    /**
     * @author Ed Spencer
     * @class Ext.data.Store
     * @extends Ext.data.AbstractStore
     *
     * <p>The Store class encapsulates a client side cache of {@link Ext.data.Model Model} objects. Stores load
     * data via a {@link Ext.data.proxy.Proxy Proxy}, and also provide functions for {@link #sort sorting},
     * {@link #filter filtering} and querying the {@link Ext.data.Model model} instances contained within it.</p>
     *
     * <p>Creating a Store is easy - we just tell it the Model and the Proxy to use to load and save its data:</p>
     *
    <pre><code>
    // Set up a {@link Ext.data.Model model} to use in our Store
    Ext.define('User', {
        extend: 'Ext.data.Model',
        fields: [
            {name: 'firstName', type: 'string'},
            {name: 'lastName',  type: 'string'},
            {name: 'age',       type: 'int'},
            {name: 'eyeColor',  type: 'string'}
        ]
    });

    var myStore = new Ext.data.Store({
        model: 'User',
        proxy: {
            type: 'ajax',
            url : '/users.json',
            reader: {
                type: 'json',
                root: 'users'
            }
        },
        autoLoad: true
    });
    </code></pre>

     * <p>In the example above we configured an AJAX proxy to load data from the url '/users.json'. We told our Proxy
     * to use a {@link Ext.data.reader.Json JsonReader} to parse the response from the server into Model object -
     * {@link Ext.data.reader.Json see the docs on JsonReader} for details.</p>
     *
     * <p><u>Inline data</u></p>
     *
     * <p>Stores can also load data inline. Internally, Store converts each of the objects we pass in as {@link #data}
     * into Model instances:</p>
     *
    <pre><code>
    new Ext.data.Store({
        model: 'User',
        data : [
            {firstName: 'Ed',    lastName: 'Spencer'},
            {firstName: 'Tommy', lastName: 'Maintz'},
            {firstName: 'Aaron', lastName: 'Conran'},
            {firstName: 'Jamie', lastName: 'Avins'}
        ]
    });
    </code></pre>
     *
     * <p>Loading inline data using the method above is great if the data is in the correct format already (e.g. it doesn't need
     * to be processed by a {@link Ext.data.reader.Reader reader}). If your inline data requires processing to decode the data structure,
     * use a {@link Ext.data.proxy.Memory MemoryProxy} instead (see the {@link Ext.data.proxy.Memory MemoryProxy} docs for an example).</p>
     *
     * <p>Additional data can also be loaded locally using {@link #add}.</p>
     *
     * <p><u>Loading Nested Data</u></p>
     *
     * <p>Applications often need to load sets of associated data - for example a CRM system might load a User and her Orders.
     * Instead of issuing an AJAX request for the User and a series of additional AJAX requests for each Order, we can load a nested dataset
     * and allow the Reader to automatically populate the associated models. Below is a brief example, see the {@link Ext.data.reader.Reader} intro
     * docs for a full explanation:</p>
     *
    <pre><code>
    var store = new Ext.data.Store({
        autoLoad: true,
        model: "User",
        proxy: {
            type: 'ajax',
            url : 'users.json',
            reader: {
                type: 'json',
                root: 'users'
            }
        }
    });
    </code></pre>
     *
     * <p>Which would consume a response like this:</p>
     *
    <pre><code>
    {
        "users": [
            {
                "id": 1,
                "name": "Ed",
                "orders": [
                    {
                        "id": 10,
                        "total": 10.76,
                        "status": "invoiced"
                    },
                    {
                        "id": 11,
                        "total": 13.45,
                        "status": "shipped"
                    }
                ]
            }
        ]
    }
    </code></pre>
     *
     * <p>See the {@link Ext.data.reader.Reader} intro docs for a full explanation.</p>
     *
     * <p><u>Filtering and Sorting</u></p>
     *
     * <p>Stores can be sorted and filtered - in both cases either remotely or locally. The {@link #sorters} and {@link #filters} are
     * held inside {@link Ext.util.MixedCollection MixedCollection} instances to make them easy to manage. Usually it is sufficient to
     * either just specify sorters and filters in the Store configuration or call {@link #sort} or {@link #filter}:
     *
    <pre><code>
    var store = new Ext.data.Store({
        model: 'User',
        sorters: [
            {
                property : 'age',
                direction: 'DESC'
            },
            {
                property : 'firstName',
                direction: 'ASC'
            }
        ],

        filters: [
            {
                property: 'firstName',
                value   : /Ed/
            }
        ]
    });
    </code></pre>
     *
     * <p>The new Store will keep the configured sorters and filters in the MixedCollection instances mentioned above. By default, sorting
     * and filtering are both performed locally by the Store - see {@link #remoteSort} and {@link #remoteFilter} to allow the server to
     * perform these operations instead.</p>
     *
     * <p>Filtering and sorting after the Store has been instantiated is also easy. Calling {@link #filter} adds another filter to the Store
     * and automatically filters the dataset (calling {@link #filter} with no arguments simply re-applies all existing filters). Note that by
     * default {@link #sortOnFilter} is set to true, which means that your sorters are automatically reapplied if using local sorting.</p>
     *
    <pre><code>
    store.filter('eyeColor', 'Brown');
    </code></pre>
     *
     * <p>Change the sorting at any time by calling {@link #sort}:</p>
     *
    <pre><code>
    store.sort('height', 'ASC');
    </code></pre>
     *
     * <p>Note that all existing sorters will be removed in favor of the new sorter data (if {@link #sort} is called with no arguments,
     * the existing sorters are just reapplied instead of being removed). To keep existing sorters and add new ones, just add them
     * to the MixedCollection:</p>
     *
    <pre><code>
    store.sorters.add(new Ext.util.Sorter({
        property : 'shoeSize',
        direction: 'ASC'
    }));

    store.sort();
    </code></pre>
     *
     * <p><u>Registering with StoreManager</u></p>
     *
     * <p>Any Store that is instantiated with a {@link #storeId} will automatically be registed with the {@link Ext.data.StoreManager StoreManager}.
     * This makes it easy to reuse the same store in multiple views:</p>
     *
     <pre><code>
    //this store can be used several times
    new Ext.data.Store({
        model: 'User',
        storeId: 'usersStore'
    });

    new Ext.List({
        store: 'usersStore',

        //other config goes here
    });

    new Ext.view.View({
        store: 'usersStore',

        //other config goes here
    });
    </code></pre>
     *
     * <p><u>Further Reading</u></p>
     *
     * <p>Stores are backed up by an ecosystem of classes that enables their operation. To gain a full understanding of these
     * pieces and how they fit together, see:</p>
     *
     * <ul style="list-style-type: disc; padding-left: 25px">
     * <li>{@link Ext.data.proxy.Proxy Proxy} - overview of what Proxies are and how they are used</li>
     * <li>{@link Ext.data.Model Model} - the core class in the data package</li>
     * <li>{@link Ext.data.reader.Reader Reader} - used by any subclass of {@link Ext.data.proxy.Server ServerProxy} to read a response</li>
     * </ul>
     *
     */
    Ext.define('Ext.data.Store', {
        extend: 'Ext.data.AbstractStore',

        alias: 'store.store',

        requires: ['Ext.ModelManager', 'Ext.data.Model', 'Ext.util.Grouper'],
        uses: ['Ext.data.proxy.Memory'],

