeof value === 'object' && value instanceof Locator) {
            this.datatype = this.getTopicMap().createLocator('http://www.w3.org/2001/XMLSchema#anyURI');
        } else {
            this.datatype = 
                this.getTopicMap().createLocator(XSD.string);
        }
        this.datatype = datatype;
        this.reifier = null;
        this.value = value;
        this.id = this.getTopicMap()._getConstructId();
        this.getTopicMap()._id2construct.put(this.id, this);
    };
    
    Variant.swiss(Reifiable, 'getReifier', 'setReifier');
    Variant.swiss(Scoped, 'addTheme', 'getScope', 'removeTheme');
    Variant.swiss(Construct, 'addItemIdentifier', 'equals', 'getId',
        'getItemIdentifiers', 'getParent', 'getTopicMap', 'hashCode', 'remove',
        'removeItemIdentifier', 'isTopic', 'isAssociation', 'isRole',
        'isOccurrence', 'isName', 'isVariant', 'isTopicMap');
    Variant.swiss(DatatypeAware, 'decimalValue', 'floatValue', 'getDatatype',
        'getValue', 'integerValue', 'locatorValue', 'longValue', 'setValue');
    
    Variant.prototype.isVariant = function () {
        return true;
    };
    
    Variant.prototype.getTopicMap = function () {
        return this.getParent().getParent().getParent();
    };
    
    Variant.prototype.remove = function () {
        var i;
        for (i = 0; i < this.scope.length; i += 1) {
            this.getTopicMap().removeThemeEvent.fire(this, {theme: this.scope[i]});
        }
        this.getParent()._removeVariant(this);
        this.id = null;
        return this.parnt;
    };
    

    Role = function (parnt, type, player) {
        this.itemIdentifiers = [];
        this.parnt = parnt;
        this.type = type;
        this.player = player;
        this.id = this.getTopicMap()._getConstructId();
        this.reifier = null;
        this.getTopicMap()._id2construct.put(this.id, this);
    };
    
    Role.swiss(Typed, 'getType', 'setType');
    Role.swiss(Reifiable, 'getReifier', 'setReifier');
    Role.swiss(Construct, 'addItemIdentifier', 'equals', 'getId',
        'getItemIdentifiers', 'getParent', 'getTopicMap', 'hashCode', 'remove',
        'removeItemIdentifier', 'isTopic', 'isAssociation', 'isRole',
        'isOccurrence', 'isName', 'isVariant', 'isTopicMap');
    
    Role.prototype.isRole = function () {
        return true;
    };
    
    Role.prototype.getTopicMap = function () {
        return this.getParent().getParent();
    };
    
    Role.prototype.remove = function () {
        var parnt = this.parnt;
        this.parnt.parnt.removeRoleEvent.fire(this);
        this.parnt._removeRole(this);
        this.itemIdentifiers = null;
        this.parnt = null;
        this.type = null;
        this.player = null;
        this.reifier = null;
        this.id = null;
        return parnt;
    };
    
    Role.prototype.getPlayer = function () {
        return this.player;
    };
    
    /**
     * @throws {ModelConstraintException} If player is null.
     * @returns {Role} The role itself (for chaining support)
     */
    Role.prototype.setPlayer = function (player) {
        if (!player) {
            throw {name: 'ModelConstraintException',
            message: 'player i Role.setPlayer cannot be null'};
        }
        SameTopicMapHelper.assertBelongsTo(this.parnt.parnt, player);
        if (this.player.equals(player)) {
            return;
        }
        this.player.removeRolePlayed(this);
        player.addRolePlayed(this);
        this.player = player;
        return this;
    };
    
    Association = function (par) {
        this.itemIdentifiers = [];
        this.parnt = par;
        this.id = this.getTopicMap()._getConstructId();
        this.getTopicMap()._id2construct.put(this.id, this);
        this.roles = [];
        this.scope = [];
        this.type = null;
        this.reifier = null;
    };
    
    Association.swiss(Typed, 'getType', 'setType');
    Association.swiss(Reifiable, 'getReifier', 'setReifier');
    Association.swiss(Scoped, 'addTheme', 'getScope', 'removeTheme');
    Association.swiss(Construct, 'addItemIdentifier', 'equals', 'getId',
        'getItemIdentifiers', 'getParent', 'getTopicMap', 'hashCode', 'remove',
        'removeItemIdentifier', 'isTopic', 'isAssociation', 'isRole',
        'isOccurrence', 'isName', 'isVariant', 'isTopicMap');
    
    Association.prototype.isAssociation = function () {
        return true;
    };
    
    Association.prototype.getTopicMap = function () {
        return this.parnt;
    };
    
    /**
     * Creates a new Role representing a role in this association.
     * @throws {ModelConstraintException} If type or player is null.
     */
    Association.prototype.createRole = function (type, player) {
        if (!type) {
            throw {name: 'ModelConstraintException',
                message: 'type i Role.createPlayer cannot be null'};
        }
        if (!player) {
            throw {name: 'ModelConstraintException',
                message: 'player i Role.createRole cannot be null'};
        }
        SameTopicMapHelper.assertBelongsTo(this.parnt, type);
        SameTopicMapHelper.assertBelongsTo(this.parnt, player);
        var role = new Role(this, type, player);
        player.addRolePlayed(role);
        this.roles.push(role);
        this.parnt.addRoleEvent.fire(role, {type: type, player: player});
        return role;
    };
    
    Association.prototype._removeRole = function (role) {
        for (var i = 0; i < this.roles.length; i += 1) {
            if (role.id === this.roles[i].id) {
                this.roles.splice(i, 1);
                break;
            }
        }
        role.getPlayer().removeRolePlayed(role);
        this.getTopicMap()._removeRole(role);
    };
    
    Association.prototype.remove = function () {
        var i;
        for (i = 0; i < this.scope.length; i += 1) {
            this.parnt.removeThemeEvent.fire(this, {theme: this.scope[i]});
        }
        this.parnt.removeAssociationEvent.fire(this);
        while (this.roles.length) {
            this.roles[0].remove();
        }
        this.id = null;
        this.roles = null;
        this.parnt._removeAssociation(this);
        this.getTopicMap()._ii2construct.remove(this.id);
        this.item_identifiers = null;
        this.scope = null;
        this.type = null;
        this.reifier = null;
        return this.parnt;
    };
    
    /**
     * Returns the roles participating in this association, or, if type
     * is given, all roles with the specified type.
     * @throws {IllegalArgumentException} If type is null.
     */
    Association.prototype.getRoles = function (type) {
        if (type === null) {
            throw {name: 'IllegalArgumentException',
                message: 'Topic.getRoles cannot be called with type null'};
        }
        if (!type) {
            return this.roles;
        }
        var ret = [], i; 
        for (i = 0; i < this.roles.length; i += 1) {
            if (this.roles[i].getType().equals(type)) {
                ret.push(this.roles[i]);
            }
        }
        return ret;
    };

    /**
     * Returns the role types participating in this association.
     */
    Association.prototype.getRoleTypes = function () {
        // Create a hash with the object ids as keys to avoid duplicates
        var types = {}, typearr = [], i, t;
        for (i = 0; i < this.roles.length; i += 1) {
            types[this.roles[i].getType().getId()] =
                this.roles[i].getType();
        }
        for (t in types) {
            if (types.hasOwnProperty(t)) {
                typearr.push(types[t]);
            }
        }
        return typearr;
    };

    // ------ ----------------------------------------------------------------
    /** @class */
    Index = function () {
        this.opened = false;
    };

    /**
     * Close the index.
     */
    Index.prototype.close = function () {
        return;
    };

    /** 
     * Indicates whether the index is updated automatically. 
     * @returns {boolean}
     */
    Index.prototype.isAutoUpdated = function () {
        return true;
    };

    /** Indicates if the index is open.
     * @returns {boolean} true if index is already opened, false otherwise.
     */
    Index.prototype.isOpen = function () {
        return this.opened;
    };

    /**
     * Opens the index. This method must be invoked before using any other
     * method (aside from isOpen()) exported by this interface or derived
     * interfaces.
     */
    Index.prototype.open = function () {
        this.opened = true;
    };

    /**
     * Synchronizes the index with data in the topic map.
     */
    Index.prototype.reindex = function () {
        return;
    };

