The source code

    /**
     * @class Ext.data.Store
     * @extends Ext.util.Observable
     * <p>The Store class encapsulates a client side cache of {@link Ext.data.Record Record}
     * objects which provide input data for Components such as the {@link Ext.grid.GridPanel GridPanel},
     * the {@link Ext.form.ComboBox ComboBox}, or the {@link Ext.DataView DataView}.</p>
     * <p><u>Retrieving Data</u></p>
     * <p>A Store object may access a data object using:<div class="mdetail-params"><ul>
     * <li>{@link #proxy configured implementation} of {@link Ext.data.DataProxy DataProxy}</li>
     * <li>{@link #data} to automatically pass in data</li>
     * <li>{@link #loadData} to manually pass in data</li>
     * </ul></div></p>
     * <p><u>Reading Data</u></p>
     * <p>A Store object has no inherent knowledge of the format of the data object (it could be
     * an Array, XML, or JSON). A Store object uses an appropriate {@link #reader configured implementation}
     * of a {@link Ext.data.DataReader DataReader} to create {@link Ext.data.Record Record} instances from the data
     * object.</p>
     * <p><u>Store Types</u></p>
     * <p>There are several implementations of Store available which are customized for use with
     * a specific DataReader implementation.  Here is an example using an ArrayStore which implicitly
     * creates a reader commensurate to an Array data object.</p>
     * <pre><code>
    var myStore = new Ext.data.ArrayStore({
        fields: ['fullname', 'first'],
        idIndex: 0 // id for each record will be the first element
    });
     * </code></pre>
     * <p>For custom implementations create a basic {@link Ext.data.Store} configured as needed:</p>
     * <pre><code>
    // create a {@link Ext.data.Record Record} constructor:
    var rt = Ext.data.Record.create([
        {name: 'fullname'},
        {name: 'first'}
    ]);
    var myStore = new Ext.data.Store({
        // explicitly create reader
        reader: new Ext.data.ArrayReader(
            {
                idIndex: 0  // id for each record will be the first element
            },
            rt // recordType
        )
    });
     * </code></pre>
     * <p>Load some data into store (note the data object is an array which corresponds to the reader):</p>
     * <pre><code>
    var myData = [
        [1, 'Fred Flintstone', 'Fred'],  // note that id for the record is the first element
        [2, 'Barney Rubble', 'Barney']
    ];
    myStore.loadData(myData);
     * </code></pre>
     * <p>Records are cached and made available through accessor functions.  An example of adding
     * a record to the store:</p>
     * <pre><code>
    var defaultData = {
        fullname: 'Full Name',
        first: 'First Name'
    };
    var recId = 100; // provide unique id for the record
    var r = new myStore.recordType(defaultData, ++recId); // create new record
    myStore.{@link #insert}(0, r); // insert a new record into the store (also see {@link #add})
     * </code></pre>
     * <p><u>Writing Data</u></p>
     * <p>And <b>new in Ext version 3</b>, use the new {@link Ext.data.DataWriter DataWriter} to create an automated, <a href="http://extjs.com/deploy/dev/examples/writer/writer.html">Writable Store</a>
     * along with <a href="http://extjs.com/deploy/dev/examples/restful/restful.html">RESTful features.</a>
     * @constructor
     * Creates a new Store.
     * @param {Object} config A config object containing the objects needed for the Store to access data,
     * and read the data into Records.
     * @xtype store
     */
    Ext.data.Store = Ext.extend(Ext.util.Observable, {
        /**
         * @cfg {String} storeId If passed, the id to use to register with the <b>{@link Ext.StoreMgr StoreMgr}</b>.
         * <p><b>Note</b>: if a (deprecated) <tt>{@link #id}</tt> is specified it will supersede the <tt>storeId</tt>
         * assignment.</p>
         */
        /**
         * @cfg {String} url If a <tt>{@link #proxy}</tt> is not specified the <tt>url</tt> will be used to
         * implicitly configure a {@link Ext.data.HttpProxy HttpProxy} if an <tt>url</tt> is specified.
         * Typically this option, or the <code>{@link #data}</code> option will be specified.
         */
        /**
         * @cfg {Boolean/Object} autoLoad If <tt>{@link #data}</tt> is not specified, and if <tt>autoLoad</tt>
         * is <tt>true</tt> or an <tt>Object</tt>, this store's {@link #load} method is automatically called
         * after creation. If the value of <tt>autoLoad</tt> is an <tt>Object</tt>, this <tt>Object</tt> will
         * be passed to the store's {@link #load} method.
         */
        /**
         * @cfg {Ext.data.DataProxy} proxy The {@link Ext.data.DataProxy DataProxy} object which provides
         * access to a data object.  See <code>{@link #url}</code>.
         */
        /**
         * @cfg {Array} data An inline data object readable by the <code>{@link #reader}</code>.
         * Typically this option, or the <code>{@link #url}</code> option will be specified.
         */
        /**
         * @cfg {Ext.data.DataReader} reader The {@link Ext.data.DataReader Reader} object which processes the
         * data object and returns an Array of {@link Ext.data.Record} objects which are cached keyed by their
         * <b><tt>{@link Ext.data.Record#id id}</tt></b> property.
         */
        /**
         * @cfg {Ext.data.DataWriter} writer
         * <p>The {@link Ext.data.DataWriter Writer} object which processes a record object for being written
         * to the server-side database.</p>
         * <br><p>When a writer is installed into a Store the {@link #add}, {@link #remove}, and {@link #update}
         * events on the store are monitored in order to remotely {@link #createRecords create records},
         * {@link #destroyRecord destroy records}, or {@link #updateRecord update records}.</p>
         * <br><p>The proxy for this store will relay any {@link #writexception} events to this store.</p>
         * <br><p>Sample implementation:
         * <pre><code>
    var writer = new {@link Ext.data.JsonWriter}({
        encode: true,
        writeAllFields: true // write all fields, not just those that changed
    });

    // Typical Store collecting the Proxy, Reader and Writer together.
    var store = new Ext.data.Store({
        storeId: 'user',
        root: 'records',
        proxy: proxy,
        reader: reader,
        writer: writer,     // <-- plug a DataWriter into the store just as you would a Reader
        paramsAsHash: true,
        autoSave: false    // <-- false to delay executing create, update, destroy requests
                            //     until specifically told to do so.
    });
         * </code></pre></p>
         */
        writer : undefined,
        /**
         * @cfg {Object} baseParams
         * <p>An object containing properties which are to be sent as parameters
         * for <i>every</i> HTTP request.</p>
         * <p>Parameters are encoded as standard HTTP parameters using {@link Ext#urlEncode}.</p>
         * <p><b>Note</b>: <code>baseParams</code> may be superseded by any <code>params</code>
         * specified in a <code>{@link #load}</code> request, see <code>{@link #load}</code>
         * for more details.</p>
         * This property may be modified after creation using the <code>{@link #setBaseParam}</code>
         * method.
         */
        /**
         * @cfg {Object} sortInfo A config object to specify the sort order in the request of a Store's
         * {@link #load} operation.  Note that for local sorting, the <tt>direction</tt> property is
         * case-sensitive. See also {@link #remoteSort} and {@link #paramNames}.
         * For example:<pre><code>
    sortInfo: {
        field: 'fieldName',
        direction: 'ASC' // or 'DESC' (case sensitive for local sorting)
    }
    </code></pre>
         */
        /**
         * @cfg {boolean} remoteSort <tt>true</tt> if sorting is to be handled by requesting the <tt>{@link #proxy Proxy}</tt>
         * to provide a refreshed version of the data object in sorted order, as opposed to sorting the Record cache
         * in place (defaults to <tt>false</tt>).
         * <p>If <tt>remoteSort</tt> is <tt>true</tt>, then clicking on a {@link Ext.grid.Column Grid Column}'s
         * {@link Ext.grid.Column#header header} causes the current page to be requested from the server appending
         * the following two parameters to the <b><tt>{@link #load params}</tt></b>:<div class="mdetail-params"><ul>
         * <li><b><tt>sort</tt></b> : String<p class="sub-desc">The <tt>name</tt> (as specified in the Record's
         * {@link Ext.data.Field Field definition}) of the field to sort on.</p></li>
         * <li><b><tt>dir</tt></b> : String<p class="sub-desc">The direction of the sort, 'ASC' or 'DESC' (case-sensitive).</p></li>
         * </ul></div></p>
         */
        remoteSort : false,

        /**
         * @cfg {Boolean} autoDestroy <tt>true</tt> to destroy the store when the component the store is bound
         * to is destroyed (defaults to <tt>false</tt>).
         * <p><b>Note</b>: this should be set to true when using stores that are bound to only 1 component.</p>
         */
        autoDestroy : false,

        /**
         * @cfg {Boolean} pruneModifiedRecords <tt>true</tt> to clear all modified record information each time
         * the store is loaded or when a record is removed (defaults to <tt>false</tt>). See {@link #getModifiedRecords}
         * for the accessor method to retrieve the modified records.
         */
        pruneModifiedRecords : false,