        /**
         * @cfg {Boolean} remoteSort
         * True to defer any sorting operation to the server. If false, sorting is done locally on the client. Defaults to <tt>false</tt>.
         */
        remoteSort: false,

        /**
         * @cfg {Boolean} remoteFilter
         * True to defer any filtering operation to the server. If false, filtering is done locally on the client. Defaults to <tt>false</tt>.
         */
        remoteFilter: false,

        /**
         * @cfg {Boolean} remoteGroup
         * True if the grouping should apply on the server side, false if it is local only (defaults to false).  If the
         * grouping is local, it can be applied immediately to the data.  If it is remote, then it will simply act as a
         * helper, automatically sending the grouping information to the server.
         */
        remoteGroup : false,

        /**
         * @cfg {String/Ext.data.proxy.Proxy/Object} proxy The Proxy to use for this Store. This can be either a string, a config
         * object or a Proxy instance - see {@link #setProxy} for details.
         */

        /**
         * @cfg {Array} data Optional array of Model instances or data objects to load locally. See "Inline data" above for details.
         */

        /**
         * @cfg {String} model The {@link Ext.data.Model} associated with this store
         */

        /**
         * The (optional) field by which to group data in the store. Internally, grouping is very similar to sorting - the
         * groupField and {@link #groupDir} are injected as the first sorter (see {@link #sort}). Stores support a single
         * level of grouping, and groups can be fetched via the {@link #getGroups} method.
         * @property groupField
         * @type String
         */
        groupField: undefined,

        /**
         * The direction in which sorting should be applied when grouping. Defaults to "ASC" - the other supported value is "DESC"
         * @property groupDir
         * @type String
         */
        groupDir: "ASC",

        /**
         * @cfg {Number} pageSize
         * The number of records considered to form a 'page'. This is used to power the built-in
         * paging using the nextPage and previousPage functions. Defaults to 25.
         */
        pageSize: 25,

        /**
         * The page that the Store has most recently loaded (see {@link #loadPage})
         * @property currentPage
         * @type Number
         */
        currentPage: 1,

        /**
         * @cfg {Boolean} clearOnPageLoad True to empty the store when loading another page via {@link #loadPage},
         * {@link #nextPage} or {@link #previousPage} (defaults to true). Setting to false keeps existing records, allowing
         * large data sets to be loaded one page at a time but rendered all together.
         */
        clearOnPageLoad: true,

        /**
         * True if the Store is currently loading via its Proxy
         * @property loading
         * @type Boolean
         * @private
         */
        loading: false,

        /**
         * @cfg {Boolean} sortOnFilter For local filtering only, causes {@link #sort} to be called whenever {@link #filter} is called,
         * causing the sorters to be reapplied after filtering. Defaults to true
         */
        sortOnFilter: true,

        /**
         * @cfg {Boolean} buffered
         * Allow the store to buffer and pre-fetch pages of records. This is to be used in conjunction with a view will
         * tell the store to pre-fetch records ahead of a time.
         */
        buffered: false,

        /**
         * @cfg {Number} purgePageCount
         * The number of pages to keep in the cache before purging additional records. A value of 0 indicates to never purge the prefetched data.
         * This option is only relevant when the {@link #buffered} option is set to true.
         */
        purgePageCount: 5,

        isStore: true,

        /**
         * Creates the store.
         * @param {Object} config (optional) Config object
         */
        constructor: function(config) {
            config = config || {};

            var me = this,
                groupers = config.groupers || me.groupers,
                groupField = config.groupField || me.groupField,
                proxy,
                data;

            if (config.buffered || me.buffered) {
                me.prefetchData = Ext.create('Ext.util.MixedCollection', false, function(record) {
                    return record.index;
                });
                me.pendingRequests = [];
                me.pagesRequested = [];

                me.sortOnLoad = false;
                me.filterOnLoad = false;
            }

            me.addEvents(
                /**
                 * @event beforeprefetch
                 * Fires before a prefetch occurs. Return false to cancel.
                 * @param {Ext.data.store} this
                 * @param {Ext.data.Operation} operation The associated operation
                 */
                'beforeprefetch',
                /**
                 * @event groupchange
                 * Fired whenever the grouping in the grid changes
                 * @param {Ext.data.Store} store The store
                 * @param {Array} groupers The array of grouper objects
                 */
                'groupchange',
                /**
                 * @event load
                 * Fires whenever records have been prefetched
                 * @param {Ext.data.store} this
                 * @param {Array} records An array of records
                 * @param {Boolean} successful True if the operation was successful.
                 * @param {Ext.data.Operation} operation The associated operation
                 */
                'prefetch'
            );
            data = config.data || me.data;

            /**
             * The MixedCollection that holds this store's local cache of records
             * @property data
             * @type Ext.util.MixedCollection
             */
            me.data = Ext.create('Ext.util.MixedCollection', false, function(record) {
                return record.internalId;
            });

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

            if (!groupers && groupField) {
                groupers = [{
                    property : groupField,
                    direction: config.groupDir || me.groupDir
                }];
            }
            delete config.groupers;

            /**
             * The collection of {@link Ext.util.Grouper Groupers} currently applied to this Store
             * @property groupers
             * @type Ext.util.MixedCollection
             */
            me.groupers = Ext.create('Ext.util.MixedCollection');
            me.groupers.addAll(me.decodeGroupers(groupers));

            this.callParent([config]);
            // don't use *config* anymore from here on... use *me* instead...

            if (me.groupers.items.length) {
                me.sort(me.groupers.items, 'prepend', false);
            }

            proxy = me.proxy;
            data = me.inlineData;

            if (data) {
                if (proxy instanceof Ext.data.proxy.Memory) {
                    proxy.data = data;
                    me.read();
                } else {
                    me.add.apply(me, data);
                }

                me.sort();
                delete me.inlineData;
            } else if (me.autoLoad) {
                Ext.defer(me.load, 10, me, [typeof me.autoLoad === 'object' ? me.autoLoad: undefined]);
                // Remove the defer call, we may need reinstate this at some point, but currently it's not obvious why it's here.
                // this.load(typeof this.autoLoad == 'object' ? this.autoLoad : undefined);
            }
        },

        onBeforeSort: function() {
            this.sort(this.groupers.items, 'prepend', false);
        },