    /**
     * Creates a new instance of TypeInstanceIndex.
     * @class Implementation of the TypeInstanceIndex interface.
     */
    TypeInstanceIndex = function (tm) {
        var eventHandler, that = this;
        this.tm = tm;
        // we use hash tables of hash tables for our index
        this.type2topics = new Hash();
        this.type2associations = new Hash();
        this.type2roles = new Hash();
        this.type2occurrences = new Hash();
        this.type2names = new Hash();
        this.type2variants = new Hash();
        this.opened = false;

        eventHandler = function (eventtype, source, obj) {
            var existing, untyped, types, type, i;
            switch (eventtype) {
            case EventType.ADD_ASSOCIATION:
                break;
            case EventType.ADD_NAME:
                existing = that.type2names.get(obj.type.getId());
                if (typeof existing === 'undefined') {
                    existing = new Hash();
                }
                existing.put(source.getId(), source);
                that.type2names.put(obj.type.getId(), existing);
                break;
            case EventType.ADD_OCCURRENCE:
                existing = that.type2occurrences.get(obj.type.getId());
                if (typeof existing === 'undefined') {
                    existing = new Hash();
                }
                existing.put(source.getId(), source);
                that.type2occurrences.put(obj.type.getId(), existing);
                break;
            case EventType.ADD_ROLE:
                existing = that.type2roles.get(obj.type.getId());
                if (typeof existing === 'undefined') {
                    existing = new Hash();
                }
                existing.put(source.getId(), source);
                that.type2roles.put(obj.type.getId(), existing);
                break;
            case EventType.ADD_TOPIC:
                existing = that.type2topics.get('null');
                if (typeof existing === 'undefined') {
                    existing = new Hash();
                }
                existing.put(source.getId(), source);
                that.type2topics.put('null', existing);
                break;
            case EventType.ADD_TYPE:
                // check if source exists with type null, remove it there
                untyped = that.type2topics.get('null');
                if (untyped && untyped.get(source.getId())) {
                    untyped.remove(source.getId());
                    that.type2topics.put('null', untyped);
                }
                    
                existing = that.type2topics.get(obj.type.getId());
                if (typeof existing === 'undefined') {
                    existing = new Hash();
                }
                existing.put(source.getId(), source);
                that.type2topics.put(obj.type.getId(), existing);
                break;
            case EventType.REMOVE_ASSOCIATION:
                type = source.getType();
                if (!type) {
                    break;
                }
                existing = that.type2associations.get(type.getId());
                for (i = 0; i < existing.length; i += 1) {
                    if (existing[i].equals(source)) {
                        existing.splice(i, 1);
                        break;
                    }    
                }
                if (existing.length > 0) {
                    that.type2associations.put(type.getId(),
                            existing);
                } else {
                    that.type2associations.remove(type.getId());
                }
                break;
            case EventType.REMOVE_NAME:
                type = source.getType();
                existing = that.type2names.get(type.getId());
                existing.remove(source.getId());
                if (existing.length > 0) {
                    that.type2names.put(type.getId(), existing);
                } else {
                    that.type2names.remove(type.getId());
                }
                break;
            case EventType.REMOVE_OCCURRENCE:
                type = source.getType();
                existing = that.type2occurrences.get(type.getId());
                existing.remove(source.getId());
                if (existing.length > 0) {
                    that.type2occurrences.put(type.getId(), existing);
                } else {
                    that.type2occurrences.remove(type.getId());
                }
                break;
            case EventType.REMOVE_ROLE:
                type = source.getType();
                existing = that.type2roles.get(type.getId());
                existing.remove(source.getId());
                if (existing.length > 0) {
                    that.type2roles.put(type.getId(), existing);
                } else {
                    that.type2roles.remove(type.getId());
                }
                break;
            case EventType.REMOVE_TOPIC:
                // two cases:
                //  topic has types
                types = source.getTypes();
                for (i = 0; i < types.length; i += 1) {
                    existing = that.type2topics.get(types[i].getId());
                    existing.remove(source.getId());
                    if (!existing.size()) {
                        that.type2topics.remove(types[i].getId());
                    }
                }
                // topic used as type 
                that.type2topics.remove(source.getId());
                that.type2associations.remove(source.getId());
                that.type2roles.remove(source.getId());
                that.type2occurrences.remove(source.getId());
                that.type2variants.remove(source.getId());
                break;
            case EventType.REMOVE_TYPE:
                existing = that.type2topics.get(obj.type.getId());
                existing.remove(source.getId());
                if (!existing.size()) {
                    that.type2topics.remove(obj.type.getId());
                }
                if (source.getTypes().length === 0) {
                    untyped = that.type2topics.get('null');
                    if (typeof untyped === 'undefined') {
                        untyped = new Hash();
                    }
                    untyped.put(source.getId(), source);
                }
                break;
            case EventType.SET_TYPE:
                if (source.isAssociation()) {
                    // remove source from type2associations(obj.old.getId());
                    if (obj.old) {
                        existing = that.type2associations.get(obj.old.getId());
                        for (i = 0; i < existing.length; i += 1) {
                            if (existing[i].equals(source)) {
                                existing.splice(i, 1);
                                break;
                            }    
                        }
                        if (existing.length > 0) {
                            that.type2associations.put(obj.old.getId(),
                                    existing);
                        } else {
                            that.type2associations.remove(obj.old.getId());
                        }
                    }
                    existing = that.type2associations.get(obj.type.getId());
                    if (typeof existing === 'undefined') {
                        existing = [];
                    }
                    existing.push(source);
                    that.type2associations.put(obj.type.getId(), existing);
                } else if (source.isName()) {
                    existing = that.type2names.get(obj.old.getId());
                    if (existing) {
                        existing.remove(source.getId());
                        if (existing.length > 0) {
                            that.type2names.put(obj.old.getId(), existing);
                        } else {
                            that.type2names.remove(obj.old.getId());
                        }
                    }
                    existing = that.type2names.get(obj.type.getId());
                    if (typeof existing === 'undefined') {
                        existing = new Hash();
                    }
                    existing.put(source.getId(), source);
                    that.type2names.put(obj.type.getId(), existing);
                } else if (source.isOccurrence()) {
                    existing = that.type2occurrences.get(obj.old.getId());
                    if (existing) {
                        existing.remove(source.getId());
                        if (existing.length > 0) {
                            that.type2occurrences.put(obj.old.getId(), existing);
                        } else {
                            that.type2occurrences.remove(obj.old.getId());
                        }
                    }
                    existing = that.type2occurrences.get(obj.type.getId());
                    if (typeof existing === 'undefined') {
                        existing = new Hash();
                    }
                    existing.put(source.getId(), source);
                    that.type2occurrences.put(obj.type.getId(), existing);
                } else if (source.isRole()) {
                    existing = that.type2roles.get(obj.old.getId());
                    if (existing) {
                        existing.remove(source.getId());
                        if (existing.length > 0) {
                            that.type2roles.put(obj.old.getId(), existing);
                        } else {
                            that.type2roles.remove(obj.old.getId());
                        }
                    }
                    existing = that.type2roles.get(obj.type.getId());
                    if (typeof existing === 'undefined') {
                        existing = new Hash();
                    }
                    existing.put(source.getId(), source);
                    that.type2roles.put(obj.type.getId(), existing);
                }
                break;
            }
        };
        tm.addAssociationEvent.registerHandler(eventHandler);
        tm.addNameEvent.registerHandler(eventHandler);
        tm.addOccurrenceEvent.registerHandler(eventHandler);
        tm.addRoleEvent.registerHandler(eventHandler);
        tm.addTopicEvent.registerHandler(eventHandler);
        tm.addTypeEvent.registerHandler(eventHandler);
        tm.removeAssociationEvent.registerHandler(eventHandler);
        tm.removeNameEvent.registerHandler(eventHandler);
        tm.removeOccurrenceEvent.registerHandler(eventHandler);
        tm.removeRoleEvent.registerHandler(eventHandler);
        tm.removeTopicEvent.registerHandler(eventHandler);
        tm.removeTypeEvent.registerHandler(eventHandler);
        tm.setTypeEvent.registerHandler(eventHandler);
    };

    TypeInstanceIndex.swiss(Index, 'close', 'isAutoUpdated',
        'isOpen', 'open', 'reindex');
          