        /**
         * Contains the last options object used as the parameter to the {@link #load} method. See {@link #load}
         * for the details of what this may contain. This may be useful for accessing any params which were used
         * to load the current Record cache.
         * @property
         */
        lastOptions : null,

        /**
         * @cfg {Boolean} autoSave
         * <p>Defaults to <tt>true</tt> causing the store to automatically {@link #save} records to
         * the server when a record is modified (ie: becomes 'dirty'). Specify <tt>false</tt> to manually call {@link #save}
         * to send all modifiedRecords to the server.</p>
         * <br><p><b>Note</b>: each CRUD action will be sent as a separate request.</p>
         */
        autoSave : true,

        /**
         * @cfg {Boolean} batch
         * <p>Defaults to <tt>true</tt> (unless <code>{@link #restful}:true</code>). Multiple
         * requests for each CRUD action (CREATE, READ, UPDATE and DESTROY) will be combined
         * and sent as one transaction. Only applies when <code>{@link #autoSave}</code> is set
         * to <tt>false</tt>.</p>
         * <br><p>If Store is RESTful, the DataProxy is also RESTful, and a unique transaction is
         * generated for each record.</p>
         */
        batch : true,

        /**
         * @cfg {Boolean} restful
         * Defaults to <tt>false</tt>.  Set to <tt>true</tt> to have the Store and the set
         * Proxy operate in a RESTful manner. The store will automatically generate GET, POST,
         * PUT and DELETE requests to the server. The HTTP method used for any given CRUD
         * action is described in {@link Ext.data.Api#restActions}.  For additional information
         * see {@link Ext.data.DataProxy#restful}.
         * <p><b>Note</b>: if <code>{@link #restful}:true</code> <code>batch</code> will
         * internally be set to <tt>false</tt>.</p>
         */
        restful: false,

        /**
         * @cfg {Object} paramNames
         * <p>An object containing properties which specify the names of the paging and
         * sorting parameters passed to remote servers when loading blocks of data. By default, this
         * object takes the following form:</p><pre><code>
    {
        start : 'start',  // The parameter name which specifies the start row
        limit : 'limit',  // The parameter name which specifies number of rows to return
        sort : 'sort',    // The parameter name which specifies the column to sort on
        dir : 'dir'       // The parameter name which specifies the sort direction
    }
    </code></pre>
         * <p>The server must produce the requested data block upon receipt of these parameter names.
         * If different parameter names are required, this property can be overriden using a configuration
         * property.</p>
         * <p>A {@link Ext.PagingToolbar PagingToolbar} bound to this Store uses this property to determine
         * the parameter names to use in its {@link #load requests}.
         */
        paramNames : undefined,

        /**
         * @cfg {Object} defaultParamNames
         * Provides the default values for the {@link #paramNames} property. To globally modify the parameters
         * for all stores, this object should be changed on the store prototype.
         */
        defaultParamNames : {
            start : 'start',
            limit : 'limit',
            sort : 'sort',
            dir : 'dir'
        },

        isDestroyed: false,
        hasMultiSort: false,

        // private
        batchKey : '_ext_batch_',

        constructor : function(config){
            /**
             * @property hasMultiSort
             * @type Boolean
             * True if this store is currently sorted by more than one field/direction combination.
             */

            /**
             * @property isDestroyed
             * @type Boolean
             * True if the store has been destroyed already. Read only
             */

            this.data = new Ext.util.MixedCollection(false);
            this.data.getKey = function(o){
                return o.id;
            };

            // temporary removed-records cache
            this.removed = [];

            if(config && config.data){
                this.inlineData = config.data;
                delete config.data;
            }

            Ext.apply(this, config);

            /**
             * See the <code>{@link #baseParams corresponding configuration option}</code>
             * for a description of this property.
             * To modify this property see <code>{@link #setBaseParam}</code>.
             * @property
             */
            this.baseParams = Ext.isObject(this.baseParams) ? this.baseParams : {};

            this.paramNames = Ext.applyIf(this.paramNames || {}, this.defaultParamNames);

            if((this.url || this.api) && !this.proxy){
                this.proxy = new Ext.data.HttpProxy({url: this.url, api: this.api});
            }
            // If Store is RESTful, so too is the DataProxy
            if (this.restful === true && this.proxy) {
                // When operating RESTfully, a unique transaction is generated for each record.
                // TODO might want to allow implemention of faux REST where batch is possible using RESTful routes only.
                this.batch = false;
                Ext.data.Api.restify(this.proxy);
            }

            if(this.reader){ // reader passed
                if(!this.recordType){
                    this.recordType = this.reader.recordType;
                }
                if(this.reader.onMetaChange){
                    this.reader.onMetaChange = this.reader.onMetaChange.createSequence(this.onMetaChange, this);
                }
                if (this.writer) { // writer passed
                    if (this.writer instanceof(Ext.data.DataWriter) === false) {    // <-- config-object instead of instance.
                        this.writer = this.buildWriter(this.writer);
                    }
                    this.writer.meta = this.reader.meta;
                    this.pruneModifiedRecords = true;
                }
            }

            /**
             * The {@link Ext.data.Record Record} constructor as supplied to (or created by) the
             * {@link Ext.data.DataReader Reader}. Read-only.
             * <p>If the Reader was constructed by passing in an Array of {@link Ext.data.Field} definition objects,
             * instead of a Record constructor, it will implicitly create a Record constructor from that Array (see
             * {@link Ext.data.Record}.{@link Ext.data.Record#create create} for additional details).</p>
             * <p>This property may be used to create new Records of the type held in this Store, for example:</p><pre><code>
        // create the data store
        var store = new Ext.data.ArrayStore({
            autoDestroy: true,
            fields: [
               {name: 'company'},
               {name: 'price', type: 'float'},
               {name: 'change', type: 'float'},
               {name: 'pctChange', type: 'float'},
               {name: 'lastChange', type: 'date', dateFormat: 'n/j h:ia'}
            ]
        });
        store.loadData(myData);

        // create the Grid
        var grid = new Ext.grid.EditorGridPanel({
            store: store,
            colModel: new Ext.grid.ColumnModel({
                columns: [
                    {id:'company', header: 'Company', width: 160, dataIndex: 'company'},
                    {header: 'Price', renderer: 'usMoney', dataIndex: 'price'},
                    {header: 'Change', renderer: change, dataIndex: 'change'},
                    {header: '% Change', renderer: pctChange, dataIndex: 'pctChange'},
                    {header: 'Last Updated', width: 85,
                        renderer: Ext.util.Format.dateRenderer('m/d/Y'),
                        dataIndex: 'lastChange'}
                ],
                defaults: {
                    sortable: true,
                    width: 75
                }
            }),
            autoExpandColumn: 'company', // match the id specified in the column model
            height:350,
            width:600,
            title:'Array Grid',
            tbar: [{
                text: 'Add Record',
                handler : function(){
                    var defaultData = {
                        change: 0,
                        company: 'New Company',
                        lastChange: (new Date()).clearTime(),
                        pctChange: 0,
                        price: 10
                    };
                    var recId = 3; // provide unique id
                    var p = new store.recordType(defaultData, recId); // create new record
                    grid.stopEditing();
                    store.{@link #insert}(0, p); // insert a new record into the store (also see {@link #add})
                    grid.startEditing(0, 0);
                }
            }]
        });
             * </code></pre>
             * @property recordType
             * @type Function
             */

            if(this.recordType){
                /**
                 * A {@link Ext.util.MixedCollection MixedCollection} containing the defined {@link Ext.data.Field Field}s
                 * for the {@link Ext.data.Record Records} stored in this Store. Read-only.
                 * @property fields
                 * @type Ext.util.MixedCollection
                 */
                this.fields = this.recordType.prototype.fields;
            }
            this.modified = [];