        /**
         * @private
         * Normalizes an array of grouper objects, ensuring that they are all Ext.util.Grouper instances
         * @param {Array} groupers The groupers array
         * @return {Array} Array of Ext.util.Grouper objects
         */
        decodeGroupers: function(groupers) {
            if (!Ext.isArray(groupers)) {
                if (groupers === undefined) {
                    groupers = [];
                } else {
                    groupers = [groupers];
                }
            }

            var length  = groupers.length,
                Grouper = Ext.util.Grouper,
                config, i;

            for (i = 0; i < length; i++) {
                config = groupers[i];

                if (!(config instanceof Grouper)) {
                    if (Ext.isString(config)) {
                        config = {
                            property: config
                        };
                    }

                    Ext.applyIf(config, {
                        root     : 'data',
                        direction: "ASC"
                    });

                    //support for 3.x style sorters where a function can be defined as 'fn'
                    if (config.fn) {
                        config.sorterFn = config.fn;
                    }

                    //support a function to be passed as a sorter definition
                    if (typeof config == 'function') {
                        config = {
                            sorterFn: config
                        };
                    }

                    groupers[i] = new Grouper(config);
                }
            }

            return groupers;
        },

        /**
         * Group data in the store
         * @param {String|Array} groupers Either a string name of one of the fields in this Store's configured {@link Ext.data.Model Model},
         * or an Array of grouper configurations.
         * @param {String} direction The overall direction to group the data by. Defaults to "ASC".
         */
        group: function(groupers, direction) {
            var me = this,
                grouper,
                newGroupers;

            if (Ext.isArray(groupers)) {
                newGroupers = groupers;
            } else if (Ext.isObject(groupers)) {
                newGroupers = [groupers];
            } else if (Ext.isString(groupers)) {
                grouper = me.groupers.get(groupers);

                if (!grouper) {
                    grouper = {
                        property : groupers,
                        direction: direction
                    };
                    newGroupers = [grouper];
                } else if (direction === undefined) {
                    grouper.toggle();
                } else {
                    grouper.setDirection(direction);
                }
            }

            if (newGroupers && newGroupers.length) {
                newGroupers = me.decodeGroupers(newGroupers);
                me.groupers.clear();
                me.groupers.addAll(newGroupers);
            }

            if (me.remoteGroup) {
                me.load({
                    scope: me,
                    callback: me.fireGroupChange
                });
            } else {
                me.sort();
                me.fireEvent('groupchange', me, me.groupers);
            }
        },

        /**
         * Clear any groupers in the store
         */
        clearGrouping: function(){
            var me = this;
            // Clear any groupers we pushed on to the sorters
            me.groupers.each(function(grouper){
                me.sorters.remove(grouper);
            });
            me.groupers.clear();
            if (me.remoteGroup) {
                me.load({
                    scope: me,
                    callback: me.fireGroupChange
                });
            } else {
                me.sort();
                me.fireEvent('groupchange', me, me.groupers);
            }
        },

        /**
         * Checks if the store is currently grouped
         * @return {Boolean} True if the store is grouped.
         */
        isGrouped: function() {
            return this.groupers.getCount() > 0;
        },

        /**
         * Fires the groupchange event. Abstracted out so we can use it
         * as a callback
         * @private
         */
        fireGroupChange: function(){
            this.fireEvent('groupchange', this, this.groupers);
        },

        /**
         * Returns an object containing the result of applying grouping to the records in this store. See {@link #groupField},
         * {@link #groupDir} and {@link #getGroupString}. Example for a store containing records with a color field:
    <pre><code>
    var myStore = new Ext.data.Store({
        groupField: 'color',
        groupDir  : 'DESC'
    });

    myStore.getGroups(); //returns:
    [
        {
            name: 'yellow',
            children: [
                //all records where the color field is 'yellow'
            ]
        },
        {
            name: 'red',
            children: [
                //all records where the color field is 'red'
            ]
        }
    ]
    </code></pre>
         * @param {String} groupName (Optional) Pass in an optional groupName argument to access a specific group as defined by {@link #getGroupString}
         * @return {Array} The grouped data
         */
        getGroups: function(requestGroupString) {
            var records = this.data.items,
                length = records.length,
                groups = [],
                pointers = {},
                record,
                groupStr,
                group,
                i;

            for (i = 0; i < length; i++) {
                record = records[i];
                groupStr = this.getGroupString(record);
                group = pointers[groupStr];

                if (group === undefined) {
                    group = {
                        name: groupStr,
                        children: []
                    };

                    groups.push(group);
                    pointers[groupStr] = group;
                }

                group.children.push(record);
            }

            return requestGroupString ? pointers[requestGroupString] : groups;
        },

        /**
         * @private
         * For a given set of records and a Grouper, returns an array of arrays - each of which is the set of records
         * matching a certain group.
         */
        getGroupsForGrouper: function(records, grouper) {
            var length = records.length,
                groups = [],
                oldValue,
                newValue,
                record,
                group,
                i;

            for (i = 0; i < length; i++) {
                record = records[i];
                newValue = grouper.getGroupString(record);

                if (newValue !== oldValue) {
                    group = {
                        name: newValue,
                        grouper: grouper,
                        records: []
                    };
                    groups.push(group);
                }

                group.records.push(record);

                oldValue = newValue;
            }

            return groups;
        },

        /**
         * @private
         * This is used recursively to gather the records into the configured Groupers. The data MUST have been sorted for
         * this to work properly (see {@link #getGroupData} and {@link #getGroupsForGrouper}) Most of the work is done by
         * {@link #getGroupsForGrouper} - this function largely just handles the recursion.
         * @param {Array} records The set or subset of records to group
         * @param {Number} grouperIndex The grouper index to retrieve
         * @return {Array} The grouped records
         */
        getGroupsForGrouperIndex: function(records, grouperIndex) {
            var me = this,
                groupers = me.groupers,
                grouper = groupers.getAt(grouperIndex),
                groups = me.getGroupsForGrouper(records, grouper),
                length = groups.length,
                i;

            if (grouperIndex + 1 < groupers.length) {
                for (i = 0; i < length; i++) {
                    groups[i].children = me.getGroupsForGrouperIndex(groups[i].records, grouperIndex + 1);
                }
            }

            for (i = 0; i < length; i++) {
                groups[i].depth = grouperIndex;
            }

            return groups;
        },

        /**
         * @private
         * <p>Returns records grouped by the configured {@link #groupers grouper} configuration. Sample return value (in
         * this case grouping by genre and then author in a fictional books dataset):</p>
    <pre><code>
    [
        {
            name: 'Fantasy',
            depth: 0,
            records: [
                //book1, book2, book3, book4
            ],
            children: [
                {
                    name: 'Rowling',
                    depth: 1,
                    records: [
                        //book1, book2
                    ]
                },
                {
                    name: 'Tolkein',
                    depth: 1,
                    records: [
                        //book3, book4
                    ]
                }
            ]
        }
    ]
    </code></pre>
         * @param {Boolean} sort True to call {@link #sort} before finding groups. Sorting is required to make grouping
         * function correctly so this should only be set to false if the Store is known to already be sorted correctly
         * (defaults to true)
         * @return {Array} The group data
         */
        getGroupData: function(sort) {
            var me = this;
            if (sort !== false) {
                me.sort();
            }