    /**
     * Returns the associations in the topic map whose type property equals type.
     *
     * @param {Topic} type
     * @returns {Array} A list of all associations in the topic map with the given type.
     */
    TypeInstanceIndex.prototype.getAssociations = function (type) {
        var ret = this.type2associations.get(type.getId());
        if (!ret) {
            return [];
        }
        return ret;
    };

    /**
     * Returns the topics in the topic map used in the type property of Associations.
     *
     * @returns {Array} A list of all topics that are used as an association type.
     */
    TypeInstanceIndex.prototype.getAssociationTypes = function () {
        var ret = [], keys = this.type2associations.keys(), i;
        for (i = 0; i < keys.length; i += 1) {
            ret.push(this.tm.getConstructById(keys[i]));
        }
        return ret;
    };

    /**
     * Returns the topic names in the topic map whose type property equals type.
     *
     * @param {Topic} type
     * @returns {Array}
     */
    TypeInstanceIndex.prototype.getNames = function (type) {
        var ret = this.type2names.get(type.getId());
        if (!ret) {
            return [];
        }
        return ret.values();
    };

    /**
     * Returns the topics in the topic map used in the type property of Names.
     *
     * @returns {Array} An array of topic types. Note that the array contains
     * a reference to the actual topics, not copies of them.
     */
    TypeInstanceIndex.prototype.getNameTypes = function () {
        var ret = [], keys = this.type2names.keys(), i;
        for (i = 0; i < keys.length; i += 1) {
            ret.push(this.tm.getConstructById(keys[i]));
        }
        return ret;
    };

    /**
     * Returns the occurrences in the topic map whose type property equals type.
     *
     * @returns {Array}
     */
    TypeInstanceIndex.prototype.getOccurrences = function (type) {
        var ret = this.type2occurrences.get(type.getId());
        if (!ret) {
            return [];
        }
        return ret.values();
    };

    /**
     * Returns the topics in the topic map used in the type property of
     * Occurrences.
     *
     * @returns {Array} An array of topic types. Note that the array contains
     * a reference to the actual topics, not copies of them.
     */
    TypeInstanceIndex.prototype.getOccurrenceTypes = function () {
        var ret = [], keys = this.type2occurrences.keys(), i;
        for (i = 0; i < keys.length; i += 1) {
            ret.push(this.tm.getConstructById(keys[i]));
        }
        return ret;
    };


    /**
     * Returns the roles in the topic map whose type property equals type.
     *
     * @returns {Array}
     */
    TypeInstanceIndex.prototype.getRoles = function (type) {
        var ret = this.type2roles.get(type.getId());
        if (!ret) {
            return [];
        }
        return ret.values();
    };

    /**
     * Returns the topics in the topic map used in the type property of Roles.
     *
     * @returns {Array} An array of topic types. Note that the array contains
     * a reference to the actual topics, not copies of them.
     */
    TypeInstanceIndex.prototype.getRoleTypes = function () {
        var ret = [], keys = this.type2roles.keys(), i;
        for (i = 0; i < keys.length; i += 1) {
            ret.push(this.tm.getConstructById(keys[i]));
        }
        return ret;
    };

    /**
     * Returns the topics which are an instance of the specified type.
     */
    TypeInstanceIndex.prototype.getTopics = function (type) {
        var ret = this.type2topics.get((type ? type.getId() : 'null'));
        if (!ret) {
            return [];
        }
        return ret.values();
    };

    /**
     * Returns the topics which are an instance of the specified types.
     * If matchall is true only topics that have all of the listed types
     * are returned.
     * @returns {Array} A list of Topic objects
     */
    TypeInstanceIndex.prototype.getTopicsByTypes = function (types, matchall) {
        var instances, i, j;
        instances = IndexHelper.getForKeys(this.type2topics, types);
        if (!matchall) {
            return instances;
        }
        // If matchall is true, we check all values for all types in {types}
        // It's a hack, but will do for now
        for (i = 0; i < instances.length; i += 1) {
            for (j = 0; j < types.length; j += 1) {
                if (!ArrayHelper.contains(instances[i].getTypes(), types[j])) {
                    instances.splice(i, 1);
                    i -= 1;
                    break;
                }
            }
        }
        return instances;
    };

    /**
     * Returns the topics in topic map which are used as type in an
     * "type-instance"-relationship.
     */
    TypeInstanceIndex.prototype.getTopicTypes = function () {
        var ret = [], keys = this.type2topics.keys(), i;
        for (i = 0; i < keys.length; i += 1) {
            if (keys[i] !== 'null') {
                ret.push(this.tm.getConstructById(keys[i]));
            }
        }
        return ret;
    };

    TypeInstanceIndex.prototype.close = function () {
        return;
    };


    /**
     * Index for Scoped statements and their scope. This index provides access
     * to Associations, Occurrences, Names, and Variants by their scope
     * property and to Topics which are used as theme in a scope. 
     */
    ScopedIndex = function (tm) {
        var that = this, eventHandler;
        this.tm = tm;
        this.theme2associations = new Hash();
        this.theme2names = new Hash();
        this.theme2occurrences = new Hash();
        this.theme2variants = new Hash();
        eventHandler = function (eventtype, source, obj) {
            var existing, key, unscoped, remove_from_index, add_to_index;
            add_to_index = function (hash, source, obj) {
                key = (obj.theme ? obj.theme.getId() : 'null');

                // check if source exists with theme null, remove it there
                // this is the case iff source now has one scoping topic
                if (source.getScope().length === 1) {
                    unscoped = hash.get('null');
                    if (unscoped && unscoped.get(source.getId())) {
                        unscoped.remove(source.getId());
                        hash.put('null', unscoped);
                    }
                }
                existing = hash.get(key);
                if (typeof existing === 'undefined') {
                    existing = new Hash();
                }
                existing.put(source.getId(), source);  
                hash.put(key, existing);
            };
            remove_from_index = function (hash, source, obj) {
                key = obj.theme.getId();
                existing = hash.get(key);
                if (typeof existing !== 'undefined') {
                    existing.remove(source.getId());  
                    if (!existing.size()) {
                        hash.remove(key);
                    }
                }
            };
            switch (eventtype) {
            case EventType.ADD_THEME:
                if (source.isAssociation()) {
                    add_to_index(that.theme2associations, source, obj);
                } else if (source.isName()) {
                    add_to_index(that.theme2names, source, obj);
                } else if (source.isOccurrence()) {
                    add_to_index(that.theme2occurrences, source, obj);
                } else if (source.isVariant()) {
                    add_to_index(that.theme2variants, source, obj);
                }
                break;
            case EventType.REMOVE_THEME:
                if (source.isAssociation()) {
                    remove_from_index(that.theme2associations, source, obj);
                } else if (source.isName()) {
                    remove_from_index(that.theme2names, source, obj);
                } else if (source.isOccurrence()) {
                    remove_from_index(that.theme2occurrences, source, obj);
                } else if (source.isVariant()) {
                    remove_from_index(that.theme2variants, source, obj);
                }
                break;
            }
        };
        tm.addThemeEvent.registerHandler(eventHandler);
        tm.removeThemeEvent.registerHandler(eventHandler);
    };

    ScopedIndex.swiss(Index, 'close', 'isAutoUpdated',
        'isOpen', 'open', 'reindex');

    ScopedIndex.prototype.close = function () {
        return;
    };

    /**
     * Returns the Associations in the topic map whose scope property contains
     * the specified theme. The return value may be empty but must never be null. 
     * @param theme can be array or {Topic}
     * @param [matchall] boolean
     */
    ScopedIndex.prototype.getAssociations = function (theme) {
        var ret = this.theme2associations.get((theme ? theme.getId() : 'null'));
        if (!ret) {
            return [];
        }
        return ret.values();
    };

    /**
     * Returns the Associations in the topic map whose scope property contains
     * the specified theme. The return value may be empty but must never be null. 
     * @param theme can be array or {Topic}
     * @param [matchall] boolean
     * @throws {IllegalArgumentException} If themes is null.
     */
    ScopedIndex.prototype.getAssociationsByThemes = function (themes, matchall) {
        if (themes === null) {
            throw {name: 'IllegalArgumentException',
                message: 'ScopedIndex.getAssociationsByThemes cannot be called without themes'};
        }
        return IndexHelper.getConstructsByThemes(this.theme2associations,
            themes, matchall);
    };