            this.addEvents(
                /**
                 * @event datachanged
                 * Fires when the data cache has changed in a bulk manner (e.g., it has been sorted, filtered, etc.) and a
                 * widget that is using this Store as a Record cache should refresh its view.
                 * @param {Store} this
                 */
                'datachanged',
                /**
                 * @event metachange
                 * Fires when this store's reader provides new metadata (fields). This is currently only supported for JsonReaders.
                 * @param {Store} this
                 * @param {Object} meta The JSON metadata
                 */
                'metachange',
                /**
                 * @event add
                 * Fires when Records have been {@link #add}ed to the Store
                 * @param {Store} this
                 * @param {Ext.data.Record[]} records The array of Records added
                 * @param {Number} index The index at which the record(s) were added
                 */
                'add',
                /**
                 * @event remove
                 * Fires when a Record has been {@link #remove}d from the Store
                 * @param {Store} this
                 * @param {Ext.data.Record} record The Record that was removed
                 * @param {Number} index The index at which the record was removed
                 */
                'remove',
                /**
                 * @event update
                 * Fires when a Record has been updated
                 * @param {Store} this
                 * @param {Ext.data.Record} record The Record that was updated
                 * @param {String} operation The update operation being performed.  Value may be one of:
                 * <pre><code>
         Ext.data.Record.EDIT
         Ext.data.Record.REJECT
         Ext.data.Record.COMMIT
                 * </code></pre>
                 */
                'update',
                /**
                 * @event clear
                 * Fires when the data cache has been cleared.
                 * @param {Store} this
                 * @param {Record[]} records The records that were cleared.
                 */
                'clear',
                /**
                 * @event exception
                 * <p>Fires if an exception occurs in the Proxy during a remote request.
                 * This event is relayed through the corresponding {@link Ext.data.DataProxy}.
                 * See {@link Ext.data.DataProxy}.{@link Ext.data.DataProxy#exception exception}
                 * for additional details.
                 * @param {misc} misc See {@link Ext.data.DataProxy}.{@link Ext.data.DataProxy#exception exception}
                 * for description.
                 */
                'exception',
                /**
                 * @event beforeload
                 * Fires before a request is made for a new data object.  If the beforeload handler returns
                 * <tt>false</tt> the {@link #load} action will be canceled.
                 * @param {Store} this
                 * @param {Object} options The loading options that were specified (see {@link #load} for details)
                 */
                'beforeload',
                /**
                 * @event load
                 * Fires after a new set of Records has been loaded.
                 * @param {Store} this
                 * @param {Ext.data.Record[]} records The Records that were loaded
                 * @param {Object} options The loading options that were specified (see {@link #load} for details)
                 */
                'load',
                /**
                 * @event loadexception
                 * <p>This event is <b>deprecated</b> in favor of the catch-all <b><code>{@link #exception}</code></b>
                 * event instead.</p>
                 * <p>This event is relayed through the corresponding {@link Ext.data.DataProxy}.
                 * See {@link Ext.data.DataProxy}.{@link Ext.data.DataProxy#loadexception loadexception}
                 * for additional details.
                 * @param {misc} misc See {@link Ext.data.DataProxy}.{@link Ext.data.DataProxy#loadexception loadexception}
                 * for description.
                 */
                'loadexception',
                /**
                 * @event beforewrite
                 * @param {Ext.data.Store} store
                 * @param {String} action [Ext.data.Api.actions.create|update|destroy]
                 * @param {Record/Record[]} rs The Record(s) being written.
                 * @param {Object} options The loading options that were specified. Edit <code>options.params</code> to add Http parameters to the request.  (see {@link #save} for details)
                 * @param {Object} arg The callback's arg object passed to the {@link #request} function
                 */
                'beforewrite',
                /**
                 * @event write
                 * Fires if the server returns 200 after an Ext.data.Api.actions CRUD action.
                 * Success of the action is determined in the <code>result['successProperty']</code>property (<b>NOTE</b> for RESTful stores,
                 * a simple 20x response is sufficient for the actions "destroy" and "update".  The "create" action should should return 200 along with a database pk).
                 * @param {Ext.data.Store} store
                 * @param {String} action [Ext.data.Api.actions.create|update|destroy]
                 * @param {Object} result The 'data' picked-out out of the response for convenience.
                 * @param {Ext.Direct.Transaction} res
                 * @param {Record/Record[]} rs Store's records, the subject(s) of the write-action
                 */
                'write',
                /**
                 * @event beforesave
                 * Fires before a save action is called. A save encompasses destroying records, updating records and creating records.
                 * @param {Ext.data.Store} store
                 * @param {Object} data An object containing the data that is to be saved. The object will contain a key for each appropriate action,
                 * with an array of records for each action.
                 */
                'beforesave',
                /**
                 * @event save
                 * Fires after a save is completed. A save encompasses destroying records, updating records and creating records.
                 * @param {Ext.data.Store} store
                 * @param {Number} batch The identifier for the batch that was saved.
                 * @param {Object} data An object containing the data that is to be saved. The object will contain a key for each appropriate action,
                 * with an array of records for each action.
                 */
                'save'

            );

            if(this.proxy){
                // TODO remove deprecated loadexception with ext-3.0.1
                this.relayEvents(this.proxy,  ['loadexception', 'exception']);
            }
            // With a writer set for the Store, we want to listen to add/remove events to remotely create/destroy records.
            if (this.writer) {
                this.on({
                    scope: this,
                    add: this.createRecords,
                    remove: this.destroyRecord,
                    update: this.updateRecord,
                    clear: this.onClear
                });
            }

            this.sortToggle = {};
            if(this.sortField){
                this.setDefaultSort(this.sortField, this.sortDir);
            }else if(this.sortInfo){
                this.setDefaultSort(this.sortInfo.field, this.sortInfo.direction);
            }

            Ext.data.Store.superclass.constructor.call(this);

            if(this.id){
                this.storeId = this.id;
                delete this.id;
            }
            if(this.storeId){
                Ext.StoreMgr.register(this);
            }
            if(this.inlineData){
                this.loadData(this.inlineData);
                delete this.inlineData;
            }else if(this.autoLoad){
                this.load.defer(10, this, [
                    typeof this.autoLoad == 'object' ?
                        this.autoLoad : undefined]);
            }
            // used internally to uniquely identify a batch
            this.batchCounter = 0;
            this.batches = {};
        },

        /**
         * builds a DataWriter instance when Store constructor is provided with a writer config-object instead of an instace.
         * @param {Object} config Writer configuration
         * @return {Ext.data.DataWriter}
         * @private
         */
        buildWriter : function(config) {
            var klass = undefined,
                type = (config.format || 'json').toLowerCase();
            switch (type) {
                case 'json':
                    klass = Ext.data.JsonWriter;
                    break;
                case 'xml':
                    klass = Ext.data.XmlWriter;
                    break;
                default:
                    klass = Ext.data.JsonWriter;
            }
            return new klass(config);
        },

        /**
         * Destroys the store.
         */
        destroy : function(){
            if(!this.isDestroyed){
                if(this.storeId){
                    Ext.StoreMgr.unregister(this);
                }
                this.clearData();
                this.data = null;
                Ext.destroy(this.proxy);
                this.reader = this.writer = null;
                this.purgeListeners();
                this.isDestroyed = true;
            }
        },

        /**
         * Add Records to the Store and fires the {@link #add} event.  To add Records
         * to the store from a remote source use <code>{@link #load}({add:true})</code>.
         * See also <code>{@link #recordType}</code> and <code>{@link #insert}</code>.
         * @param {Ext.data.Record[]} records An Array of Ext.data.Record objects
         * to add to the cache. See {@link #recordType}.
         */
        add : function(records) {
            var i, len, record, index;

            records = [].concat(records);
            if (records.length < 1) {
                return;
            }

            for (i = 0, len = records.length; i < len; i++) {
                record = records[i];

                record.join(this);

                if (record.dirty || record.phantom) {
                    this.modified.push(record);
                }
            }

            index = this.data.length;
            this.data.addAll(records);

            if (this.snapshot) {
                this.snapshot.addAll(records);
            }

            this.fireEvent('add', this, records, index);
        },

        /**
         * (Local sort only) Inserts the passed Record into the Store at the index where it
         * should go based on the current sort information.
         * @param {Ext.data.Record} record
         */
        addSorted : function(record){
            var index = this.findInsertIndex(record);
            this.insert(index, record);
        },

        /**
         * @private
         * Update a record within the store with a new reference
         */
        doUpdate: function(rec){
            var id = rec.id;
            // unjoin the old record
            this.getById(id).join(null);

            this.data.replace(id, rec);
            if (this.snapshot) {
                this.snapshot.replace(id, rec);
            }
            rec.join(this);
            this.fireEvent('update', this, rec, Ext.data.Record.COMMIT);
        },

        /**
         * Remove Records from the Store and fires the {@link #remove} event.
         * @param {Ext.data.Record/Ext.data.Record[]} record The record object or array of records to remove from the cache.
         */
        remove : function(record){
            if(Ext.isArray(record)){
                Ext.each(record, function(r){
                    this.remove(r);
                }, this);
                return;
            }
            var index = this.data.indexOf(record);
            if(index > -1){
                record.join(null);
                this.data.removeAt(index);
            }
            if(this.pruneModifiedRecords){
                this.modified.remove(record);
            }
            if(this.snapshot){
                this.snapshot.remove(record);
            }
            if(index > -1){
                this.fireEvent('remove', this, record, index);
            }
        },

        /**
         * Remove a Record from the Store at the specified index. Fires the {@link #remove} event.
         * @param {Number} index The index of the record to remove.
         */
        removeAt : function(index){
            this.remove(this.getAt(index));
        },