            return me.getGroupsForGrouperIndex(me.data.items, 0);
        },

        /**
         * <p>Returns the string to group on for a given model instance. The default implementation of this method returns
         * the model's {@link #groupField}, but this can be overridden to group by an arbitrary string. For example, to
         * group by the first letter of a model's 'name' field, use the following code:</p>
    <pre><code>
    new Ext.data.Store({
        groupDir: 'ASC',
        getGroupString: function(instance) {
            return instance.get('name')[0];
        }
    });
    </code></pre>
         * @param {Ext.data.Model} instance The model instance
         * @return {String} The string to compare when forming groups
         */
        getGroupString: function(instance) {
            var group = this.groupers.first();
            if (group) {
                return instance.get(group.property);
            }
            return '';
        },
        /**
         * Inserts Model instances into the Store at the given index and fires the {@link #add} event.
         * See also <code>{@link #add}</code>.
         * @param {Number} index The start index at which to insert the passed Records.
         * @param {Ext.data.Model[]} records An Array of Ext.data.Model objects to add to the cache.
         */
        insert: function(index, records) {
            var me = this,
                sync = false,
                i,
                record,
                len;

            records = [].concat(records);
            for (i = 0, len = records.length; i < len; i++) {
                record = me.createModel(records[i]);
                record.set(me.modelDefaults);
                // reassign the model in the array in case it wasn't created yet
                records[i] = record;

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

                sync = sync || record.phantom === true;
            }

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

            me.fireEvent('add', me, records, index);
            me.fireEvent('datachanged', me);
            if (me.autoSync && sync) {
                me.sync();
            }
        },

        /**
         * Adds Model instances to the Store by instantiating them based on a JavaScript object. When adding already-
         * instantiated Models, use {@link #insert} instead. The instances will be added at the end of the existing collection.
         * This method accepts either a single argument array of Model instances or any number of model instance arguments.
         * Sample usage:
         *
    <pre><code>
    myStore.add({some: 'data'}, {some: 'other data'});
    </code></pre>
         *
         * @param {Object} data The data for each model
         * @return {Array} The array of newly created model instances
         */
        add: function(records) {
            //accept both a single-argument array of records, or any number of record arguments
            if (!Ext.isArray(records)) {
                records = Array.prototype.slice.apply(arguments);
            }

            var me = this,
                i = 0,
                length = records.length,
                record;

            for (; i < length; i++) {
                record = me.createModel(records[i]);
                // reassign the model in the array in case it wasn't created yet
                records[i] = record;
            }

            me.insert(me.data.length, records);

            return records;
        },

        /**
         * Converts a literal to a model, if it's not a model already
         * @private
         * @param record {Ext.data.Model/Object} The record to create
         * @return {Ext.data.Model}
         */
        createModel: function(record) {
            if (!record.isModel) {
                record = Ext.ModelManager.create(record, this.model);
            }

            return record;
        },

        /**
         * Calls the specified function for each of the {@link Ext.data.Model Records} in the cache.
         * @param {Function} fn The function to call. The {@link Ext.data.Model 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.Model Record} in the iteration.
         */
        each: function(fn, scope) {
            this.data.each(fn, scope);
        },

        /**
         * Removes the given record from the Store, firing the 'remove' event for each instance that is removed, plus a single
         * 'datachanged' event after removal.
         * @param {Ext.data.Model/Array} records The Ext.data.Model instance or array of instances to remove
         */
        remove: function(records, /* private */ isMove) {
            if (!Ext.isArray(records)) {
                records = [records];
            }

            /*
             * Pass the isMove parameter if we know we're going to be re-inserting this record
             */
            isMove = isMove === true;
            var me = this,
                sync = false,
                i = 0,
                length = records.length,
                isPhantom,
                index,
                record;

            for (; i < length; i++) {
                record = records[i];
                index = me.data.indexOf(record);

                if (me.snapshot) {
                    me.snapshot.remove(record);
                }

                if (index > -1) {
                    isPhantom = record.phantom === true;
                    if (!isMove && !isPhantom) {
                        // don't push phantom records onto removed
                        me.removed.push(record);
                    }

                    record.unjoin(me);
                    me.data.remove(record);
                    sync = sync || !isPhantom;

                    me.fireEvent('remove', me, record, index);
                }
            }

            me.fireEvent('datachanged', me);
            if (!isMove && me.autoSync && sync) {
                me.sync();
            }
        },

        /**
         * Removes the model instance at the given index
         * @param {Number} index The record index
         */
        removeAt: function(index) {
            var record = this.getAt(index);

            if (record) {
                this.remove(record);
            }
        },

        /**
         * <p>Loads data into the Store via the configured {@link #proxy}. This uses the Proxy to make an
         * asynchronous call to whatever storage backend the Proxy uses, automatically adding the retrieved
         * instances into the Store and calling an optional callback if required. Example usage:</p>
         *
    <pre><code>
    store.load({
        scope   : this,
        callback: function(records, operation, success) {
            //the {@link Ext.data.Operation operation} object contains all of the details of the load operation
            console.log(records);
        }
    });
    </code></pre>
         *
         * <p>If the callback scope does not need to be set, a function can simply be passed:</p>
         *
    <pre><code>
    store.load(function(records, operation, success) {
        console.log('loaded records');
    });
    </code></pre>
         *
         * @param {Object/Function} options Optional config object, passed into the Ext.data.Operation object before loading.
         */
        load: function(options) {
            var me = this;

            options = options || {};

            if (Ext.isFunction(options)) {
                options = {
                    callback: options
                };
            }

            Ext.applyIf(options, {
                groupers: me.groupers.items,
                page: me.currentPage,
                start: (me.currentPage - 1) * me.pageSize,
                limit: me.pageSize,
                addRecords: false
            });

            return me.callParent([options]);
        },

        /**
         * @private
         * Called internally when a Proxy has completed a load request
         */
        onProxyLoad: function(operation) {
            var me = this,
                resultSet = operation.getResultSet(),
                records = operation.getRecords(),
                successful = operation.wasSuccessful();

            if (resultSet) {
                me.totalCount = resultSet.total;
            }

            if (successful) {
                me.loadRecords(records, operation);
            }

            me.loading = false;
            me.fireEvent('load', me, records, successful);

            //TODO: deprecate this event, it should always have been 'load' instead. 'load' is now documented, 'read' is not.
            //People are definitely using this so can't deprecate safely until 2.x
            me.fireEvent('read', me, records, operation.wasSuccessful());