    /**
     * Returns the topics in the topic map used in the scope property of
     * Associations.
     */
    ScopedIndex.prototype.getAssociationThemes = function () {
        return IndexHelper.getConstructThemes(this.tm, this.theme2associations);
    };

    /**
     * Returns the Names in the topic map whose scope property contains the
     * specified theme.
     */
    ScopedIndex.prototype.getNames = function (theme) {
        var ret = this.theme2names.get((theme ? theme.getId() : 'null'));
        if (!ret) {
            return [];
        }
        return ret.values();
    };

    /**
     * Returns the Names in the topic map whose scope property equals one of
     * those themes at least.
     * @throws {IllegalArgumentException} If themes is null.
     */
    ScopedIndex.prototype.getNamesByThemes = function (themes, matchall) {
        if (themes === null) {
            throw {name: 'IllegalArgumentException',
                message: 'ScopedIndex.getNamesByThemes cannot be called without themes'};
        }
        return IndexHelper.getConstructsByThemes(this.theme2names,
            themes, matchall);
    };

    /**
     * Returns the topics in the topic map used in the scope property of Names.
     */
    ScopedIndex.prototype.getNameThemes = function () {
        return IndexHelper.getConstructThemes(this.tm, this.theme2names);
    };

    /**
     * Returns the Occurrences in the topic map whose scope property contains the
     * specified theme.
     */
    ScopedIndex.prototype.getOccurrences = function (theme) {
        var ret = this.theme2occurrences.get((theme ? theme.getId() : 'null'));
        if (!ret) {
            return [];
        }
        return ret.values();
    };

    /**
     * Returns the Occurrences in the topic map whose scope property equals one
     * of those themes at least.
     * @throws {IllegalArgumentException} If themes is null.
     */
    ScopedIndex.prototype.getOccurrencesByThemes = function (themes, matchall) {
        if (themes === null) {
            throw {name: 'IllegalArgumentException',
                message: 'ScopedIndex.getOccurrencesByThemes cannot be called without themes'};
        }
        return IndexHelper.getConstructsByThemes(this.theme2occurrences,
            themes, matchall);
    };

    /**
     * Returns the topics in the topic map used in the scope property of
     * Occurrences.
     */
    ScopedIndex.prototype.getOccurrenceThemes = function () {
        return IndexHelper.getConstructThemes(this.tm, this.theme2occurrences);
    };

    /**
     * Returns the Variants in the topic map whose scope property contains the
     * specified theme. The return value may be empty but must never be null. 
     * @param {Topic} The Topic which must be part of the scope. This must not be
     * null. 
     * @returns {Array} An array of Variants.
     * @throws {IllegalArgumentException} If theme is null.
     */
    ScopedIndex.prototype.getVariants = function (theme) {
        if (theme === null) {
            throw {name: 'IllegalArgumentException',
                message: 'ScopedIndex.getVariants cannot be called without themes'};
        }
        var ret = this.theme2variants.get((theme ? theme.getId() : 'null'));
        if (!ret) {
            return [];
        }
        return ret.values();
    };

    /**
     * Returns the Variants in the topic map whose scope property equals one of
     * those themes at least.
     * @param {Array} themes Scope of the Variants to be returned.
     * @param {boolean} If true the scope property of a variant must match all
     * themes, if false one theme must be matched at least.
     * @returns {Array} An array of variants
     * @throws {IllegalArgumentException} If themes is null.
     */
    ScopedIndex.prototype.getVariantsByThemes = function (themes, matchall) {
        if (themes === null) {
            throw {name: 'IllegalArgumentException',
                message: 'ScopedIndex.getVariantsByThemes cannot be called without themes'};
        }
        return IndexHelper.getConstructsByThemes(this.theme2variants,
            themes, matchall);
    };

    /**
     * Returns the topics in the topic map used in the scope property of Variants.
     * The return value may be empty but must never be null.
     * @returns {Array} An array of Topics.
     */
    ScopedIndex.prototype.getVariantThemes = function () {
        return IndexHelper.getConstructThemes(this.tm, this.theme2variants);
    };




    /**
     * @class Helper class that is used to check if constructs belong to
     * a given topic map.
     */
    SameTopicMapHelper = {
        /**
         * Checks if topic belongs to the topicmap 'topicmap'.
         * topic can be instance of Topic or an Array with topics.
         * topic map be null.
         * @static
         * @throws ModelConstraintException if the topic(s) don't
         * belong to the same topic map.
         * @returns false if the topic was null or true otherwise.
         */
        assertBelongsTo: function (topicmap, topic) {
            var i;
            if (!topic) {
                return false;
            }
            if (topic && topic instanceof Topic &&
                    !topicmap.equals(topic.getTopicMap())) {
                throw {name: 'ModelConstraintException',
                    message: 'scope topic belongs to different topic map'};
            }
            if (topic && topic instanceof Array) {
                for (i = 0; i < topic.length; i += 1) {
                    if (!topicmap.equals(topic[i].getTopicMap())) {
                        throw {name: 'ModelConstraintException',
                            message: 'scope topic belong to different topic maps'};
                    }
                }
            }
            return true;
        }
    };

    /**
     * Helper functions for hashes of hashes
     * @ignore
     */
    IndexHelper = {
        getForKeys: function (hash, keys) {
            var i, j, tmp = new Hash(), value_hash, value_keys;
            for (i = 0; i < keys.length; i += 1) {
                value_hash = hash.get(keys[i].getId());
                if (value_hash) {
                    value_keys = value_hash.keys();
                    // we use a hash to store instances to avoid duplicates
                    for (j = 0; j < value_keys.length; j += 1) {
                        tmp.put(value_hash.get(value_keys[j]).getId(),
                                value_hash.get(value_keys[j]));
                    }
                }
            }
            return tmp.values();
        },

        getConstructThemes: function (tm, hash) {
            var ret = [], keys = hash.keys(), i;
            for (i = 0; i < keys.length; i += 1) {
                if (keys[i] !== 'null') {
                    ret.push(tm.getConstructById(keys[i]));
                }
            }
            return ret;
        },

        getConstructsByThemes: function (hash, themes, matchall) {
            var constructs, i, j;
            constructs = IndexHelper.getForKeys(hash, themes);
            if (!matchall) {
                return constructs;
            }
            // If matchall is true, we check all values for all types in {types}
            // It's a hack, but will do for now
            for (i = 0; i < constructs.length; i += 1) {
                for (j = 0; j < themes.length; j += 1) {
                    if (!ArrayHelper.contains(constructs[i].getScope(), themes[j])) {
                        constructs.splice(i, 1);
                        i -= 1;
                        break;
                    }
                }
            }
            return constructs;
        }
    };

    /** 
     * Helper functions for arrays. We don't modify the global array
     * object to avoid conflicts with other libraries.
     * @ignore
     */
    ArrayHelper = {
        /** Checks if arr contains elem */
        contains: function (arr, elem) {
            for (var key in arr) {
                if (arr.hasOwnProperty(key)) {
                    if (arr[key].equals(elem)) {
                        return true;
                    }
                }
            }
            return false;
        }
    };

    /** 
     * Internal function to add scope. scope may be Array, Topic or null.
     * @ignore
     * FIXME: Move to a class
     */
    addScope = function (construct, scope) {
        var i;
        if (scope && typeof scope === 'object') {
            if (scope instanceof Array) {
                for (i = 0; i < scope.length; i += 1) {
                    construct.addTheme(scope[i]);
                }
            } else if (scope instanceof Topic) {
                construct.addTheme(scope);
            }
        } else {
            construct.getTopicMap().addThemeEvent.fire(construct, {theme: null});
        }
    };