        /**
         * Remove all Records from the Store and fires the {@link #clear} event.
         * @param {Boolean} silent [false] Defaults to <tt>false</tt>.  Set <tt>true</tt> to not fire clear event.
         */
        removeAll : function(silent){
            var items = [];
            this.each(function(rec){
                items.push(rec);
            });
            this.clearData();
            if(this.snapshot){
                this.snapshot.clear();
            }
            if(this.pruneModifiedRecords){
                this.modified = [];
            }
            if (silent !== true) {  // <-- prevents write-actions when we just want to clear a store.
                this.fireEvent('clear', this, items);
            }
        },

        // private
        onClear: function(store, records){
            Ext.each(records, function(rec, index){
                this.destroyRecord(this, rec, index);
            }, this);
        },

        /**
         * Inserts Records into the Store at the given index and fires the {@link #add} event.
         * See also <code>{@link #add}</code> and <code>{@link #addSorted}</code>.
         * @param {Number} index The start index at which to insert the passed Records.
         * @param {Ext.data.Record[]} records An Array of Ext.data.Record objects to add to the cache.
         */
        insert : function(index, records) {
            var i, len, record;

            records = [].concat(records);
            for (i = 0, len = records.length; i < len; i++) {
                record = records[i];

                this.data.insert(index + i, record);
                record.join(this);

                if (record.dirty || record.phantom) {
                    this.modified.push(record);
                }
            }

            if (this.snapshot) {
                this.snapshot.addAll(records);
            }

            this.fireEvent('add', this, records, index);
        },

        /**
         * Get the index within the cache of the passed Record.
         * @param {Ext.data.Record} record The Ext.data.Record object to find.
         * @return {Number} The index of the passed Record. Returns -1 if not found.
         */
        indexOf : function(record){
            return this.data.indexOf(record);
        },

        /**
         * Get the index within the cache of the Record with the passed id.
         * @param {String} id The id of the Record to find.
         * @return {Number} The index of the Record. Returns -1 if not found.
         */
        indexOfId : function(id){
            return this.data.indexOfKey(id);
        },

        /**
         * Get the Record with the specified id.
         * @param {String} id The id of the Record to find.
         * @return {Ext.data.Record} The Record with the passed id. Returns undefined if not found.
         */
        getById : function(id){
            return (this.snapshot || this.data).key(id);
        },

        /**
         * Get the Record at the specified index.
         * @param {Number} index The index of the Record to find.
         * @return {Ext.data.Record} The Record at the passed index. Returns undefined if not found.
         */
        getAt : function(index){
            return this.data.itemAt(index);
        },

        /**
         * Returns a range of Records between specified indices.
         * @param {Number} startIndex (optional) The starting index (defaults to 0)
         * @param {Number} endIndex (optional) The ending index (defaults to the last Record in the Store)
         * @return {Ext.data.Record[]} An array of Records
         */
        getRange : function(start, end){
            return this.data.getRange(start, end);
        },

        // private
        storeOptions : function(o){
            o = Ext.apply({}, o);
            delete o.callback;
            delete o.scope;
            this.lastOptions = o;
        },

        // private
        clearData: function(){
            this.data.each(function(rec) {
                rec.join(null);
            });
            this.data.clear();
        },

        /**
         * <p>Loads the Record cache from the configured <tt>{@link #proxy}</tt> using the configured <tt>{@link #reader}</tt>.</p>
         * <br><p>Notes:</p><div class="mdetail-params"><ul>
         * <li><b><u>Important</u></b>: loading is asynchronous! This call will return before the new data has been
         * loaded. To perform any post-processing where information from the load call is required, specify
         * the <tt>callback</tt> function to be called, or use a {@link Ext.util.Observable#listeners a 'load' event handler}.</li>
         * <li>If using {@link Ext.PagingToolbar remote paging}, the first load call must specify the <tt>start</tt> and <tt>limit</tt>
         * properties in the <code>options.params</code> property to establish the initial position within the
         * dataset, and the number of Records to cache on each read from the Proxy.</li>
         * <li>If using {@link #remoteSort remote sorting}, the configured <code>{@link #sortInfo}</code>
         * will be automatically included with the posted parameters according to the specified
         * <code>{@link #paramNames}</code>.</li>
         * </ul></div>
         * @param {Object} options An object containing properties which control loading options:<ul>
         * <li><b><tt>params</tt></b> :Object<div class="sub-desc"><p>An object containing properties to pass as HTTP
         * parameters to a remote data source. <b>Note</b>: <code>params</code> will override any
         * <code>{@link #baseParams}</code> of the same name.</p>
         * <p>Parameters are encoded as standard HTTP parameters using {@link Ext#urlEncode}.</p></div></li>
         * <li><b>callback</b> : Function<div class="sub-desc"><p>A function to be called after the Records
         * have been loaded. The callback is called after the load event is fired, and is passed the following arguments:<ul>
         * <li>r : Ext.data.Record[] An Array of Records loaded.</li>
         * <li>options : Options object from the load call.</li>
         * <li>success : Boolean success indicator.</li></ul></p></div></li>
         * <li><b>scope</b> : Object<div class="sub-desc"><p>Scope with which to call the callback (defaults
         * to the Store object)</p></div></li>
         * <li><b>add</b> : Boolean<div class="sub-desc"><p>Indicator to append loaded records rather than
         * replace the current cache.  <b>Note</b>: see note for <tt>{@link #loadData}</tt></p></div></li>
         * </ul>
         * @return {Boolean} If the <i>developer</i> provided <tt>{@link #beforeload}</tt> event handler returns
         * <tt>false</tt>, the load call will abort and will return <tt>false</tt>; otherwise will return <tt>true</tt>.
         */
        load : function(options) {
            options = Ext.apply({}, options);
            this.storeOptions(options);
            if(this.sortInfo && this.remoteSort){
                var pn = this.paramNames;
                options.params = Ext.apply({}, options.params);
                options.params[pn.sort] = this.sortInfo.field;
                options.params[pn.dir] = this.sortInfo.direction;
            }
            try {
                return this.execute('read', null, options); // <-- null represents rs.  No rs for load actions.
            } catch(e) {
                this.handleException(e);
                return false;
            }
        },

        /**
         * updateRecord  Should not be used directly.  This method will be called automatically if a Writer is set.
         * Listens to 'update' event.
         * @param {Object} store
         * @param {Object} record
         * @param {Object} action
         * @private
         */
        updateRecord : function(store, record, action) {
            if (action == Ext.data.Record.EDIT && this.autoSave === true && (!record.phantom || (record.phantom && record.isValid()))) {
                this.save();
            }
        },

        /**
         * @private
         * Should not be used directly.  Store#add will call this automatically if a Writer is set
         * @param {Object} store
         * @param {Object} records
         * @param {Object} index
         */
        createRecords : function(store, records, index) {
            var modified = this.modified,
                length   = records.length,
                record, i;

            for (i = 0; i < length; i++) {
                record = records[i];

                if (record.phantom && record.isValid()) {
                    record.markDirty();  // <-- Mark new records dirty (Ed: why?)

                    if (modified.indexOf(record) == -1) {
                        modified.push(record);
                    }
                }
            }
            if (this.autoSave === true) {
                this.save();
            }
        },

        /**
         * Destroys a Record.  Should not be used directly.  It's called by Store#remove if a Writer is set.
         * @param {Store} store this
         * @param {Ext.data.Record} record
         * @param {Number} index
         * @private
         */
        destroyRecord : function(store, record, index) {
            if (this.modified.indexOf(record) != -1) {  // <-- handled already if @cfg pruneModifiedRecords == true
                this.modified.remove(record);
            }
            if (!record.phantom) {
                this.removed.push(record);

                // since the record has already been removed from the store but the server request has not yet been executed,
                // must keep track of the last known index this record existed.  If a server error occurs, the record can be
                // put back into the store.  @see Store#createCallback where the record is returned when response status === false
                record.lastIndex = index;

                if (this.autoSave === true) {
                    this.save();
                }
            }
        },