            //this is a callback that would have been passed to the 'read' function and is optional
            Ext.callback(operation.callback, operation.scope || me, [records, operation, successful]);
        },

        /**
         * Create any new records when a write is returned from the server.
         * @private
         * @param {Array} records The array of new records
         * @param {Ext.data.Operation} operation The operation that just completed
         * @param {Boolean} success True if the operation was successful
         */
        onCreateRecords: function(records, operation, success) {
            if (success) {
                var i = 0,
                    data = this.data,
                    snapshot = this.snapshot,
                    length = records.length,
                    originalRecords = operation.records,
                    record,
                    original,
                    index;

                /*
                 * Loop over each record returned from the server. Assume they are
                 * returned in order of how they were sent. If we find a matching
                 * record, replace it with the newly created one.
                 */
                for (; i < length; ++i) {
                    record = records[i];
                    original = originalRecords[i];
                    if (original) {
                        index = data.indexOf(original);
                        if (index > -1) {
                            data.removeAt(index);
                            data.insert(index, record);
                        }
                        if (snapshot) {
                            index = snapshot.indexOf(original);
                            if (index > -1) {
                                snapshot.removeAt(index);
                                snapshot.insert(index, record);
                            }
                        }
                        record.phantom = false;
                        record.join(this);
                    }
                }
            }
        },

        /**
         * Update any records when a write is returned from the server.
         * @private
         * @param {Array} records The array of updated records
         * @param {Ext.data.Operation} operation The operation that just completed
         * @param {Boolean} success True if the operation was successful
         */
        onUpdateRecords: function(records, operation, success){
            if (success) {
                var i = 0,
                    length = records.length,
                    data = this.data,
                    snapshot = this.snapshot,
                    record;

                for (; i < length; ++i) {
                    record = records[i];
                    data.replace(record);
                    if (snapshot) {
                        snapshot.replace(record);
                    }
                    record.join(this);
                }
            }
        },

        /**
         * Remove any records when a write is returned from the server.
         * @private
         * @param {Array} records The array of removed records
         * @param {Ext.data.Operation} operation The operation that just completed
         * @param {Boolean} success True if the operation was successful
         */
        onDestroyRecords: function(records, operation, success){
            if (success) {
                var me = this,
                    i = 0,
                    length = records.length,
                    data = me.data,
                    snapshot = me.snapshot,
                    record;

                for (; i < length; ++i) {
                    record = records[i];
                    record.unjoin(me);
                    data.remove(record);
                    if (snapshot) {
                        snapshot.remove(record);
                    }
                }
                me.removed = [];
            }
        },

        //inherit docs
        getNewRecords: function() {
            return this.data.filterBy(this.filterNew).items;
        },

        //inherit docs
        getUpdatedRecords: function() {
            return this.data.filterBy(this.filterUpdated).items;
        },

        /**
         * Filters the loaded set of records by a given set of filters.
         * @param {Mixed} filters The set of filters to apply to the data. These are stored internally on the store,
         * but the filtering itself is done on the Store's {@link Ext.util.MixedCollection MixedCollection}. See
         * MixedCollection's {@link Ext.util.MixedCollection#filter filter} method for filter syntax. Alternatively,
         * pass in a property string
         * @param {String} value Optional value to filter by (only if using a property string as the first argument)
         */
        filter: function(filters, value) {
            if (Ext.isString(filters)) {
                filters = {
                    property: filters,
                    value: value
                };
            }

            var me = this,
                decoded = me.decodeFilters(filters),
                i = 0,
                doLocalSort = me.sortOnFilter && !me.remoteSort,
                length = decoded.length;

            for (; i < length; i++) {
                me.filters.replace(decoded[i]);
            }

            if (me.remoteFilter) {
                //the load function will pick up the new filters and request the filtered data from the proxy
                me.load();
            } else {
                /**
                 * A pristine (unfiltered) collection of the records in this store. This is used to reinstate
                 * records when a filter is removed or changed
                 * @property snapshot
                 * @type Ext.util.MixedCollection
                 */
                if (me.filters.getCount()) {
                    me.snapshot = me.snapshot || me.data.clone();
                    me.data = me.data.filter(me.filters.items);

                    if (doLocalSort) {
                        me.sort();
                    }
                    // fire datachanged event if it hasn't already been fired by doSort
                    if (!doLocalSort || me.sorters.length < 1) {
                        me.fireEvent('datachanged', me);
                    }
                }
            }
        },

        /**
         * 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) {
            var me = this;

            me.filters.clear();

            if (me.remoteFilter) {
                me.load();
            } else if (me.isFiltered()) {
                me.data = me.snapshot.clone();
                delete me.snapshot;

                if (suppressEvent !== true) {
                    me.fireEvent('datachanged', me);
                }
            }
        },

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

        /**
         * 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.Model<p class="sub-desc">The {@link Ext.data.Model record}
         * to test for filtering. Access field values using {@link Ext.data.Model#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) {
            var me = this;

            me.snapshot = me.snapshot || me.data.clone();
            me.data = me.queryBy(fn, scope || me);
            me.fireEvent('datachanged', me);
        },

        /**
         * 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.Model<p class="sub-desc">The {@link Ext.data.Model record}
         * to test for filtering. Access field values using {@link Ext.data.Model#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 me = this,
            data = me.snapshot || me.data;
            return data.filterBy(fn, scope || me);
        },

        /**
         * Loads an array of data straight into the Store
         * @param {Array} data Array of data to load. Any non-model instances will be cast into model instances first
         * @param {Boolean} append True to add the records to the existing records in the store, false to remove the old ones first
         */
        loadData: function(data, append) {
            var model = this.model,
                length = data.length,
                i,
                record;

            //make sure each data element is an Ext.data.Model instance
            for (i = 0; i < length; i++) {
                record = data[i];

                if (! (record instanceof Ext.data.Model)) {
                    data[i] = Ext.ModelManager.create(record, model);
                }
            }

            this.loadRecords(data, {addRecords: append});
        },

        /**
         * Loads an array of {@Ext.data.Model model} instances into the store, fires the datachanged event. This should only usually
         * be called internally when loading from the {@link Ext.data.proxy.Proxy Proxy}, when adding records manually use {@link #add} instead
         * @param {Array} records The array of records to load
         * @param {Object} options {addRecords: true} to add these records to the existing records, false to remove the Store's existing records first
         */
        loadRecords: function(records, options) {
            var me     = this,
                i      = 0,
                length = records.length;

            options = options || {};

            if (!options.addRecords) {
                delete me.snapshot;
                me.clearData();
            }

            me.data.addAll(records);

            //FIXME: this is not a good solution. Ed Spencer is totally responsible for this and should be forced to fix it immediately.
            for (; i < length; i++) {
                if (options.start !== undefined) {
                    records[i].index = options.start + i;