    /**
     * Helper class for generating signatures of Topic Maps constructs.
     */
    SignatureGenerator = {
        makeNameValueSignature: function (name) {
            return name.getValue();
        },

        makeNameSignature: function (name) {
            return SignatureGenerator.makeNameValueSignature(name) +
                '#' + SignatureGenerator.makeTypeSignature(name) +
                '#' + SignatureGenerator.makeScopeSignature(name);
        },

        makeOccurrenceSignature: function (occ) {
            return SignatureGenerator.makeOccurrenceValueSignature(occ) +
                '#' + SignatureGenerator.makeTypeSignature(occ) +
                '#' + SignatureGenerator.makeScopeSignature(occ);
        },

        makeOccurrenceValueSignature: function (occ) {
            return '#' + occ.getValue() + '#' +
                (occ.getDatatype() ? occ.getDatatype().getReference() : 'null');
        },

        makeTypeSignature: function (obj) {
            var type = obj.getType();
            if (type) {
                return type.getId();
            } else {
                return '';
            }
        },

        makeScopeSignature: function (scope) {
            var i, arr = [];
            for (i = 0; i < scope.length; i += 1) {
                arr.push(scope[i].getId());
            }
            arr.sort();
            return arr.join('#');
        },

        makeAssociationSignature: function (ass) {
            var roles, i, tmp = [];
            roles = ass.getRoles();
            for (i = 0; i < roles.length; i += 1) {
                tmp.push(SignatureGenerator.makeRoleSignature(roles[i]));
            }
            tmp.sort();
        
            return '#' + SignatureGenerator.makeTypeSignature(ass) + '#' + tmp.join('#') +
                SignatureGenerator.makeScopeSignature(ass);
        },

        makeRoleSignature: function (role) {
            return SignatureGenerator.makeTypeSignature(role) + '#' +
                role.getPlayer().getId();
        },

        makeVariantValueSignature: function (variant) {
            return '#' + variant.getValue() + '#' + variant.getDatatype().getReference();
        },

        makeVariantSignature: function (variant) {
            return SignatureGenerator.makeVariantValueSignature(variant) +
                '#' + SignatureGenerator.makeScopeSignature(variant);
        }
    };

    /**
     * Utility class that removes duplicates according to the TMDM.
     */
    DuplicateRemover = {
        removeTopicMapDuplicates: function (tm) {
            var i, topics, associations, sig2ass = new Hash(), sig, existing;
            topics = tm.getTopics();
            for (i = 0; i < topics.length; i += 1) {
                DuplicateRemover.removeOccurrencesDuplicates(topics[i].getOccurrences());
                DuplicateRemover.removeNamesDuplicates(topics[i].getNames());
            }
            associations = tm.getAssociations();
            for (i = 0; i < associations.length; i += 1) {
                DuplicateRemover.removeAssociationDuplicates(associations[i]);
                sig = SignatureGenerator.makeAssociationSignature(associations[i]);
                if ((existing = sig2ass.get(sig))) {
                    MergeHelper.moveConstructCharacteristics(associations[i], existing);
                    MergeHelper.moveRoleCharacteristics(associations[i], existing);
                    associations[i].remove();
                } else {
                    sig2ass.put(sig, associations[i]);
                }
            }
            sig2ass.empty();
        },

        removeOccurrencesDuplicates: function (occurrences) {
            var i, sig2occ = new Hash(), occ, sig, existing;
            for (i = 0; i < occurrences.length; i += 1) {
                occ = occurrences[i];
                sig = SignatureGenerator.makeOccurrenceSignature(occ);
                if ((existing = sig2occ.get(sig))) {
                    MergeHelper.moveConstructCharacteristics(occ, existing);
                    occ.remove();
                } else {
                    sig2occ.put(sig, occ);
                }
            }
            sig2occ.empty();
        },

        removeNamesDuplicates: function (names) {
            var i, sig2names = new Hash(), name, sig, existing;
            for (i = 0; i < names.length; i += 1) {
                name = names[i];
                DuplicateRemover.removeVariantsDuplicates(name.getVariants());
                sig = SignatureGenerator.makeNameSignature(name);
                if ((existing = sig2names.get(sig))) {
                    MergeHelper.moveConstructCharacteristics(name, existing);
                    MergeHelper.moveVariants(name, existing);
                    name.remove();
                } else {
                    sig2names.put(sig, name);
                }
            }
            sig2names.empty();
        },

        removeVariantsDuplicates: function (variants) {
            var i, sig2variants = new Hash(), variant, sig, existing;
            for (i = 0; i < variants.length; i += 1) {
                variant = variants[i];
                sig = SignatureGenerator.makeVariantSignature(variant);
                if ((existing = sig2variants.get(sig))) {
                    MergeHelper.moveConstructCharacteristics(variant, existing);
                    variant.remove();
                } else {
                    sig2variants.put(sig, variant);
                }
            }
            sig2variants.empty();
        },

        removeAssociationDuplicates: function (assoc) {
            var i, roles = assoc.getRoles(), sig2role = new Hash(), sig, existing;
            for (i = 0; i < roles.length; i += 1) {
                sig = SignatureGenerator.makeRoleSignature(roles[i]);
                if ((existing = sig2role.get(sig))) {
                    MergeHelper.moveConstructCharacteristics(roles[i], existing);
                    roles[i].remove();
                } else {
                    sig2role.put(sig, roles[i]);
                }
            }
        }
    };

    MergeHelper = {
        moveTypes: function (arr, target) {
            var i;
            for (i = 0; i < arr.length; i += 1) {
                arr[i].setType(target);
            }
        },

        moveThemes: function (arr, source, target) {
            for (var i = 0; i < arr.length; i += 1) {
                arr[i].removeTheme(source);
                arr[i].addTheme(target);
            }
        },

        moveItemIdentifiers: function (source, target) {
            var iis, ii;
            iis = source.getItemIdentifiers();
            while (iis.length) {
                ii = iis[iis.length - 1];
                source.removeItemIdentifier(ii);
                target.addItemIdentifier(ii);
            }
        },

        /**
         * Moves variants from the name source to the name target
         */
        moveVariants: function (source, target) {
            var arr, i, tmp, tmp2, signatures;
            arr = target.getVariants();
            signatures = {};
            for (i = 0; i < arr.length; i += 1) {
                signatures[SignatureGenerator.makeVariantSignature(arr[i])] = arr[i];
            }
            arr = source.getVariants();
            for (i = 0; i < arr.length; i += 1) {
                tmp = arr[i];
                if ((tmp2 = signatures[SignatureGenerator.makeVariantSignature(arr[i])])) {
                    MergeHelper.moveItemIdentifiers(tmp, tmp2);
                    MergeHelper.moveReifier(tmp, tmp2);
                    tmp.remove();
                } else {
                    target.createVariant(tmp.getValue(), tmp.getDatatype(), tmp.getScope());
                }
            }
        },

        moveReifier: function (source, target) {
            var r1, r2;
            if (source.getReifier() === null) {
                return;
            } else if (target.getReifier() === null) {
                target.setReifier(source.getReifier());
            } else {
                r1 = source.getReifier();
                r2 = target.getReifier();
                source.setReifier(null);
                r1.mergeIn(r2);
            }
        },

        moveRoleCharacteristics: function (source, target) {
            var i, roles, sigs = new Hash();
            roles = target.getRoles();
            for (i = 0; i < roles.length; i += 1) {
                sigs.put(roles[i], SignatureGenerator.makeRoleSignature(roles[i]));
            }
            roles = source.getRoles();
            for (i = 0; i < roles.length; i += 1) {
                MergeHelper.moveItemIdentifiers(roles[i],
                    sigs.get(SignatureGenerator.makeRoleSignature(roles[i])));
                roles[i].remove();
            }
        },

        moveConstructCharacteristics: function (source, target) {
            MergeHelper.moveReifier(source, target);
            MergeHelper.moveItemIdentifiers(source, target);
        }
    };

    CopyHelper = {
        copyAssociations: function (source, target, mergeMap) {
        },
        copyItemIdentifiers: function (source, target) {
        },
        copyReifier: function (source, target, mergeMap) {
        },
        copyScope: function (source, target, mergeMap) {
        },
        copyTopicMap: function (source, target) {
        },
        copyTopic: function (sourcetm, targettm, mergeMap) {
        },
        copyType: function (source, target, mergeMap) {
        }
    };