        /**
         * This method should generally not be used directly.  This method is called internally
         * by {@link #load}, or if a Writer is set will be called automatically when {@link #add},
         * {@link #remove}, or {@link #update} events fire.
         * @param {String} action Action name ('read', 'create', 'update', or 'destroy')
         * @param {Record/Record[]} rs
         * @param {Object} options
         * @throws Error
         * @private
         */
        execute : function(action, rs, options, /* private */ batch) {
            // blow up if action not Ext.data.CREATE, READ, UPDATE, DESTROY
            if (!Ext.data.Api.isAction(action)) {
                throw new Ext.data.Api.Error('execute', action);
            }
            // make sure options has a fresh, new params hash
            options = Ext.applyIf(options||{}, {
                params: {}
            });
            if(batch !== undefined){
                this.addToBatch(batch);
            }
            // have to separate before-events since load has a different signature than create,destroy and save events since load does not
            // include the rs (record resultset) parameter.  Capture return values from the beforeaction into doRequest flag.
            var doRequest = true;

            if (action === 'read') {
                doRequest = this.fireEvent('beforeload', this, options);
                Ext.applyIf(options.params, this.baseParams);
            }
            else {
                // if Writer is configured as listful, force single-record rs to be [{}] instead of {}
                // TODO Move listful rendering into DataWriter where the @cfg is defined.  Should be easy now.
                if (this.writer.listful === true && this.restful !== true) {
                    rs = (Ext.isArray(rs)) ? rs : [rs];
                }
                // if rs has just a single record, shift it off so that Writer writes data as '{}' rather than '[{}]'
                else if (Ext.isArray(rs) && rs.length == 1) {
                    rs = rs.shift();
                }
                // Write the action to options.params
                if ((doRequest = this.fireEvent('beforewrite', this, action, rs, options)) !== false) {
                    this.writer.apply(options.params, this.baseParams, action, rs);
                }
            }
            if (doRequest !== false) {
                // Send request to proxy.
                if (this.writer && this.proxy.url && !this.proxy.restful && !Ext.data.Api.hasUniqueUrl(this.proxy, action)) {
                    options.params.xaction = action;    // <-- really old, probaby unecessary.
                }
                // Note:  Up until this point we've been dealing with 'action' as a key from Ext.data.Api.actions.
                // We'll flip it now and send the value into DataProxy#request, since it's the value which maps to
                // the user's configured DataProxy#api
                // TODO Refactor all Proxies to accept an instance of Ext.data.Request (not yet defined) instead of this looooooong list
                // of params.  This method is an artifact from Ext2.
                this.proxy.request(Ext.data.Api.actions[action], rs, options.params, this.reader, this.createCallback(action, rs, batch), this, options);
            }
            return doRequest;
        },

        /**
         * Saves all pending changes to the store.  If the commensurate Ext.data.Api.actions action is not configured, then
         * the configured <code>{@link #url}</code> will be used.
         * <pre>
         * change            url
         * ---------------   --------------------
         * removed records   Ext.data.Api.actions.destroy
         * phantom records   Ext.data.Api.actions.create
         * {@link #getModifiedRecords modified records}  Ext.data.Api.actions.update
         * </pre>
         * @TODO:  Create extensions of Error class and send associated Record with thrown exceptions.
         * e.g.:  Ext.data.DataReader.Error or Ext.data.Error or Ext.data.DataProxy.Error, etc.
         * @return {Number} batch Returns a number to uniquely identify the "batch" of saves occurring. -1 will be returned
         * if there are no items to save or the save was cancelled.
         */
        save : function() {
            if (!this.writer) {
                throw new Ext.data.Store.Error('writer-undefined');
            }

            var queue = [],
                len,
                trans,
                batch,
                data = {},
                i;
            // DESTROY:  First check for removed records.  Records in this.removed are guaranteed non-phantoms.  @see Store#remove
            if(this.removed.length){
                queue.push(['destroy', this.removed]);
            }

            // Check for modified records. Use a copy so Store#rejectChanges will work if server returns error.
            var rs = [].concat(this.getModifiedRecords());
            if(rs.length){
                // CREATE:  Next check for phantoms within rs.  splice-off and execute create.
                var phantoms = [];
                for(i = rs.length-1; i >= 0; i--){
                    if(rs[i].phantom === true){
                        var rec = rs.splice(i, 1).shift();
                        if(rec.isValid()){
                            phantoms.push(rec);
                        }
                    }else if(!rs[i].isValid()){ // <-- while we're here, splice-off any !isValid real records
                        rs.splice(i,1);
                    }
                }
                // If we have valid phantoms, create them...
                if(phantoms.length){
                    queue.push(['create', phantoms]);
                }

                // UPDATE:  And finally, if we're still here after splicing-off phantoms and !isValid real records, update the rest...
                if(rs.length){
                    queue.push(['update', rs]);
                }
            }
            len = queue.length;
            if(len){
                batch = ++this.batchCounter;
                for(i = 0; i < len; ++i){
                    trans = queue[i];
                    data[trans[0]] = trans[1];
                }
                if(this.fireEvent('beforesave', this, data) !== false){
                    for(i = 0; i < len; ++i){
                        trans = queue[i];
                        this.doTransaction(trans[0], trans[1], batch);
                    }
                    return batch;
                }
            }
            return -1;
        },

        // private.  Simply wraps call to Store#execute in try/catch.  Defers to Store#handleException on error.  Loops if batch: false
        doTransaction : function(action, rs, batch) {
            function transaction(records) {
                try{
                    this.execute(action, records, undefined, batch);
                }catch (e){
                    this.handleException(e);
                }
            }
            if(this.batch === false){
                for(var i = 0, len = rs.length; i < len; i++){
                    transaction.call(this, rs[i]);
                }
            }else{
                transaction.call(this, rs);
            }
        },

        // private
        addToBatch : function(batch){
            var b = this.batches,
                key = this.batchKey + batch,
                o = b[key];

            if(!o){
                b[key] = o = {
                    id: batch,
                    count: 0,
                    data: {}
                };
            }
            ++o.count;
        },

        removeFromBatch : function(batch, action, data){
            var b = this.batches,
                key = this.batchKey + batch,
                o = b[key],
                arr;

            if(o){
                arr = o.data[action] || [];
                o.data[action] = arr.concat(data);
                if(o.count === 1){
                    data = o.data;
                    delete b[key];
                    this.fireEvent('save', this, batch, data);
                }else{
                    --o.count;
                }
            }
        },

        // @private callback-handler for remote CRUD actions
        // Do not override -- override loadRecords, onCreateRecords, onDestroyRecords and onUpdateRecords instead.
        createCallback : function(action, rs, batch) {
            var actions = Ext.data.Api.actions;
            return (action == 'read') ? this.loadRecords : function(data, response, success) {
                // calls: onCreateRecords | onUpdateRecords | onDestroyRecords
                this['on' + Ext.util.Format.capitalize(action) + 'Records'](success, rs, [].concat(data));
                // If success === false here, exception will have been called in DataProxy
                if (success === true) {
                    this.fireEvent('write', this, action, data, response, rs);
                }
                this.removeFromBatch(batch, action, data);
            };
        },

        // Clears records from modified array after an exception event.
        // NOTE:  records are left marked dirty.  Do we want to commit them even though they were not updated/realized?
        // TODO remove this method?
        clearModified : function(rs) {
            if (Ext.isArray(rs)) {
                for (var n=rs.length-1;n>=0;n--) {
                    this.modified.splice(this.modified.indexOf(rs[n]), 1);
                }
            } else {
                this.modified.splice(this.modified.indexOf(rs), 1);
            }
        },

        // remap record ids in MixedCollection after records have been realized.  @see Store#onCreateRecords, @see DataReader#realize
        reMap : function(record) {
            if (Ext.isArray(record)) {
                for (var i = 0, len = record.length; i < len; i++) {
                    this.reMap(record[i]);
                }
            } else {
                delete this.data.map[record._phid];
                this.data.map[record.id] = record;
                var index = this.data.keys.indexOf(record._phid);
                this.data.keys.splice(index, 1, record.id);
                delete record._phid;
            }
        },

        // @protected onCreateRecord proxy callback for create action
        onCreateRecords : function(success, rs, data) {
            if (success === true) {
                try {
                    this.reader.realize(rs, data);
                }
                catch (e) {
                    this.handleException(e);
                    if (Ext.isArray(rs)) {
                        // Recurse to run back into the try {}.  DataReader#realize splices-off the rs until empty.
                        this.onCreateRecords(success, rs, data);
                    }
                }
            }
        },

        // @protected, onUpdateRecords proxy callback for update action
        onUpdateRecords : function(success, rs, data) {
            if (success === true) {
                try {
                    this.reader.update(rs, data);
                } catch (e) {
                    this.handleException(e);
                    if (Ext.isArray(rs)) {
                        // Recurse to run back into the try {}.  DataReader#update splices-off the rs until empty.
                        this.onUpdateRecords(success, rs, data);
                    }
                }
            }
        },

        // @protected onDestroyRecords proxy callback for destroy action
        onDestroyRecords : function(success, rs, data) {
            // splice each rec out of this.removed
            rs = (rs instanceof Ext.data.Record) ? [rs] : [].concat(rs);
            for (var i=0,len=rs.length;i<len;i++) {
                this.removed.splice(this.removed.indexOf(rs[i]), 1);
            }
            if (success === false) {
                // put records back into store if remote destroy fails.
                // @TODO: Might want to let developer decide.
                for (i=rs.length-1;i>=0;i--) {
                    this.insert(rs[i].lastIndex, rs[i]);    // <-- lastIndex set in Store#destroyRecord
                }
            }
        },

        // protected handleException.  Possibly temporary until Ext framework has an exception-handler.
        handleException : function(e) {
            // @see core/Error.js
            Ext.handleError(e);
        },

