    /**
     * @author Ed Spencer
     * @class Ext.data.proxy.Proxy
     *
     * <p>Proxies are used by {@link Ext.data.Store Stores} to handle the loading and saving of {@link Ext.data.Model Model} data.
     * Usually developers will not need to create or interact with proxies directly.</p>
     * <p><u>Types of Proxy</u></p>
     *
     * <p>There are two main types of Proxy - {@link Ext.data.proxy.Client Client} and {@link Ext.data.proxy.Server Server}. The Client proxies
     * save their data locally and include the following subclasses:</p>
     *
     * <ul style="list-style-type: disc; padding-left: 25px">
     * <li>{@link Ext.data.proxy.LocalStorage LocalStorageProxy} - saves its data to localStorage if the browser supports it</li>
     * <li>{@link Ext.data.proxy.SessionStorage SessionStorageProxy} - saves its data to sessionStorage if the browsers supports it</li>
     * <li>{@link Ext.data.proxy.Memory MemoryProxy} - holds data in memory only, any data is lost when the page is refreshed</li>
     * </ul>
     *
     * <p>The Server proxies save their data by sending requests to some remote server. These proxies include:</p>
     *
     * <ul style="list-style-type: disc; padding-left: 25px">
     * <li>{@link Ext.data.proxy.Ajax Ajax} - sends requests to a server on the same domain</li>
     * <li>{@link Ext.data.proxy.JsonP JsonP} - uses JSON-P to send requests to a server on a different domain</li>
     * <li>{@link Ext.data.proxy.Direct Direct} - uses {@link Ext.direct} to send requests</li>
     * </ul>
     *
     * <p>Proxies operate on the principle that all operations performed are either Create, Read, Update or Delete. These four operations
     * are mapped to the methods {@link #create}, {@link #read}, {@link #update} and {@link #destroy} respectively. Each Proxy subclass
     * implements these functions.</p>
     *
     * <p>The CRUD methods each expect an {@link Ext.data.Operation Operation} object as the sole argument. The Operation encapsulates
     * information about the action the Store wishes to perform, the {@link Ext.data.Model model} instances that are to be modified, etc.
     * See the {@link Ext.data.Operation Operation} documentation for more details. Each CRUD method also accepts a callback function to be
     * called asynchronously on completion.</p>
     *
     * <p>Proxies also support batching of Operations via a {@link Ext.data.Batch batch} object, invoked by the {@link #batch} method.</p>
     *
     * @constructor
     * Creates the Proxy
     * @param {Object} config Optional config object
     */
    Ext.define('Ext.data.proxy.Proxy', {
        alias: 'proxy.proxy',
        alternateClassName: ['Ext.data.DataProxy', 'Ext.data.Proxy'],
        requires: [
            'Ext.data.reader.Json',
            'Ext.data.writer.Json'
        ],
        uses: [
            'Ext.data.Batch',
            'Ext.data.Operation',
            'Ext.data.Model'
        ],
        mixins: {
            observable: 'Ext.util.Observable'
        },

        /**
         * @cfg {String} batchOrder
         * Comma-separated ordering 'create', 'update' and 'destroy' actions when batching. Override this
         * to set a different order for the batched CRUD actions to be executed in. Defaults to 'create,update,destroy'
         */
        batchOrder: 'create,update,destroy',

        /**
         * @cfg {Boolean} batchActions True to batch actions of a particular type when synchronizing the store.
         * Defaults to <tt>true</tt>.
         */
        batchActions: true,

        /**
         * @cfg {String} defaultReaderType The default registered reader type. Defaults to 'json'
         * @private
         */
        defaultReaderType: 'json',

        /**
         * @cfg {String} defaultWriterType The default registered writer type. Defaults to 'json'
         * @private
         */
        defaultWriterType: 'json',

        /**
         * @cfg {String/Ext.data.Model} model The name of the Model to tie to this Proxy. Can be either the string name of
         * the Model, or a reference to the Model constructor. Required.
         */

        isProxy: true,

        constructor: function(config) {
            config = config || {};

            if (config.model === undefined) {
                delete config.model;
            }

            this.mixins.observable.constructor.call(this, config);

            if (this.model !== undefined && !(this.model instanceof Ext.data.Model)) {
                this.setModel(this.model);
            }
        },

        /**
         * Sets the model associated with this proxy. This will only usually be called by a Store
         * @param {String|Ext.data.Model} model The new model. Can be either the model name string,
         * or a reference to the model's constructor
         * @param {Boolean} setOnStore Sets the new model on the associated Store, if one is present
         */
        setModel: function(model, setOnStore) {
            this.model = Ext.ModelManager.getModel(model);

            var reader = this.reader,
                writer = this.writer;

            this.setReader(reader);
            this.setWriter(writer);

            if (setOnStore && this.store) {
                this.store.setModel(this.model);
            }
        },

        /**
         * Returns the model attached to this Proxy
         * @return {Ext.data.Model} The model
         */
        getModel: function() {
            return this.model;
        },