    TypeInstanceHelper = {
        convertAssociationsToType: function (tm) {
            var typeInstance, type, instance, associations, index, i, ass, roles;
            typeInstance = tm.getTopicBySubjectIdentifier(
                tm.createLocator(TMDM.TYPE_INSTANCE));
            type = tm.getTopicBySubjectIdentifier(
                tm.createLocator(TMDM.TYPE));
            instance = tm.getTopicBySubjectIdentifier(
                tm.createLocator(TMDM.INSTANCE));
            if (!typeInstance || !type || !instance) {
                return;
            }
            index = tm.getIndex('TypeInstanceIndex');
            if (!index) {
                return;
            }
            if (!index.isAutoUpdated()) {
                index.reindex();
            }
            associations = index.getAssociations(typeInstance);
            for (i = 0; i < associations.length; i += 1) {
                ass = associations[i];
                if (ass.getScope().length > 0 ||
                    ass.getReifier() !== null ||
                    ass.getItemIdentifiers().length > 0) {
                    continue;
                }
                roles = ass.getRoles();
                if (roles.length !== 2) {
                    continue;
                }
                if (roles[0].getType().equals(type) && roles[1].getType().equals(instance)) {
                    roles[1].getPlayer().addType(roles[0].getPlayer());
                } else
                if (roles[1].getType().equals(type) && roles[0].getType().equals(instance)) {
                    roles[0].getPlayer().addType(roles[1].getPlayer());
                } else {
                    continue;
                }
                ass.remove();
            }
        }
    };

    // Export objects into the TM namespace
    return {
        TopicMapSystemFactory: TopicMapSystemFactory,
        XSD: XSD,
        TMDM: TMDM,
        Hash: Hash, // needed by CXTM export
        Version: Version
    };
}());

// Pollute the global namespace
TopicMapSystemFactory = TM.TopicMapSystemFactory; 

// Check if we are in a CommonJS environment (e.g. node.js)
if (typeof exports === 'object' && exports !== null) {
    exports.TopicMapSystemFactory = TopicMapSystemFactory;
    exports.TM = TM;
}

/*jslint browser: true, devel: true, onevar: true, undef: true, nomen: false, eqeqeq: true, plusplus: true, bitwise: true,
  regexp: true, newcap: true, immed: true, indent: 4 */
/*global TM, window, DOMParser, ActiveXObject*/ 

TM.JTM = (function () {
    var ReaderImpl, WriterImpl;

    ReaderImpl = function (tm) {
        var that = this;
        this.tm = tm;
        this.version = null; // Keep the JTM version number
        this.prefixes = {};
        this.defaultDatatype = this.tm.createLocator(TM.XSD.string);

        this.curieToLocator = function (loc) {
            var curie, prefix, pos;
            if (that.version === '1.1' &&
                loc.substr(0, 1) === '[') {
                if (loc.substr(loc.length - 1, 1) !== ']') {
                    throw {name: 'InvalidFormat',
                        message: 'Invaild CURIE: missing tailing bracket'};
                }
                curie = loc.substr(1, loc.length - 2);
                pos = curie.indexOf(':');
                if (pos !== -1) {
                    // Lookup prefix and replace with URL
                    prefix = curie.substr(0, pos);
                    if (that.prefixes[prefix]) {
                        loc = that.prefixes[prefix] +
                            curie.substr(pos + 1, curie.length - 1);
                        return loc;
                    } else {
                        throw {name: 'InvalidFormat',
                            message: 'Missing prefix declaration: ' + prefix};
                    }
                } else {
                    throw {name: 'InvalidFormat',
                        message: 'Invaild CURIE: missing colon'};
                }
            }
            return loc;
        };

        /**
        * Internal function that takes a JTM-identifier string as a parameter
        * and returns a topic object - either an existing topic or a new topic
        * if the requested topic did not exist
        * @param {String} locator JTM-identifier
        * @throws {InvalidFormat} If the locator could not be parsed.
        */
        this.getTopicByReference = function (locator) {
            if (typeof locator === 'undefined' || locator === null) {
                return null;
            }
            switch (locator.substr(0, 3)) {
            case 'si:' :
                return this.tm.createTopicBySubjectIdentifier(
                    this.tm.createLocator(this.curieToLocator(locator.substr(3))));
            case 'sl:' :
                return this.tm.createTopicBySubjectLocator(
                    this.tm.createLocator(this.curieToLocator(locator.substr(3))));
            case 'ii:' :
                return this.tm.createTopicByItemIdentifier(
                    this.tm.createLocator(this.curieToLocator(locator.substr(3))));
            }
            throw {name: 'InvalidFormat',
                message: 'Invaild topic reference \'' + locator + '\''};
        };
    };

    /**
    * Imports a JTM topic map or JTM fragment from a JSON-string.
    * name, variant, occurrence and role fragments need the optional parent
    * construct as a parameter.
    * TODO: Decide if this should be part of tmjs. Add functions for decoding/
    * encoding JSON if so.
    *
    * @param {String} str JSON encoded JTM
    * @param {Construct} [parent] Parent construct if the JTM fragment contains
    *        a name, variant, occurrence or role.
    */
    ReaderImpl.prototype.fromString = function (str, parent) {
        var obj = JSON.parse(str);
        return this.fromObject(obj);
    };

    /**
    * Imports a JTM topic map or JTM fragment.
    * name, variant, occurrence and role fragments need the parent construct
    * as a parameter.
    *
    * @param {object} obj with JTM properties
    * @param {Construct} [parent] Parent construct if the JTM fragment contains
    *        a name, variant, occurrence or role.
    */
    ReaderImpl.prototype.fromObject = function (obj, parent) {
        var ret;
        parent = parent || null;
        if (obj.version !== '1.0' && obj.version !== '1.1') {
            throw {name: 'InvalidFormat',
                message: 'Unknown version of JTM: ' + obj.version};
        }
        this.version = obj.version;
        if (obj.version === '1.1' && obj.prefixes) {
            this.prefixes = obj.prefixes;
            // Check if xsd is defined and if it is valid:
            if (obj.prefixes && obj.prefixes.xsd &&
                obj.prefixes.xsd !== 'http://www.w3.org/2001/XMLSchema#') {
                throw {name: 'InvalidFormat',
                    message: 'The XSD prefix MUST have the value "http://www.w3.org/2001/XMLSchema#"'};
            }
        } else if (obj.prefixes) {
            throw {name: 'InvalidFormat',
                message: 'Prefixes are invalid in JTM 1.0: ' + obj.version};
        }
        if (!this.prefixes.xsd) {
            this.prefixes.xsd = 'http://www.w3.org/2001/XMLSchema#';
        }
        if (!obj.item_type) {
            throw {name: 'InvalidFormat',
                message: 'Missing item_type'};
        }
        switch (obj.item_type.toLowerCase()) {
        case "topicmap":
            ret = this.parseTopicMap(obj);
            break;
        case "topic":
            ret = this.parseTopic(obj);
            break;
        case "name":
            ret = this.parseName(parent, obj);
            break;
        case "variant":
            ret = this.parseVariant(parent, obj);
            break;
        case "occurrence":
            ret = this.parseOccurrence(parent, obj);
            break;
        case "association":
            ret = this.parseAssociation(obj);
            break;
        case "role":
            ret = this.parseRole(parent, obj);
            break;
        default:
            throw {name: 'InvalidFormat',
                message: 'Unknown item_type property'};
        }
        return ret;
    };

    /**
     * FIXME: Work in progress. We have to specify *how* the information
     * item can be created.
     *
     * Internal function that parses a parent field. From the JTM spec:
     * "The value of the parent member is an array of item identifiers,
     * each prefixed by "ii:". For occurrences and names the parent array
     * may as well contain subject identifiers prefixed by "si:" and
     * subject locators prefixed by "sl:".
     */
    ReaderImpl.prototype.parseParentAsTopic = function (obj, allowTopic) {
        var parent = null, tmp, i;
        if (!obj.parent) {
            parent = this.tm.createTopic();
        } else if (!(obj.parent instanceof Array) || obj.parent.length === 0) {
            throw {name: 'InvalidFormat',
                message: 'Missing parent topic reference in occurrence'};
        }
        if (obj.parent) {
            for (i = 0; i < obj.parent.length; i += 1) {
                tmp = this.getTopicByReference(obj.parent[i]);
                if (!parent) {
                    parent = tmp;
                } else {
                    parent.mergeIn(tmp);
                }
            }
        }
        return parent;
    };

    ReaderImpl.prototype.parseTopicMap = function (obj) {
        var i, len, arr;
        this.parseItemIdentifiers(this.tm, obj.item_identifiers);
        this.parseReifier(this.tm, obj.reifier);
        if (obj.topics && typeof obj.topics === 'object' && obj.topics instanceof Array) {
            arr = obj.topics;
            len = arr.length;
            for (i = 0; i < len; i += 1) {
                this.parseTopic(arr[i]);
            }
            arr = null;
        }
        if (obj.associations && typeof obj.associations === 'object' &&
            obj.associations instanceof Array) {
            arr = obj.associations;
            len = arr.length;
            for (i = 0; i < len; i += 1) {
                this.parseAssociation(arr[i]);
            }
            arr = null;
        }
        this.tm.sanitize(); // remove duplicates and convert type-instance associations to types
        return true;
    };

