/**
 * @class Ext.direct.Provider
 * @extends Ext.util.Observable
 * 
Ext.direct.Provider is an abstract class meant to be extended.
 * 
 * 
For example ExtJs implements the following subclasses:
 * 

Provider
|
+---{@link Ext.direct.JsonProvider JsonProvider} 
    |
    +---{@link Ext.direct.PollingProvider PollingProvider}   
    |
    +---{@link Ext.direct.RemotingProvider RemotingProvider}   
 * 
 * @abstract
 */
Ext.direct.Provider = Ext.extend(Ext.util.Observable, {    
    
/**
     * @cfg {String} id
     * The unique id of the provider (defaults to an {@link Ext#id auto-assigned id}).
     * You should assign an id if you need to be able to access the provider later and you do
     * not have an object reference available, for example:
     * 

Ext.Direct.addProvider(
    {
        type: 'polling',
        url:  'php/poll.php',
        id:   'poll-provider'
    }
);
     
var p = {@link Ext.Direct Ext.Direct}.{@link Ext.Direct#getProvider getProvider}('poll-provider');
p.disconnect();
     * 
     */
        
    
/**
     * @cfg {Number} priority
     * Priority of the request. Lower is higher priority, 0 means "duplex" (always on).
     * All Providers default to 1 except for PollingProvider which defaults to 3.
     */    
    priority: 1,

    
/**
     * @cfg {String} type
     * Required, undefined by default.  The type of provider specified
     * to {@link Ext.Direct Ext.Direct}.{@link Ext.Direct#addProvider addProvider} to create a
     * new Provider. Acceptable values by default are:

     * 
polling : {@link Ext.direct.PollingProvider PollingProvider}
     * 
remoting : {@link Ext.direct.RemotingProvider RemotingProvider}
     * 
     */    
 
    // private
    constructor : function(config){
        Ext.apply(this, config);
        this.addEvents(
            
/**
             * @event connect
             * Fires when the Provider connects to the server-side
             * @param {Ext.direct.Provider} provider The {@link Ext.direct.Provider Provider}.
             */            
            'connect',
            
/**
             * @event disconnect
             * Fires when the Provider disconnects from the server-side
             * @param {Ext.direct.Provider} provider The {@link Ext.direct.Provider Provider}.
             */            
            'disconnect',
            
/**
             * @event data
             * Fires when the Provider receives data from the server-side
             * @param {Ext.direct.Provider} provider The {@link Ext.direct.Provider Provider}.
             * @param {event} e The {@link Ext.Direct#eventTypes Ext.Direct.Event type} that occurred.
             */            
            'data',
            
/**
             * @event exception
             * Fires when the Provider receives an exception from the server-side
             */                        
            'exception'
        );
        Ext.direct.Provider.superclass.constructor.call(this, config);
    },

    
/**
     * Returns whether or not the server-side is currently connected.
     * Abstract method for subclasses to implement.
     */
    isConnected: function(){
        return false;
    },

    
/**
     * Abstract methods for subclasses to implement.
     */
    connect: Ext.emptyFn,
    
    
/**
     * Abstract methods for subclasses to implement.
     */
    disconnect: Ext.emptyFn
});