        /**
         * Sets the Proxy's Reader by string, config object or Reader instance
         * @param {String|Object|Ext.data.reader.Reader} reader The new Reader, which can be either a type string, a configuration object
         * or an Ext.data.reader.Reader instance
         * @return {Ext.data.reader.Reader} The attached Reader object
         */
        setReader: function(reader) {
            var me = this;

            if (reader === undefined || typeof reader == 'string') {
                reader = {
                    type: reader
                };
            }

            if (reader.isReader) {
                reader.setModel(me.model);
            } else {
                Ext.applyIf(reader, {
                    proxy: me,
                    model: me.model,
                    type : me.defaultReaderType
                });

                reader = Ext.createByAlias('reader.' + reader.type, reader);
            }

            me.reader = reader;
            return me.reader;
        },

        /**
         * Returns the reader currently attached to this proxy instance
         * @return {Ext.data.reader.Reader} The Reader instance
         */
        getReader: function() {
            return this.reader;
        },

        /**
         * Sets the Proxy's Writer by string, config object or Writer instance
         * @param {String|Object|Ext.data.writer.Writer} writer The new Writer, which can be either a type string, a configuration object
         * or an Ext.data.writer.Writer instance
         * @return {Ext.data.writer.Writer} The attached Writer object
         */
        setWriter: function(writer) {
            if (writer === undefined || typeof writer == 'string') {
                writer = {
                    type: writer
                };
            }

            if (!(writer instanceof Ext.data.writer.Writer)) {
                Ext.applyIf(writer, {
                    model: this.model,
                    type : this.defaultWriterType
                });

                writer = Ext.createByAlias('writer.' + writer.type, writer);
            }

            this.writer = writer;

            return this.writer;
        },

        /**
         * Returns the writer currently attached to this proxy instance
         * @return {Ext.data.writer.Writer} The Writer instance
         */
        getWriter: function() {
            return this.writer;
        },

        /**
         * Performs the given create operation.
         * @param {Ext.data.Operation} operation The Operation to perform
         * @param {Function} callback Callback function to be called when the Operation has completed (whether successful or not)
         * @param {Object} scope Scope to execute the callback function in
         */
        create: Ext.emptyFn,

        /**
         * Performs the given read operation.
         * @param {Ext.data.Operation} operation The Operation to perform
         * @param {Function} callback Callback function to be called when the Operation has completed (whether successful or not)
         * @param {Object} scope Scope to execute the callback function in
         */
        read: Ext.emptyFn,

        /**
         * Performs the given update operation.
         * @param {Ext.data.Operation} operation The Operation to perform
         * @param {Function} callback Callback function to be called when the Operation has completed (whether successful or not)
         * @param {Object} scope Scope to execute the callback function in
         */
        update: Ext.emptyFn,

        /**
         * Performs the given destroy operation.
         * @param {Ext.data.Operation} operation The Operation to perform
         * @param {Function} callback Callback function to be called when the Operation has completed (whether successful or not)
         * @param {Object} scope Scope to execute the callback function in
         */
        destroy: Ext.emptyFn,

        /**
         * Performs a batch of {@link Ext.data.Operation Operations}, in the order specified by {@link #batchOrder}. Used internally by
         * {@link Ext.data.Store}'s {@link Ext.data.Store#sync sync} method. Example usage:
         * <pre><code>
         * myProxy.batch({
         *     create : [myModel1, myModel2],
         *     update : [myModel3],
         *     destroy: [myModel4, myModel5]
         * });
         * </code></pre>
         * Where the myModel* above are {@link Ext.data.Model Model} instances - in this case 1 and 2 are new instances and have not been
         * saved before, 3 has been saved previously but needs to be updated, and 4 and 5 have already been saved but should now be destroyed.
         * @param {Object} operations Object containing the Model instances to act upon, keyed by action name
         * @param {Object} listeners Optional listeners object passed straight through to the Batch - see {@link Ext.data.Batch}
         * @return {Ext.data.Batch} The newly created Ext.data.Batch object
         */
        batch: function(operations, listeners) {
            var me = this,
                batch = Ext.create('Ext.data.Batch', {
                    proxy: me,
                    listeners: listeners || {}
                }),
                useBatch = me.batchActions,
                records;

            Ext.each(me.batchOrder.split(','), function(action) {
                records = operations[action];
                if (records) {
                    if (useBatch) {
                        batch.add(Ext.create('Ext.data.Operation', {
                            action: action,
                            records: records
                        }));
                    } else {
                        Ext.each(records, function(record){
                            batch.add(Ext.create('Ext.data.Operation', {
                                action : action,
                                records: [record]
                            }));
                        });
                    }
                }
            }, me);

            batch.start();
            return batch;
        }
    }, function() {
        // Ext.data.proxy.ProxyMgr.registerType('proxy', this);

        //backwards compatibility
        Ext.data.DataProxy = this;
        // Ext.deprecate('platform', '2.0', function() {
        //     Ext.data.DataProxy = this;
        // }, this);
    });