        /**
         * <p>Reloads the Record cache from the configured Proxy using the configured
         * {@link Ext.data.Reader Reader} and the options from the last load operation
         * performed.</p>
         * <p><b>Note</b>: see the Important note in {@link #load}.</p>
         * @param {Object} options <p>(optional) An <tt>Object</tt> containing
         * {@link #load loading options} which may override the {@link #lastOptions options}
         * used in the last {@link #load} operation. See {@link #load} for details
         * (defaults to <tt>null</tt>, in which case the {@link #lastOptions} are
         * used).</p>
         * <br><p>To add new params to the existing params:</p><pre><code>
    lastOptions = myStore.lastOptions;
    Ext.apply(lastOptions.params, {
        myNewParam: true
    });
    myStore.reload(lastOptions);
         * </code></pre>
         */
        reload : function(options){
            this.load(Ext.applyIf(options||{}, this.lastOptions));
        },

        // private
        // Called as a callback by the Reader during a load operation.
        loadRecords : function(o, options, success){
            var i, len;

            if (this.isDestroyed === true) {
                return;
            }
            if(!o || success === false){
                if(success !== false){
                    this.fireEvent('load', this, [], options);
                }
                if(options.callback){
                    options.callback.call(options.scope || this, [], options, false, o);
                }
                return;
            }
            var r = o.records, t = o.totalRecords || r.length;
            if(!options || options.add !== true){
                if(this.pruneModifiedRecords){
                    this.modified = [];
                }
                for(i = 0, len = r.length; i < len; i++){
                    r[i].join(this);
                }
                if(this.snapshot){
                    this.data = this.snapshot;
                    delete this.snapshot;
                }
                this.clearData();
                this.data.addAll(r);
                this.totalLength = t;
                this.applySort();
                this.fireEvent('datachanged', this);
            }else{
                var toAdd = [],
                    rec,
                    cnt = 0;
                for(i = 0, len = r.length; i < len; ++i){
                    rec = r[i];
                    if(this.indexOfId(rec.id) > -1){
                        this.doUpdate(rec);
                    }else{
                        toAdd.push(rec);
                        ++cnt;
                    }
                }
                this.totalLength = Math.max(t, this.data.length + cnt);
                this.add(toAdd);
            }
            this.fireEvent('load', this, r, options);
            if(options.callback){
                options.callback.call(options.scope || this, r, options, true);
            }
        },

        /**
         * Loads data from a passed data block and fires the {@link #load} event. A {@link Ext.data.Reader Reader}
         * which understands the format of the data must have been configured in the constructor.
         * @param {Object} data The data block from which to read the Records.  The format of the data expected
         * is dependent on the type of {@link Ext.data.Reader Reader} that is configured and should correspond to
         * that {@link Ext.data.Reader Reader}'s <tt>{@link Ext.data.Reader#readRecords}</tt> parameter.
         * @param {Boolean} append (Optional) <tt>true</tt> to append the new Records rather the default to replace
         * the existing cache.
         * <b>Note</b>: that Records in a Store are keyed by their {@link Ext.data.Record#id id}, so added Records
         * with ids which are already present in the Store will <i>replace</i> existing Records. Only Records with
         * new, unique ids will be added.
         */
        loadData : function(o, append){
            var r = this.reader.readRecords(o);
            this.loadRecords(r, {add: append}, true);
        },

        /**
         * Gets the number of cached records.
         * <p>If using paging, this may not be the total size of the dataset. If the data object
         * used by the Reader contains the dataset size, then the {@link #getTotalCount} function returns
         * the dataset size.  <b>Note</b>: see the Important note in {@link #load}.</p>
         * @return {Number} The number of Records in the Store's cache.
         */
        getCount : function(){
            return this.data.length || 0;
        },

        /**
         * Gets the total number of records in the dataset as returned by the server.
         * <p>If using paging, for this to be accurate, the data object used by the {@link #reader Reader}
         * must contain the dataset size. For remote data sources, the value for this property
         * (<tt>totalProperty</tt> for {@link Ext.data.JsonReader JsonReader},
         * <tt>totalRecords</tt> for {@link Ext.data.XmlReader XmlReader}) shall be returned by a query on the server.
         * <b>Note</b>: see the Important note in {@link #load}.</p>
         * @return {Number} The number of Records as specified in the data object passed to the Reader
         * by the Proxy.
         * <p><b>Note</b>: this value is not updated when changing the contents of the Store locally.</p>
         */
        getTotalCount : function(){
            return this.totalLength || 0;
        },

        /**
         * Returns an object describing the current sort state of this Store.
         * @return {Object} The sort state of the Store. An object with two properties:<ul>
         * <li><b>field : String</b><p class="sub-desc">The name of the field by which the Records are sorted.</p></li>
         * <li><b>direction : String</b><p class="sub-desc">The sort order, 'ASC' or 'DESC' (case-sensitive).</p></li>
         * </ul>
         * See <tt>{@link #sortInfo}</tt> for additional details.
         */
        getSortState : function(){
            return this.sortInfo;
        },

        /**
         * @private
         * Invokes sortData if we have sortInfo to sort on and are not sorting remotely
         */
        applySort : function(){
            if ((this.sortInfo || this.multiSortInfo) && !this.remoteSort) {
                this.sortData();
            }
        },

        /**
         * @private
         * Performs the actual sorting of data. This checks to see if we currently have a multi sort or not. It applies
         * each sorter field/direction pair in turn by building an OR'ed master sorting function and running it against
         * the full dataset
         */
        sortData : function() {
            var sortInfo  = this.hasMultiSort ? this.multiSortInfo : this.sortInfo,
                direction = sortInfo.direction || "ASC",
                sorters   = sortInfo.sorters,
                sortFns   = [];

            //if we just have a single sorter, pretend it's the first in an array
            if (!this.hasMultiSort) {
                sorters = [{direction: direction, field: sortInfo.field}];
            }

            //create a sorter function for each sorter field/direction combo
            for (var i=0, j = sorters.length; i < j; i++) {
                sortFns.push(this.createSortFunction(sorters[i].field, sorters[i].direction));
            }

            if (sortFns.length == 0) {
                return;
            }

            //the direction modifier is multiplied with the result of the sorting functions to provide overall sort direction
            //(as opposed to direction per field)
            var directionModifier = direction.toUpperCase() == "DESC" ? -1 : 1;

            //create a function which ORs each sorter together to enable multi-sort
            var fn = function(r1, r2) {
              var result = sortFns[0].call(this, r1, r2);

              //if we have more than one sorter, OR any additional sorter functions together
              if (sortFns.length > 1) {
                  for (var i=1, j = sortFns.length; i < j; i++) {
                      result = result || sortFns[i].call(this, r1, r2);
                  }
              }

              return directionModifier * result;
            };

            //sort the data
            this.data.sort(direction, fn);
            if (this.snapshot && this.snapshot != this.data) {
                this.snapshot.sort(direction, fn);
            }
        },

        /**
         * @private
         * Creates and returns a function which sorts an array by the given field and direction
         * @param {String} field The field to create the sorter for
         * @param {String} direction The direction to sort by (defaults to "ASC")
         * @return {Function} A function which sorts by the field/direction combination provided
         */
        createSortFunction: function(field, direction) {
            direction = direction || "ASC";
            var directionModifier = direction.toUpperCase() == "DESC" ? -1 : 1;

            var sortType = this.fields.get(field).sortType;

            //create a comparison function. Takes 2 records, returns 1 if record 1 is greater,
            //-1 if record 2 is greater or 0 if they are equal
            return function(r1, r2) {
                var v1 = sortType(r1.data[field]),
                    v2 = sortType(r2.data[field]);

                return directionModifier * (v1 > v2 ? 1 : (v1 < v2 ? -1 : 0));
            };
        },

        /**
         * Sets the default sort column and order to be used by the next {@link #load} operation.
         * @param {String} fieldName The name of the field to sort by.
         * @param {String} dir (optional) The sort order, 'ASC' or 'DESC' (case-sensitive, defaults to <tt>'ASC'</tt>)
         */
        setDefaultSort : function(field, dir) {
            dir = dir ? dir.toUpperCase() : 'ASC';
            this.sortInfo = {field: field, direction: dir};
            this.sortToggle[field] = dir;
        },

        /**
         * Sort the Records.
         * If remote sorting is used, the sort is performed on the server, and the cache is reloaded. If local
         * sorting is used, the cache is sorted internally. See also {@link #remoteSort} and {@link #paramNames}.
         * This function accepts two call signatures - pass in a field name as the first argument to sort on a single
         * field, or pass in an array of sort configuration objects to sort by multiple fields.
         * Single sort example:
         * store.sort('name', 'ASC');
         * Multi sort example:
         * store.sort([
         *   {
         *     field    : 'name',
         *     direction: 'ASC'
         *   },
         *   {
         *     field    : 'salary',
         *     direction: 'DESC'
         *   }
         * ], 'ASC');
         * In this second form, the sort configs are applied in order, with later sorters sorting within earlier sorters' results.
         * For example, if two records with the same name are present they will also be sorted by salary if given the sort configs
         * above. Any number of sort configs can be added.
         * @param {String/Array} fieldName The name of the field to sort by, or an array of ordered sort configs
         * @param {String} dir (optional) The sort order, 'ASC' or 'DESC' (case-sensitive, defaults to <tt>'ASC'</tt>)
         */
        sort : function(fieldName, dir) {
            if (Ext.isArray(arguments[0])) {
                return this.multiSort.call(this, fieldName, dir);
            } else {
                return this.singleSort(fieldName, dir);
            }
        },

