    /**
     * Ext.Direct aims to streamline communication between the client and server by providing a single interface that
     * reduces the amount of common code typically required to validate data and handle returned data packets (reading data,
     * error conditions, etc).
     *
     * The Ext.direct namespace includes several classes for a closer integration with the server-side. The Ext.data
     * namespace also includes classes for working with Ext.data.Stores which are backed by data from an Ext.Direct method.
     *
     * # Specification
     *
     * For additional information consult the [Ext.Direct Specification][1].
     *
     * # Providers
     *
     * Ext.Direct uses a provider architecture, where one or more providers are used to transport data to and from the
     * server. There are several providers that exist in the core at the moment:
     *
     * - {@link Ext.direct.JsonProvider JsonProvider} for simple JSON operations
     * - {@link Ext.direct.PollingProvider PollingProvider} for repeated requests
     * - {@link Ext.direct.RemotingProvider RemotingProvider} exposes server side on the client.
     *
     * A provider does not need to be invoked directly, providers are added via {@link Ext.direct.Manager}.{@link #addProvider}.
     *
     * # Router
     *
     * Ext.Direct utilizes a "router" on the server to direct requests from the client to the appropriate server-side
     * method. Because the Ext.Direct API is completely platform-agnostic, you could completely swap out a Java based server
     * solution and replace it with one that uses C# without changing the client side JavaScript at all.
     *
     * # Server side events
     *
     * Custom events from the server may be handled by the client by adding listeners, for example:
     *
     *     {"type":"event","name":"message","data":"Successfully polled at: 11:19:30 am"}
     *
     *     // add a handler for a 'message' event sent by the server
     *     Ext.direct.Manager.on('message', function(e){
     *         out.append(String.format('<p><i>{0}</i></p>', e.data));
     *         out.el.scrollTo('t', 100000, true);
     *     });
     *
     *    [1]: http://sencha.com/products/extjs/extdirect
     *
     * @singleton
     * @alternateClassName Ext.Direct
     */
    Ext.define('Ext.direct.Manager', {

        /* Begin Definitions */
        singleton: true,

        mixins: {
            observable: 'Ext.util.Observable'
        },

        requires: ['Ext.util.MixedCollection'],

        statics: {
            exceptions: {
                TRANSPORT: 'xhr',
                PARSE: 'parse',
                LOGIN: 'login',
                SERVER: 'exception'
            }
        },

        /* End Definitions */

        constructor: function(){
            var me = this;

            me.addEvents(
                /**
                 * @event event
                 * Fires after an event.
                 * @param {Ext.direct.Event} e The Ext.direct.Event type that occurred.
                 * @param {Ext.direct.Provider} provider The {@link Ext.direct.Provider Provider}.
                 */
                'event',
                /**
                 * @event exception
                 * Fires after an event exception.
                 * @param {Ext.direct.Event} e The event type that occurred.
                 */
                'exception'
            );
            me.transactions = Ext.create('Ext.util.MixedCollection');
            me.providers = Ext.create('Ext.util.MixedCollection');

            me.mixins.observable.constructor.call(me);
        },

        /**
         * Adds an Ext.Direct Provider and creates the proxy or stub methods to execute server-side methods. If the provider
         * is not already connected, it will auto-connect.
         *
         *     var pollProv = new Ext.direct.PollingProvider({
         *         url: 'php/poll2.php'
         *     });
         *
         *     Ext.direct.Manager.addProvider({
         *         "type":"remoting",       // create a {@link Ext.direct.RemotingProvider}
         *         "url":"php\/router.php", // url to connect to the Ext.Direct server-side router.
         *         "actions":{              // each property within the actions object represents a Class
         *             "TestAction":[       // array of methods within each server side Class
         *             {
         *                 "name":"doEcho", // name of method
         *                 "len":1
         *             },{
         *                 "name":"multiply",
         *                 "len":1
         *             },{
         *                 "name":"doForm",
         *                 "formHandler":true, // handle form on server with Ext.Direct.Transaction
         *                 "len":1
         *             }]
         *         },
         *         "namespace":"myApplication",// namespace to create the Remoting Provider in
         *     },{
         *         type: 'polling', // create a {@link Ext.direct.PollingProvider}
         *         url:  'php/poll.php'
         *     }, pollProv); // reference to previously created instance
         *
         * @param {Ext.direct.Provider/Object...} provider
         * Accepts any number of Provider descriptions (an instance or config object for
         * a Provider). Each Provider description instructs Ext.Directhow to create
         * client-side stub methods.
         */
        addProvider : function(provider){
            var me = this,
                args = arguments,
                i = 0,
                len;

            if (args.length > 1) {
                for (len = args.length; i < len; ++i) {
                    me.addProvider(args[i]);
                }
                return;
            }

            // if provider has not already been instantiated
            if (!provider.isProvider) {
                provider = Ext.create('direct.' + provider.type + 'provider', provider);
            }
            me.providers.add(provider);
            provider.on('data', me.onProviderData, me);

            if (!provider.isConnected()) {
                provider.connect();
            }

            return provider;
        },

        /**
         * Retrieves a {@link Ext.direct.Provider provider} by the **{@link Ext.direct.Provider#id id}** specified when the
         * provider is {@link #addProvider added}.
         * @param {String/Ext.direct.Provider} id The id of the provider, or the provider instance.
         */
        getProvider : function(id){
            return id.isProvider ? id : this.providers.get(id);
        },

        /**
         * Removes the provider.
         * @param {String/Ext.direct.Provider} provider The provider instance or the id of the provider.
         * @return {Ext.direct.Provider} The provider, null if not found.
         */
        removeProvider : function(provider){
            var me = this,
                providers = me.providers;

            provider = provider.isProvider ? provider : providers.get(provider);

            if (provider) {
                provider.un('data', me.onProviderData, me);
                providers.remove(provider);
                return provider;
            }
            return null;
        },

        /**
         * Adds a transaction to the manager.
         * @private
         * @param {Ext.direct.Transaction} transaction The transaction to add
         * @return {Ext.direct.Transaction} transaction
         */
        addTransaction: function(transaction){
            this.transactions.add(transaction);
            return transaction;
        },

        /**
         * Removes a transaction from the manager.
         * @private
         * @param {String/Ext.direct.Transaction} transaction The transaction/id of transaction to remove
         * @return {Ext.direct.Transaction} transaction
         */
        removeTransaction: function(transaction){
            transaction = this.getTransaction(transaction);
            this.transactions.remove(transaction);
            return transaction;
        },

        /**
         * Gets a transaction
         * @private
         * @param {String/Ext.direct.Transaction} transaction The transaction/id of transaction to get
         * @return {Ext.direct.Transaction}
         */
        getTransaction: function(transaction){
            return transaction.isTransaction ? transaction : this.transactions.get(transaction);
        },

        onProviderData : function(provider, event){
            var me = this,
                i = 0,
                len;

            if (Ext.isArray(event)) {
                for (len = event.length; i < len; ++i) {
                    me.onProviderData(provider, event[i]);
                }
                return;
            }
            if (event.name && event.name != 'event' && event.name != 'exception') {
                me.fireEvent(event.name, event);
            } else if (event.status === false) {
                me.fireEvent('exception', event);
            }
            me.fireEvent('event', event, provider);
        }
    }, function(){
        // Backwards compatibility
        Ext.Direct = Ext.direct.Manager;
    });