                }
                records[i].join(me);
            }

            /*
             * this rather inelegant suspension and resumption of events is required because both the filter and sort functions
             * fire an additional datachanged event, which is not wanted. Ideally we would do this a different way. The first
             * datachanged event is fired by the call to this.add, above.
             */
            me.suspendEvents();

            if (me.filterOnLoad && !me.remoteFilter) {
                me.filter();
            }

            if (me.sortOnLoad && !me.remoteSort) {
                me.sort();
            }

            me.resumeEvents();
            me.fireEvent('datachanged', me, records);
        },

        // PAGING METHODS
        /**
         * Loads a given 'page' of data by setting the start and limit values appropriately. Internally this just causes a normal
         * load operation, passing in calculated 'start' and 'limit' params
         * @param {Number} page The number of the page to load
         */
        loadPage: function(page) {
            var me = this;

            me.currentPage = page;

            me.read({
                page: page,
                start: (page - 1) * me.pageSize,
                limit: me.pageSize,
                addRecords: !me.clearOnPageLoad
            });
        },

        /**
         * Loads the next 'page' in the current data set
         */
        nextPage: function() {
            this.loadPage(this.currentPage + 1);
        },

        /**
         * Loads the previous 'page' in the current data set
         */
        previousPage: function() {
            this.loadPage(this.currentPage - 1);
        },

        // private
        clearData: function() {
            this.data.each(function(record) {
                record.unjoin();
            });

            this.data.clear();
        },

        // Buffering
        /**
         * Prefetches data the Store using its configured {@link #proxy}.
         * @param {Object} options Optional config object, passed into the Ext.data.Operation object before loading.
         * See {@link #load}
         */
        prefetch: function(options) {
            var me = this,
                operation,
                requestId = me.getRequestId();

            options = options || {};

            Ext.applyIf(options, {
                action : 'read',
                filters: me.filters.items,
                sorters: me.sorters.items,
                requestId: requestId
            });
            me.pendingRequests.push(requestId);

            operation = Ext.create('Ext.data.Operation', options);

            // HACK to implement loadMask support.
            //if (operation.blocking) {
            //    me.fireEvent('beforeload', me, operation);
            //}
            if (me.fireEvent('beforeprefetch', me, operation) !== false) {
                me.loading = true;
                me.proxy.read(operation, me.onProxyPrefetch, me);
            }

            return me;
        },

        /**
         * Prefetches a page of data.
         * @param {Number} page The page to prefetch
         * @param {Object} options Optional config object, passed into the Ext.data.Operation object before loading.
         * See {@link #load}
         * @param
         */
        prefetchPage: function(page, options) {
            var me = this,
                pageSize = me.pageSize,
                start = (page - 1) * me.pageSize,
                end = start + pageSize;

            // Currently not requesting this page and range isn't already satisified
            if (Ext.Array.indexOf(me.pagesRequested, page) === -1 && !me.rangeSatisfied(start, end)) {
                options = options || {};
                me.pagesRequested.push(page);
                Ext.applyIf(options, {
                    page : page,
                    start: start,
                    limit: pageSize,
                    callback: me.onWaitForGuarantee,
                    scope: me
                });

                me.prefetch(options);
            }

        },

        /**
         * Returns a unique requestId to track requests.
         * @private
         */
        getRequestId: function() {
            this.requestSeed = this.requestSeed || 1;
            return this.requestSeed++;
        },

        /**
         * Handles a success pre-fetch
         * @private
         * @param {Ext.data.Operation} operation The operation that completed
         */
        onProxyPrefetch: function(operation) {
            var me         = this,
                resultSet  = operation.getResultSet(),
                records    = operation.getRecords(),

                successful = operation.wasSuccessful();

            if (resultSet) {
                me.totalCount = resultSet.total;
                me.fireEvent('totalcountchange', me.totalCount);
            }

            if (successful) {
                me.cacheRecords(records, operation);
            }
            Ext.Array.remove(me.pendingRequests, operation.requestId);
            if (operation.page) {
                Ext.Array.remove(me.pagesRequested, operation.page);
            }

            me.loading = false;
            me.fireEvent('prefetch', me, records, successful, operation);

            // HACK to support loadMask
            if (operation.blocking) {
                me.fireEvent('load', me, records, successful);
            }

            //this is a callback that would have been passed to the 'read' function and is optional
            Ext.callback(operation.callback, operation.scope || me, [records, operation, successful]);
        },

        /**
         * Caches the records in the prefetch and stripes them with their server-side
         * index.
         * @private
         * @param {Array} records The records to cache
         * @param {Ext.data.Operation} The associated operation
         */
        cacheRecords: function(records, operation) {
            var me     = this,
                i      = 0,
                length = records.length,
                start  = operation ? operation.start : 0;

            if (!Ext.isDefined(me.totalCount)) {
                me.totalCount = records.length;
                me.fireEvent('totalcountchange', me.totalCount);
            }

            for (; i < length; i++) {
                // this is the true index, not the viewIndex
                records[i].index = start + i;
            }

            me.prefetchData.addAll(records);
            if (me.purgePageCount) {
                me.purgeRecords();
            }

        },

        /**
         * Purge the least recently used records in the prefetch if the purgeCount
         * has been exceeded.
         */
        purgeRecords: function() {
            var me = this,
                prefetchCount = me.prefetchData.getCount(),
                purgeCount = me.purgePageCount * me.pageSize,
                numRecordsToPurge = prefetchCount - purgeCount - 1,
                i = 0;

            for (; i <= numRecordsToPurge; i++) {
                me.prefetchData.removeAt(0);
            }
        },

        /**
         * Determines if the range has already been satisfied in the prefetchData.
         * @private
         * @param {Number} start The start index
         * @param {Number} end The end index in the range
         */
        rangeSatisfied: function(start, end) {
            var me = this,
                i = start,
                satisfied = true;

            for (; i < end; i++) {
                if (!me.prefetchData.getByKey(i)) {
                    satisfied = false;
                    //<debug>
                    if (end - i > me.pageSize) {
                        Ext.Error.raise("A single page prefetch could never satisfy this request.");
                    }
                    //</debug>
                    break;
                }
            }
            return satisfied;
        },

        /**
         * Determines the page from a record index
         * @param {Number} index The record index
         * @return {Number} The page the record belongs to
         */
        getPageFromRecordIndex: function(index) {
            return Math.floor(index / this.pageSize) + 1;
        },

        /**
         * Handles a guaranteed range being loaded
         * @private
         */
        onGuaranteedRange: function() {
            var me = this,
                totalCount = me.getTotalCount(),
                start = me.requestStart,
                end = ((totalCount - 1) < me.requestEnd) ? totalCount - 1 : me.requestEnd,
                range = [],
                record,
                i = start;