        /**
         * Sorts the store contents by a single field and direction. This is called internally by {@link sort} and would
         * not usually be called manually
         * @param {String} fieldName The name of the field to sort by.
         * @param {String} dir (optional) The sort order, 'ASC' or 'DESC' (case-sensitive, defaults to <tt>'ASC'</tt>)
         */
        singleSort: function(fieldName, dir) {
            var field = this.fields.get(fieldName);
            if (!field) {
                return false;
            }

            var name       = field.name,
                sortInfo   = this.sortInfo || null,
                sortToggle = this.sortToggle ? this.sortToggle[name] : null;

            if (!dir) {
                if (sortInfo && sortInfo.field == name) { // toggle sort dir
                    dir = (this.sortToggle[name] || 'ASC').toggle('ASC', 'DESC');
                } else {
                    dir = field.sortDir;
                }
            }

            this.sortToggle[name] = dir;
            this.sortInfo = {field: name, direction: dir};
            this.hasMultiSort = false;

            if (this.remoteSort) {
                if (!this.load(this.lastOptions)) {
                    if (sortToggle) {
                        this.sortToggle[name] = sortToggle;
                    }
                    if (sortInfo) {
                        this.sortInfo = sortInfo;
                    }
                }
            } else {
                this.applySort();
                this.fireEvent('datachanged', this);
            }
            return true;
        },

        /**
         * Sorts the contents of this store by multiple field/direction sorters. This is called internally by {@link sort}
         * and would not usually be called manually.
         * Multi sorting only currently applies to local datasets - multiple sort data is not currently sent to a proxy
         * if remoteSort is used.
         * @param {Array} sorters Array of sorter objects (field and direction)
         * @param {String} direction Overall direction to sort the ordered results by (defaults to "ASC")
         */
        multiSort: function(sorters, direction) {
            this.hasMultiSort = true;
            direction = direction || "ASC";

            //toggle sort direction
            if (this.multiSortInfo && direction == this.multiSortInfo.direction) {
                direction = direction.toggle("ASC", "DESC");
            }

            /**
             * Object containing overall sort direction and an ordered array of sorter configs used when sorting on multiple fields
             * @property multiSortInfo
             * @type Object
             */
            this.multiSortInfo = {
                sorters  : sorters,
                direction: direction
            };

            if (this.remoteSort) {
                this.singleSort(sorters[0].field, sorters[0].direction);

            } else {
                this.applySort();
                this.fireEvent('datachanged', this);
            }
        },

        /**
         * Calls the specified function for each of the {@link Ext.data.Record Records} in the cache.
         * @param {Function} fn The function to call. The {@link Ext.data.Record Record} is passed as the first parameter.
         * Returning <tt>false</tt> aborts and exits the iteration.
         * @param {Object} scope (optional) The scope (<code>this</code> reference) in which the function is executed.
         * Defaults to the current {@link Ext.data.Record Record} in the iteration.
         */
        each : function(fn, scope){
            this.data.each(fn, scope);
        },

        /**
         * Gets all {@link Ext.data.Record records} modified since the last commit.  Modified records are
         * persisted across load operations (e.g., during paging). <b>Note</b>: deleted records are not
         * included.  See also <tt>{@link #pruneModifiedRecords}</tt> and
         * {@link Ext.data.Record}<tt>{@link Ext.data.Record#markDirty markDirty}.</tt>.
         * @return {Ext.data.Record[]} An array of {@link Ext.data.Record Records} containing outstanding
         * modifications.  To obtain modified fields within a modified record see
         *{@link Ext.data.Record}<tt>{@link Ext.data.Record#modified modified}.</tt>.
         */
        getModifiedRecords : function(){
            return this.modified;
        },

        /**
         * Sums the value of <tt>property</tt> for each {@link Ext.data.Record record} between <tt>start</tt>
         * and <tt>end</tt> and returns the result.
         * @param {String} property A field in each record
         * @param {Number} start (optional) The record index to start at (defaults to <tt>0</tt>)
         * @param {Number} end (optional) The last record index to include (defaults to length - 1)
         * @return {Number} The sum
         */
        sum : function(property, start, end){
            var rs = this.data.items, v = 0;
            start = start || 0;
            end = (end || end === 0) ? end : rs.length-1;

            for(var i = start; i <= end; i++){
                v += (rs[i].data[property] || 0);
            }
            return v;
        },

        /**
         * @private
         * Returns a filter function used to test a the given property's value. Defers most of the work to
         * Ext.util.MixedCollection's createValueMatcher function
         * @param {String} property The property to create the filter function for
         * @param {String/RegExp} value The string/regex to compare the property value to
         * @param {Boolean} anyMatch True if we don't care if the filter value is not the full value (defaults to false)
         * @param {Boolean} caseSensitive True to create a case-sensitive regex (defaults to false)
         * @param {Boolean} exactMatch True to force exact match (^ and $ characters added to the regex). Defaults to false. Ignored if anyMatch is true.
         */
        createFilterFn : function(property, value, anyMatch, caseSensitive, exactMatch){
            if(Ext.isEmpty(value, false)){
                return false;
            }
            value = this.data.createValueMatcher(value, anyMatch, caseSensitive, exactMatch);
            return function(r) {
                return value.test(r.data[property]);
            };
        },

        /**
         * @private
         * Given an array of filter functions (each with optional scope), constructs and returns a single function that returns
         * the result of all of the filters ANDed together
         * @param {Array} filters The array of filter objects (each object should contain an 'fn' and optional scope)
         * @return {Function} The multiple filter function
         */
        createMultipleFilterFn: function(filters) {
            return function(record) {
                var isMatch = true;

                for (var i=0, j = filters.length; i < j; i++) {
                    var filter = filters[i],
                        fn     = filter.fn,
                        scope  = filter.scope;

                    isMatch = isMatch && fn.call(scope, record);
                }

                return isMatch;
            };
        },

        /**
         * Filter the {@link Ext.data.Record records} by a specified property. Alternatively, pass an array of filter
         * options to filter by more than one property.
         * Single filter example:
         * store.filter('name', 'Ed', true, true); //finds all records containing the substring 'Ed'
         * Multiple filter example:
         * <pre><code>
         * store.filter([
         *   {
         *     property     : 'name',
         *     value        : 'Ed',
         *     anyMatch     : true, //optional, defaults to true
         *     caseSensitive: true  //optional, defaults to true
         *   },
         *
         *   //filter functions can also be passed
         *   {
         *     fn   : function(record) {
         *       return record.get('age') == 24
         *     },
         *     scope: this
         *   }
         * ]);
         * </code></pre>
         * @param {String|Array} field A field on your records, or an array containing multiple filter options
         * @param {String/RegExp} value Either a string that the field should begin with, or a RegExp to test
         * against the field.
         * @param {Boolean} anyMatch (optional) <tt>true</tt> to match any part not just the beginning
         * @param {Boolean} caseSensitive (optional) <tt>true</tt> for case sensitive comparison
         * @param {Boolean} exactMatch (optional) True to force exact match (^ and $ characters added to the regex). Defaults to false. Ignored if anyMatch is true.
         */
        filter : function(property, value, anyMatch, caseSensitive, exactMatch){
            var fn;
            //we can accept an array of filter objects, or a single filter object - normalize them here
            if (Ext.isObject(property)) {
                property = [property];
            }

            if (Ext.isArray(property)) {
                var filters = [];

                //normalize the filters passed into an array of filter functions
                for (var i=0, j = property.length; i < j; i++) {
                    var filter = property[i],
                        func   = filter.fn,
                        scope  = filter.scope || this;

                    //if we weren't given a filter function, construct one now
                    if (!Ext.isFunction(func)) {
                        func = this.createFilterFn(filter.property, filter.value, filter.anyMatch, filter.caseSensitive, filter.exactMatch);
                    }

                    filters.push({fn: func, scope: scope});
                }

                fn = this.createMultipleFilterFn(filters);
            } else {
                //classic single property filter
                fn = this.createFilterFn(property, value, anyMatch, caseSensitive, exactMatch);
            }

            return fn ? this.filterBy(fn) : this.clearFilter();
        },

        /**
         * Filter by a function. The specified function will be called for each
         * Record in this Store. If the function returns <tt>true</tt> the Record is included,
         * otherwise it is filtered out.
         * @param {Function} fn The function to be called. It will be passed the following parameters:<ul>
         * <li><b>record</b> : Ext.data.Record<p class="sub-desc">The {@link Ext.data.Record record}
         * to test for filtering. Access field values using {@link Ext.data.Record#get}.</p></li>
         * <li><b>id</b> : Object<p class="sub-desc">The ID of the Record passed.</p></li>
         * </ul>
         * @param {Object} scope (optional) The scope (<code>this</code> reference) in which the function is executed. Defaults to this Store.
         */
        filterBy : function(fn, scope){
            this.snapshot = this.snapshot || this.data;
            this.data = this.queryBy(fn, scope || this);
            this.fireEvent('datachanged', this);
        },