    ReaderImpl.prototype.parseTopic = function (obj) {
        var that = this, topic = null, parseIdentifier, arr, i, identifier, type;
        parseIdentifier = function (tm, topic, arr, getFunc, createFunc, addFunc) {
            var i, len, tmp;
            if (arr && typeof arr === 'object' && arr instanceof Array) {
                len = arr.length;
                for (i = 0; i < len; i += 1) {
                    identifier = decodeURI(that.curieToLocator(arr[i]));
                    if (!topic) {
                        topic = createFunc.apply(tm, [tm.createLocator(identifier)]);
                    } else {
                        tmp = getFunc.apply(tm, [tm.createLocator(identifier)]);
                        if (tmp && tmp.isTopic() && !topic.equals(tmp)) {
                            topic.mergeIn(tmp);
                        } else if (!(tmp && tmp.isTopic() && topic.equals(tmp))) {
                            topic[addFunc](tm.createLocator(identifier));
                        }
                    }
                }
            }
            return topic;
        };
        topic = parseIdentifier(this.tm, topic, obj.subject_identifiers,
            this.tm.getTopicBySubjectIdentifier,
            this.tm.createTopicBySubjectIdentifier, 'addSubjectIdentifier');
        topic = parseIdentifier(this.tm, topic, obj.subject_locators,
            this.tm.getTopicBySubjectLocator,
            this.tm.createTopicBySubjectLocator, 'addSubjectLocator');
        topic = parseIdentifier(this.tm, topic, obj.item_identifiers,
            this.tm.getConstructByItemIdentifier,
            this.tm.createTopicByItemIdentifier, 'addItemIdentifier');

        if ((arr = obj.instance_of) && this.version === '1.1') {
            for (i = 0; i < arr.length; i += 1) {
                type = this.getTopicByReference(arr[i]);
                topic.addType(type);
            }
        } else if (obj.instance_of && this.version === '1.0') {
            throw {name: 'InvalidFormat',
                message: 'instance_of is invalid in JTM 1.0'};
        }

        arr = obj.names;
        if (arr && typeof arr === 'object' && arr instanceof Array) {
            for (i = 0; i < arr.length; i += 1) {
                this.parseName(topic, arr[i]);
            }
        }
        arr = obj.occurrences;
        if (arr && typeof arr === 'object' && arr instanceof Array) {
            for (i = 0; i < arr.length; i += 1) {
                this.parseOccurrence(topic, arr[i]);
            }
        }
    };

    ReaderImpl.prototype.parseName = function (parent, obj) {
        var name, type, scope, arr, i;
        if (!parent) {
            parent = this.parseParentAsTopic(obj);
        }
        scope = this.parseScope(obj.scope);
        type = this.getTopicByReference(obj.type);
        name = parent.createName(obj.value, type, scope);
        arr = obj.variants;
        if (arr && typeof arr === 'object' && arr instanceof Array) {
            for (i = 0; i < arr.length; i += 1) {
                this.parseVariant(name, arr[i]);
            }
        }
        this.parseItemIdentifiers(name, obj.item_identifiers);
        this.parseReifier(name, obj.reifier);
    };

    ReaderImpl.prototype.parseVariant = function (parent, obj) {
        var variant, scope;
        scope = this.parseScope(obj.scope);
        variant = parent.createVariant(obj.value, 
            obj.datatype ?
                this.tm.createLocator(this.curieToLocator(obj.datatype)) :
                    this.defaultDatatype, scope);
        this.parseItemIdentifiers(variant, obj.item_identifiers);
        this.parseReifier(variant, obj.reifier);
    };

    ReaderImpl.prototype.parseOccurrence = function (parent, obj) {
        var occurrence, type, scope;
        if (!parent) {
            parent = this.parseParentAsTopic(obj);
        }
        scope = this.parseScope(obj.scope);
        type = this.getTopicByReference(obj.type);
        occurrence = parent.createOccurrence(type, obj.value,
            obj.datatype ?
                this.tm.createLocator(this.curieToLocator(obj.datatype)) :
                    this.defaultDatatype, scope);
        this.parseItemIdentifiers(occurrence, obj.item_identifiers);
        this.parseReifier(occurrence, obj.reifier);
    };

    ReaderImpl.prototype.parseAssociation = function (obj) {
        var association, type, scope, arr, i;
        scope = this.parseScope(obj.scope);
        type = this.getTopicByReference(obj.type);
        association = this.tm.createAssociation(type, scope);
        arr = obj.roles;
        if (arr && typeof arr === 'object' && arr instanceof Array) {
            if (arr.length === 0) {
                throw {name: 'InvalidFormat',
                    message: 'Association needs roles'};
            }
            for (i = 0; i < arr.length; i += 1) {
                this.parseRole(association, arr[i]);
            }
        } else {
            throw {name: 'InvalidFormat',
                message: 'Association needs roles'};
        }
        this.parseItemIdentifiers(association, obj.item_identifiers);
        this.parseReifier(association, obj.reifier);
    };

    ReaderImpl.prototype.parseRole = function (parent, obj) {
        var role, type, player;
        type = this.getTopicByReference(obj.type);
        player = this.getTopicByReference(obj.player);
        role = parent.createRole(type, player);
        this.parseItemIdentifiers(role, obj.item_identifiers);
        this.parseReifier(role, obj.reifier);
    };

    ReaderImpl.prototype.parseScope = function (arr) {
        var i, scope = [];
        if (arr && typeof arr === 'object' && arr instanceof Array) {
            for (i = 0; i < arr.length; i += 1) {
                scope.push(this.getTopicByReference(arr[i]));
            }
        }
        return scope;
    };


    ReaderImpl.prototype.parseItemIdentifiers = function (construct, arr) {
        var i, tm, identifier;
        tm = construct.getTopicMap();
        if (arr && typeof arr === 'object' && arr instanceof Array) {
            for (i = 0; i < arr.length; i += 1) {
                identifier = this.curieToLocator(arr[i]);
                if (!tm.getConstructByItemIdentifier(tm.createLocator(identifier))) {
                    construct.addItemIdentifier(tm.createLocator(identifier));
                }
            }
        }
    };

    ReaderImpl.prototype.parseReifier = function (construct, reifier) {
        var reifierTopic = this.getTopicByReference(reifier);
        if (reifierTopic && reifierTopic.getReified() === null || !reifierTopic) {
            construct.setReifier(reifierTopic);
        } // else: Ignore the case that reifierTopic reifies another item
    };

    /**
    * @class Exports topic maps constructs as JTM 1.0 JavaScript objects.
    * See http://www.cerny-online.com/jtm/1.0/ for the JSON Topic Maps specification.
    * JSON 1.1 is described at http://www.cerny-online.com/jtm/1.1/
    * @param {String} version Version number of the JTM export. Valid values are '1.0'
    *                 and '1.1'. Version 1.1 produces more compact files. The default
    *                 value is '1.0', but this may change in the future.
    */
    WriterImpl = function (version) {
        var that = this, referenceToCURIEorURI;
        this.defaultDatatype = TM.XSD.string;
        this.prefixes = new TM.Hash();
        this.version = version || '1.0';

        referenceToCURIEorURI = function (reference) {
            var key, keys, i, value;
            if (that.version === '1.0') {
                return reference;
            }
            // TODO Sort keys after descending value length - longest first
            // to find the best prefix
            keys = that.prefixes.keys();
            for (i = 0; i < keys.length; i += 1) {
                key = keys[i];
                value = that.prefixes.get(key);
                if (reference.substring(0, value.length) ===  value) {
                    return '[' + key + ':' +
                        reference.substr(value.length) + ']';
                }
            }
            return reference;
        };  

        /**
        * Sets prefixes for JTM 1.1 export. prefixes is an object with the
        * prefix as key and its corresponding reference as value.
        */
        this.setPrefixes = function (prefixes) {
            var key;
            for (key in prefixes) {
                if (prefixes.hasOwnProperty(key)) {
                    this.prefixes.put(key, prefixes[key]);
                }
            }
        };