            //<debug>
            if (start > end) {
                Ext.Error.raise("Start (" + start + ") was greater than end (" + end + ")");
            }
            //</debug>

            if (start !== me.guaranteedStart && end !== me.guaranteedEnd) {
                me.guaranteedStart = start;
                me.guaranteedEnd = end;

                for (; i <= end; i++) {
                    record = me.prefetchData.getByKey(i);
                    //<debug>
                    if (!record) {
                        Ext.Error.raise("Record was not found and store said it was guaranteed");
                    }
                    //</debug>
                    range.push(record);
                }
                me.fireEvent('guaranteedrange', range, start, end);
                if (me.cb) {
                    me.cb.call(me.scope || me, range);
                }
            }

            me.unmask();
        },

        // hack to support loadmask
        mask: function() {
            this.masked = true;
            this.fireEvent('beforeload');
        },

        // hack to support loadmask
        unmask: function() {
            if (this.masked) {
                this.fireEvent('load');
            }
        },

        /**
         * Returns the number of pending requests out.
         */
        hasPendingRequests: function() {
            return this.pendingRequests.length;
        },

        // wait until all requests finish, until guaranteeing the range.
        onWaitForGuarantee: function() {
            if (!this.hasPendingRequests()) {
                this.onGuaranteedRange();
            }
        },

        /**
         * Guarantee a specific range, this will load the store with a range (that
         * must be the pageSize or smaller) and take care of any loading that may
         * be necessary.
         */
        guaranteeRange: function(start, end, cb, scope) {
            //<debug>
            if (start && end) {
                if (end - start > this.pageSize) {
                    Ext.Error.raise({
                        start: start,
                        end: end,
                        pageSize: this.pageSize,
                        msg: "Requested a bigger range than the specified pageSize"
                    });
                }
            }
            //</debug>

            end = (end > this.totalCount) ? this.totalCount - 1 : end;

            var me = this,
                i = start,
                prefetchData = me.prefetchData,
                range = [],
                startLoaded = !!prefetchData.getByKey(start),
                endLoaded = !!prefetchData.getByKey(end),
                startPage = me.getPageFromRecordIndex(start),
                endPage = me.getPageFromRecordIndex(end);

            me.cb = cb;
            me.scope = scope;

            me.requestStart = start;
            me.requestEnd = end;
            // neither beginning or end are loaded
            if (!startLoaded || !endLoaded) {
                // same page, lets load it
                if (startPage === endPage) {
                    me.mask();
                    me.prefetchPage(startPage, {
                        //blocking: true,
                        callback: me.onWaitForGuarantee,
                        scope: me
                    });
                // need to load two pages
                } else {
                    me.mask();
                    me.prefetchPage(startPage, {
                        //blocking: true,
                        callback: me.onWaitForGuarantee,
                        scope: me
                    });
                    me.prefetchPage(endPage, {
                        //blocking: true,
                        callback: me.onWaitForGuarantee,
                        scope: me
                    });
                }
            // Request was already satisfied via the prefetch
            } else {
                me.onGuaranteedRange();
            }
        },

        // because prefetchData is stored by index
        // this invalidates all of the prefetchedData
        sort: function() {
            var me = this,
                prefetchData = me.prefetchData,
                sorters,
                start,
                end,
                range;

            if (me.buffered) {
                if (me.remoteSort) {
                    prefetchData.clear();
                    me.callParent(arguments);
                } else {
                    sorters = me.getSorters();
                    start = me.guaranteedStart;
                    end = me.guaranteedEnd;

                    if (sorters.length) {
                        prefetchData.sort(sorters);
                        range = prefetchData.getRange();
                        prefetchData.clear();
                        me.cacheRecords(range);
                        delete me.guaranteedStart;
                        delete me.guaranteedEnd;
                        me.guaranteeRange(start, end);
                    }
                    me.callParent(arguments);
                }
            } else {
                me.callParent(arguments);
            }
        },

        // overriden to provide striping of the indexes as sorting occurs.
        // this cannot be done inside of sort because datachanged has already
        // fired and will trigger a repaint of the bound view.
        doSort: function(sorterFn) {
            var me = this;
            if (me.remoteSort) {
                //the load function will pick up the new sorters and request the sorted data from the proxy
                me.load();
            } else {
                me.data.sortBy(sorterFn);
                if (!me.buffered) {
                    var range = me.getRange(),
                        ln = range.length,
                        i  = 0;
                    for (; i < ln; i++) {
                        range[i].index = i;
                    }
                }
                me.fireEvent('datachanged', me);
            }
        },

        /**
         * 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
         * @param {Boolean} exactMatch True to force exact match (^ and $ characters added to the regex). Defaults to false.
         * @return {Number} The matched index or -1
         */
        find: function(property, value, start, anyMatch, caseSensitive, exactMatch) {
            var fn = this.createFilterFn(property, value, anyMatch, caseSensitive, exactMatch);
            return fn ? this.data.findIndexBy(fn, null, start) : -1;
        },

        /**
         * Finds 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
         * @param {Boolean} exactMatch True to force exact match (^ and $ characters added to the regex). Defaults to false.
         * @return {Ext.data.Model} The matched record or null
         */
        findRecord: function() {
            var me = this,
                index = me.find.apply(me, arguments);
            return index !== -1 ? me.getAt(index) : null;
        },

        /**
         * @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)) {
                return false;
            }
            value = this.data.createValueMatcher(value, anyMatch, caseSensitive, exactMatch);
            return function(r) {
                return value.test(r.data[property]);
            };
        },

        /**
         * 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.Model<p class="sub-desc">The {@link Ext.data.Model record}
         * to test for filtering. Access field values using {@link Ext.data.Model#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 me = this,
                data = (bypassFilter === true && me.snapshot) ? me.snapshot: me.data;

            return data.collect(dataIndex, 'data', allowNull);
        },

        /**
         * 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;
        },

        /**
         * Returns the total number of {@link Ext.data.Model Model} instances that the {@link Ext.data.proxy.Proxy Proxy}
         * indicates exist. This will usually differ from {@link #getCount} when using paging - getCount returns the
         * number of records loaded into the Store at the moment, getTotalCount returns the number of records that
         * could be loaded into the Store if the Store contained all data
         * @return {Number} The total number of Model instances available via the Proxy
         */
        getTotalCount: function() {
            return this.totalCount;
        },

        /**
         * Get the Record at the specified index.
         * @param {Number} index The index of the Record to find.
         * @return {Ext.data.Model} The Record at the passed index. Returns undefined if not found.
         */
        getAt: function(index) {
            return this.data.getAt(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.Model[]} An array of Records
         */
        getRange: function(start, end) {
            return this.data.getRange(start, end);
        },

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

        /**
         * Get the index within the cache of the passed Record.
         * @param {Ext.data.Model} record The Ext.data.Model 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 entire dataset. From 0 to the totalCount.
         * @param {Ext.data.Model} record The Ext.data.Model object to find.
         * @return {Number} The index of the passed Record. Returns -1 if not found.
         */
        indexOfTotal: function(record) {
            return record.index || this.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);
        },