        /**
         * Revert to a view of the Record cache with no filtering applied.
         * @param {Boolean} suppressEvent If <tt>true</tt> the filter is cleared silently without firing the
         * {@link #datachanged} event.
         */
        clearFilter : function(suppressEvent){
            if(this.isFiltered()){
                this.data = this.snapshot;
                delete this.snapshot;
                if(suppressEvent !== true){
                    this.fireEvent('datachanged', this);
                }
            }
        },

        /**
         * Returns true if this store is currently filtered
         * @return {Boolean}
         */
        isFiltered : function(){
            return !!this.snapshot && this.snapshot != this.data;
        },

        /**
         * Query the records by a specified property.
         * @param {String} field A field on your records
         * @param {String/RegExp} value Either a string that the field
         * should begin with, or a RegExp to test against the field.
         * @param {Boolean} anyMatch (optional) True to match any part not just the beginning
         * @param {Boolean} caseSensitive (optional) True for case sensitive comparison
         * @return {MixedCollection} Returns an Ext.util.MixedCollection of the matched records
         */
        query : function(property, value, anyMatch, caseSensitive){
            var fn = this.createFilterFn(property, value, anyMatch, caseSensitive);
            return fn ? this.queryBy(fn) : this.data.clone();
        },

        /**
         * Query the cached records in this Store using a filtering function. The specified function
         * will be called with each record in this Store. If the function returns <tt>true</tt> the record is
         * included in the results.
         * @param {Function} fn The function to be called. It will be passed the following parameters:<ul>
         * <li><b>record</b> : Ext.data.Record<p class="sub-desc">The {@link Ext.data.Record record}
         * to test for filtering. Access field values using {@link Ext.data.Record#get}.</p></li>
         * <li><b>id</b> : Object<p class="sub-desc">The ID of the Record passed.</p></li>
         * </ul>
         * @param {Object} scope (optional) The scope (<code>this</code> reference) in which the function is executed. Defaults to this Store.
         * @return {MixedCollection} Returns an Ext.util.MixedCollection of the matched records
         **/
        queryBy : function(fn, scope){
            var data = this.snapshot || this.data;
            return data.filterBy(fn, scope||this);
        },

        /**
         * Finds the index of the first matching Record in this store by a specific field value.
         * @param {String} fieldName The name of the Record field to test.
         * @param {String/RegExp} value Either a string that the field value
         * should begin with, or a RegExp to test against the field.
         * @param {Number} startIndex (optional) The index to start searching at
         * @param {Boolean} anyMatch (optional) True to match any part of the string, not just the beginning
         * @param {Boolean} caseSensitive (optional) True for case sensitive comparison
         * @return {Number} The matched index or -1
         */
        find : function(property, value, start, anyMatch, caseSensitive){
            var fn = this.createFilterFn(property, value, anyMatch, caseSensitive);
            return fn ? this.data.findIndexBy(fn, null, start) : -1;
        },

        /**
         * Finds the index of the first matching Record in this store by a specific field value.
         * @param {String} fieldName The name of the Record field to test.
         * @param {Mixed} value The value to match the field against.
         * @param {Number} startIndex (optional) The index to start searching at
         * @return {Number} The matched index or -1
         */
        findExact: function(property, value, start){
            return this.data.findIndexBy(function(rec){
                return rec.get(property) === value;
            }, this, start);
        },

        /**
         * Find the index of the first matching Record in this Store by a function.
         * If the function returns <tt>true</tt> it is considered a match.
         * @param {Function} fn The function to be called. It will be passed the following parameters:<ul>
         * <li><b>record</b> : Ext.data.Record<p class="sub-desc">The {@link Ext.data.Record record}
         * to test for filtering. Access field values using {@link Ext.data.Record#get}.</p></li>
         * <li><b>id</b> : Object<p class="sub-desc">The ID of the Record passed.</p></li>
         * </ul>
         * @param {Object} scope (optional) The scope (<code>this</code> reference) in which the function is executed. Defaults to this Store.
         * @param {Number} startIndex (optional) The index to start searching at
         * @return {Number} The matched index or -1
         */
        findBy : function(fn, scope, start){
            return this.data.findIndexBy(fn, scope, start);
        },

        /**
         * Collects unique values for a particular dataIndex from this store.
         * @param {String} dataIndex The property to collect
         * @param {Boolean} allowNull (optional) Pass true to allow null, undefined or empty string values
         * @param {Boolean} bypassFilter (optional) Pass true to collect from all records, even ones which are filtered
         * @return {Array} An array of the unique values
         **/
        collect : function(dataIndex, allowNull, bypassFilter){
            var d = (bypassFilter === true && this.snapshot) ?
                    this.snapshot.items : this.data.items;
            var v, sv, r = [], l = {};
            for(var i = 0, len = d.length; i < len; i++){
                v = d[i].data[dataIndex];
                sv = String(v);
                if((allowNull || !Ext.isEmpty(v)) && !l[sv]){
                    l[sv] = true;
                    r[r.length] = v;
                }
            }
            return r;
        },

        // private
        afterEdit : function(record){
            if(this.modified.indexOf(record) == -1){
                this.modified.push(record);
            }
            this.fireEvent('update', this, record, Ext.data.Record.EDIT);
        },

        // private
        afterReject : function(record){
            this.modified.remove(record);
            this.fireEvent('update', this, record, Ext.data.Record.REJECT);
        },

        // private
        afterCommit : function(record){
            this.modified.remove(record);
            this.fireEvent('update', this, record, Ext.data.Record.COMMIT);
        },

        /**
         * Commit all Records with {@link #getModifiedRecords outstanding changes}. To handle updates for changes,
         * subscribe to the Store's {@link #update update event}, and perform updating when the third parameter is
         * Ext.data.Record.COMMIT.
         */
        commitChanges : function(){
            var modified = this.modified.slice(0),
                length   = modified.length,
                i;

            for (i = 0; i < length; i++){
                modified[i].commit();
            }

            this.modified = [];
            this.removed  = [];
        },

        /**
         * {@link Ext.data.Record#reject Reject} outstanding changes on all {@link #getModifiedRecords modified records}.
         */
        rejectChanges : function() {
            var modified = this.modified.slice(0),
                removed  = this.removed.slice(0).reverse(),
                mLength  = modified.length,
                rLength  = removed.length,
                i;

            for (i = 0; i < mLength; i++) {
                modified[i].reject();
            }

            for (i = 0; i < rLength; i++) {
                this.insert(removed[i].lastIndex || 0, removed[i]);
                removed[i].reject();
            }

            this.modified = [];
            this.removed  = [];
        },

        // private
        onMetaChange : function(meta){
            this.recordType = this.reader.recordType;
            this.fields = this.recordType.prototype.fields;
            delete this.snapshot;
            if(this.reader.meta.sortInfo){
                this.sortInfo = this.reader.meta.sortInfo;
            }else if(this.sortInfo  && !this.fields.get(this.sortInfo.field)){
                delete this.sortInfo;
            }
            if(this.writer){
                this.writer.meta = this.reader.meta;
            }
            this.modified = [];
            this.fireEvent('metachange', this, this.reader.meta);
        },

        // private
        findInsertIndex : function(record){
            this.suspendEvents();
            var data = this.data.clone();
            this.data.add(record);
            this.applySort();
            var index = this.data.indexOf(record);
            this.data = data;
            this.resumeEvents();
            return index;
        },

        /**
         * Set the value for a property name in this store's {@link #baseParams}.  Usage:</p><pre><code>
    myStore.setBaseParam('foo', {bar:3});
    </code></pre>
         * @param {String} name Name of the property to assign
         * @param {Mixed} value Value to assign the <tt>name</tt>d property
         **/
        setBaseParam : function (name, value){
            this.baseParams = this.baseParams || {};
            this.baseParams[name] = value;
        }
    });

    Ext.reg('store', Ext.data.Store);

    /**
     * @class Ext.data.Store.Error
     * @extends Ext.Error
     * Store Error extension.
     * @param {String} name
     */
    Ext.data.Store.Error = Ext.extend(Ext.Error, {
        name: 'Ext.data.Store'
    });
    Ext.apply(Ext.data.Store.Error.prototype, {
        lang: {
            'writer-undefined' : 'Attempted to execute a write-action without a DataWriter installed.'
        }
    });