        /**
         * Generates a JTM reference based on the topics subject identifier,
         * subject locator or item identifier (whatever is set, tested in this
         * order).
         * @returns {string} Representing the topic t, e.g.
         *     "si:http://psi.topicmaps.org/iso13250/model/type
         */
        this.getTopicReference = function (t) {
            var arr;
            arr = t.getSubjectIdentifiers();
            if (arr.length > 0) {
                return 'si:' + referenceToCURIEorURI(arr[0].getReference());
            }
            arr = t.getSubjectLocators();
            if (arr.length > 0) {
                return 'sl:' + referenceToCURIEorURI(arr[0].getReference());
            }
            arr = t.getItemIdentifiers();
            if (arr.length > 0) {
                return 'ii:' + referenceToCURIEorURI(arr[0].getReference());
            }
            // ModelConstraintExeption: TMDM says that t MUST have on of these
        };

        this.exportIdentifiers = function (obj, arr, attr) {
            var i, len = arr.length;
            if (len > 0) {
                obj[attr] = [];
                for (i = 0; i < len; i += 1) {
                    obj[attr].push(referenceToCURIEorURI(arr[i].getReference()));
                }
            }
        
        }; 

        this.exportScope = function (obj, construct) {
            var i, arr = construct.getScope();
            if (arr.length > 0) {
                obj.scope = [];
                for (i = 0; i < arr.length; i += 1) {
                    obj.scope.push(that.getTopicReference(arr[i]));
                }
            }
        };

        this.exportParent = function (obj, construct) {
            var parent = construct.getParent();
            that.exportIdentifiers(obj, parent.getItemIdentifiers(), 'parent');
        };

        this.exportTopicMap = function (m) {
            var arr, i, len, obj;
            obj = {
                topics: [],
                associations: []
            };
            arr = m.getTopics();
            len = arr.length;
            for (i = 0; i < len; i += 1) {
                obj.topics.push(that.exportTopic(arr[i]));
            }
            arr = m.getAssociations();
            len = arr.length;
            for (i = 0; i < len; i += 1) {
                obj.associations.push(that.exportAssociation(arr[i]));
            }
            return obj;
        };

        this.exportTopic = function (t) {
            var arr, i, len, obj;
            obj = {};
            that.exportIdentifiers(obj, t.getSubjectIdentifiers(), 'subject_identifiers');
            that.exportIdentifiers(obj, t.getSubjectLocators(), 'subject_locators');
            that.exportIdentifiers(obj, t.getItemIdentifiers(), 'item_identifiers');
            arr = t.getNames();
            len = arr.length;
            if (len > 0) {
                obj.names = [];
                for (i = 0; i < len; i += 1) {
                    obj.names.push(that.exportName(arr[i]));
                }
            }
            arr = t.getOccurrences();
            len = arr.length;
            if (len > 0) {
                obj.occurrences = [];
                for (i = 0; i < len; i += 1) {
                    obj.occurrences.push(that.exportOccurrence(arr[i]));
                }
            }
            arr = t.getTypes();
            len = arr.length;
            if (len > 0) {
                obj.instance_of = [];
                for (i = 0; i < len; i += 1) {
                    obj.instance_of.push(that.getTopicReference(arr[i]));
                }
            }
            return obj;
        };

        this.exportName = function (name) {
            var arr, i, len, obj, tmp;
            obj = {
                'value': name.getValue()
            };
            tmp = name.getType();
            if (tmp) {
                obj.type = that.getTopicReference(tmp);
            }
            tmp = name.getReifier();
            if (tmp) {
                obj.reifier = that.getTopicReference(tmp);
            }
            
            that.exportIdentifiers(obj, name.getItemIdentifiers(), 'item_identifiers');
            that.exportScope(obj, name);
            arr = name.getVariants();
            len = arr.length;
            if (len > 0) {
                obj.variants = [];
                for (i = 0; i < len; i += 1) {
                    obj.variants.push(that.exportVariant(arr[i]));
                }
            }
            return obj;
        };

        this.exportVariant = function (variant) {
            var obj, tmp;
            obj = {
                'value': variant.getValue()
            };
            tmp = variant.getDatatype();
            if (tmp && tmp !== variant.getTopicMap().createLocator(that.defaultDatatype)) {
                obj.datatype = referenceToCURIEorURI(tmp.getReference());
            }
            tmp = variant.getReifier();
            if (tmp) {
                obj.reifier = that.getTopicReference(tmp);
            }
            
            that.exportIdentifiers(obj, variant.getItemIdentifiers(), 'item_identifiers');
            that.exportScope(obj, variant);
        };

        this.exportOccurrence = function (occ) {
            var obj, tmp;
            obj = {
                value: occ.getValue(),
                type: that.getTopicReference(occ.getType())
            };
            tmp = occ.getDatatype();
            if (tmp && tmp !== occ.getTopicMap().createLocator(that.defaultDatatype)) {
                obj.datatype = referenceToCURIEorURI(tmp.getReference());
            }
            tmp = occ.getReifier();
            if (tmp) {
                obj.reifier = that.getTopicReference(tmp);
            }
            
            that.exportIdentifiers(obj, occ.getItemIdentifiers(), 'item_identifiers');
            that.exportScope(obj, occ);
            return obj;
        };

        this.exportAssociation = function (association) {
            var arr, i, obj, tmp;
            obj = {
                type: that.getTopicReference(association.getType()),
                roles: []
            };
            tmp = association.getReifier();
            if (tmp) {
                obj.reifier = that.getTopicReference(tmp);
            }
            that.exportIdentifiers(obj, association.getItemIdentifiers(), 'item_identifiers');
            that.exportScope(obj, association);
            arr = association.getRoles();
            for (i = 0; i < arr.length; i += 1) {
                obj.roles.push(that.exportRole(arr[i]));
            }
            return obj;
        };

        this.exportRole = function (role) {
            var obj, tmp;
            obj = {
                player: that.getTopicReference(role.getPlayer()),
                type: that.getTopicReference(role.getType())
            };
            tmp = role.getReifier();
            if (tmp) {
                obj.reifier = that.getTopicReference(tmp);
            }
            that.exportIdentifiers(obj, role.getItemIdentifiers(), 'item_identifiers');
            return obj;
        };
    };

    /**
    * Returns a JTM JavaScript object representation of construct.
    * @param {Construct} construct The topic map construct to be exported. Can be
    * TopicMap, Topic, Occurrence, Name, Variant, Association or Role.
    * @param {boolean} [includeParent] If true the optional JTM element 'parent' is
    * included. Refers to the parent via its item identifier.  If undefined or false,
    * the parent element is dropped.
    */
    WriterImpl.prototype.toObject = function (construct, includeParent) {
        var obj, tm, keys, i;
        includeParent = includeParent || false;
        tm = construct.getTopicMap();

        if (construct.isTopicMap()) {
            obj = this.exportTopicMap(construct);
            obj.item_type = 'topicmap';
        } else if (construct.isRole()) {
            obj = this.exportRole(construct);
            obj.item_type = 'role';
        } else if (construct.isTopic()) {
            obj = this.exportTopic(construct);
            obj.item_type = 'topic';
        } else if (construct.isAssociation()) {
            obj = this.exportAssociation(construct);
            obj.item_type = 'association';
        } else if (construct.isOccurrence()) {
            obj = this.exportOccurrence(construct);
            obj.item_type = 'occurrence';
        } else if (construct.isName()) {
            obj = this.exportName(construct);
            obj.item_type = 'name';
        } else if (construct.isVariant()) {
            obj = this.exportVariant(construct);
            obj.item_type = 'variant';
        }
        obj.version = this.version;
        if (this.version === '1.1' && this.prefixes) {
            if (this.prefixes.size()) {
                keys = this.prefixes.keys();
                obj.prefixes = {};
                for (i = 0; i < keys.length; i += 1) {
                    obj.prefixes[keys[i]] = this.prefixes.get(keys[i]);
                }
            }
        }
        if (!construct.isTopic() && construct.getReifier()) {
            obj.reifier = this.getTopicReference(construct.getReifier());
        }
        if (includeParent && !construct.isTopicMap()) {
            this.exportParent(obj, construct);
        }
        return obj;
    };

    return {
        Reader: ReaderImpl,
        Writer: WriterImpl
    };
}());