        /**
         * Remove all items from the store.
         * @param {Boolean} silent Prevent the `clear` event from being fired.
         */
        removeAll: function(silent) {
            var me = this;

            me.clearData();
            if (me.snapshot) {
                me.snapshot.clear();
            }
            if (silent !== true) {
                me.fireEvent('clear', me);
            }
        },

        /*
         * Aggregation methods
         */

        /**
         * Convenience function for getting the first model instance in the store
         * @param {Boolean} grouped (Optional) True to perform the operation for each group
         * in the store. The value returned will be an object literal with the key being the group
         * name and the first record being the value. The grouped parameter is only honored if
         * the store has a groupField.
         * @return {Ext.data.Model/undefined} The first model instance in the store, or undefined
         */
        first: function(grouped) {
            var me = this;

            if (grouped && me.isGrouped()) {
                return me.aggregate(function(records) {
                    return records.length ? records[0] : undefined;
                }, me, true);
            } else {
                return me.data.first();
            }
        },

        /**
         * Convenience function for getting the last model instance in the store
         * @param {Boolean} grouped (Optional) True to perform the operation for each group
         * in the store. The value returned will be an object literal with the key being the group
         * name and the last record being the value. The grouped parameter is only honored if
         * the store has a groupField.
         * @return {Ext.data.Model/undefined} The last model instance in the store, or undefined
         */
        last: function(grouped) {
            var me = this;

            if (grouped && me.isGrouped()) {
                return me.aggregate(function(records) {
                    var len = records.length;
                    return len ? records[len - 1] : undefined;
                }, me, true);
            } else {
                return me.data.last();
            }
        },

        /**
         * Sums the value of <tt>property</tt> for each {@link Ext.data.Model record} between <tt>start</tt>
         * and <tt>end</tt> and returns the result.
         * @param {String} field A field in each record
         * @param {Boolean} grouped (Optional) True to perform the operation for each group
         * in the store. The value returned will be an object literal with the key being the group
         * name and the sum for that group being the value. The grouped parameter is only honored if
         * the store has a groupField.
         * @return {Number} The sum
         */
        sum: function(field, grouped) {
            var me = this;

            if (grouped && me.isGrouped()) {
                return me.aggregate(me.getSum, me, true, [field]);
            } else {
                return me.getSum(me.data.items, field);
            }
        },

        // @private, see sum
        getSum: function(records, field) {
            var total = 0,
                i = 0,
                len = records.length;

            for (; i < len; ++i) {
                total += records[i].get(field);
            }

            return total;
        },

        /**
         * Gets the count of items in the store.
         * @param {Boolean} grouped (Optional) True to perform the operation for each group
         * in the store. The value returned will be an object literal with the key being the group
         * name and the count for each group being the value. The grouped parameter is only honored if
         * the store has a groupField.
         * @return {Number} the count
         */
        count: function(grouped) {
            var me = this;

            if (grouped && me.isGrouped()) {
                return me.aggregate(function(records) {
                    return records.length;
                }, me, true);
            } else {
                return me.getCount();
            }
        },

        /**
         * Gets the minimum value in the store.
         * @param {String} field The field in each record
         * @param {Boolean} grouped (Optional) True to perform the operation for each group
         * in the store. The value returned will be an object literal with the key being the group
         * name and the minimum in the group being the value. The grouped parameter is only honored if
         * the store has a groupField.
         * @return {Mixed/undefined} The minimum value, if no items exist, undefined.
         */
        min: function(field, grouped) {
            var me = this;

            if (grouped && me.isGrouped()) {
                return me.aggregate(me.getMin, me, true, [field]);
            } else {
                return me.getMin(me.data.items, field);
            }
        },

        // @private, see min
        getMin: function(records, field){
            var i = 1,
                len = records.length,
                value, min;

            if (len > 0) {
                min = records[0].get(field);
            }

            for (; i < len; ++i) {
                value = records[i].get(field);
                if (value < min) {
                    min = value;
                }
            }
            return min;
        },

        /**
         * Gets the maximum value in the store.
         * @param {String} field The field in each record
         * @param {Boolean} grouped (Optional) True to perform the operation for each group
         * in the store. The value returned will be an object literal with the key being the group
         * name and the maximum in the group being the value. The grouped parameter is only honored if
         * the store has a groupField.
         * @return {Mixed/undefined} The maximum value, if no items exist, undefined.
         */
        max: function(field, grouped) {
            var me = this;

            if (grouped && me.isGrouped()) {
                return me.aggregate(me.getMax, me, true, [field]);
            } else {
                return me.getMax(me.data.items, field);
            }
        },

        // @private, see max
        getMax: function(records, field) {
            var i = 1,
                len = records.length,
                value,
                max;

            if (len > 0) {
                max = records[0].get(field);
            }

            for (; i < len; ++i) {
                value = records[i].get(field);
                if (value > max) {
                    max = value;
                }
            }
            return max;
        },

        /**
         * Gets the average value in the store.
         * @param {String} field The field in each record
         * @param {Boolean} grouped (Optional) True to perform the operation for each group
         * in the store. The value returned will be an object literal with the key being the group
         * name and the group average being the value. The grouped parameter is only honored if
         * the store has a groupField.
         * @return {Mixed/undefined} The average value, if no items exist, 0.
         */
        average: function(field, grouped) {
            var me = this;
            if (grouped && me.isGrouped()) {
                return me.aggregate(me.getAverage, me, true, [field]);
            } else {
                return me.getAverage(me.data.items, field);
            }
        },

        // @private, see average
        getAverage: function(records, field) {
            var i = 0,
                len = records.length,
                sum = 0;

            if (records.length > 0) {
                for (; i < len; ++i) {
                    sum += records[i].get(field);
                }
                return sum / len;
            }
            return 0;
        },

        /**
         * Runs the aggregate function for all the records in the store.
         * @param {Function} fn The function to execute. The function is called with a single parameter,
         * an array of records for that group.
         * @param {Object} scope (optional) The scope to execute the function in. Defaults to the store.
         * @param {Boolean} grouped (Optional) True to perform the operation for each group
         * in the store. The value returned will be an object literal with the key being the group
         * name and the group average being the value. The grouped parameter is only honored if
         * the store has a groupField.
         * @param {Array} args (optional) Any arguments to append to the function call
         * @return {Object} An object literal with the group names and their appropriate values.
         */
        aggregate: function(fn, scope, grouped, args) {
            args = args || [];
            if (grouped && this.isGrouped()) {
                var groups = this.getGroups(),
                    i = 0,
                    len = groups.length,
                    out = {},
                    group;

                for (; i < len; ++i) {
                    group = groups[i];
                    out[group.name] = fn.apply(scope || this, [group.children].concat(args));
                }
                return out;
            } else {
                return fn.apply(scope || this, [this.data.items].concat(args));
            }
        }
    });