    Observable
      Provider
        JsonProvider
          PollingProvider

# Class Ext.direct.PollingProvider

Package: | Ext.direct
Defined In: | PollingProvider.js
Class: | PollingProvider
Extends: | JsonProvider

Provides for repetitive polling of the server at distinct intervals. The initial request for data originates from the client, and then is responded to by the server.

All configurations for the PollingProvider should be generated by the server-side API portion of the Ext.Direct stack.

An instance of PollingProvider may be created directly via the new keyword or by simply specifying `type = 'polling'`. For example:

    var pollA = new Ext.direct.PollingProvider({
        type:'polling',
        url: 'php/pollA.php',
    });
    Ext.Direct.addProvider(pollA);
    pollA.disconnect();

    Ext.Direct.addProvider(
        {
            type:'polling',
            url: 'php/pollB.php',
            id: 'pollB-provider'
        }
    );
    var pollB = Ext.Direct.getProvider('pollB-provider');

## Config Options

Config Options | Defined By
--- | ---
| baseParams : Object An object containing properties which are to be sent as parameters on every polling request | PollingProvider

id : String
The unique id of the provider (defaults to an auto-assigned id). You should assign an id if you need to be able to a...
The unique id of the provider (defaults to an 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 = Ext.Direct.getProvider('poll-provider');
    p.disconnect();

Provider

| interval : Number How often to poll the server-side in milliseconds (defaults to `3000` - every 3 seconds). | PollingProvider

listeners : Object
A config object containing one or more event handlers to be added to this object during initialization. This should ...

A config object containing one or more event handlers to be added to this object during initialization. This should be a valid listeners config object as specified in the addListener example for attaching multiple handlers at once.

DOM events from ExtJs Components

While some ExtJs Component classes export selected DOM events (e.g. "click", "mouseover" etc), this is usually only done when extra value can be added. For example the DataView's `click` event passing the node clicked on. To access DOM events directly from a Component's HTMLElement, listeners must be added to the Element after the Component has been rendered. A plugin can simplify this step:

    // Plugin is configured with a listeners config object.
    // The Component is appended to the argument list of all handler functions.
    Ext.DomObserver = Ext.extend(Object, {
        constructor: function(config) {
            this.listeners = config.listeners ? config.listeners : config;
        },

        // Component passes itself into plugin's init method
        init: function(c) {
            var p, l = this.listeners;
            for (p in l) {
                if (Ext.isFunction(l[p])) {
                    l[p] = this.createHandler(l[p], c);
                } else {
                    l[p].fn = this.createHandler(l[p].fn, c);
                }
            }

            // Add the listeners to the Element immediately following the render call
            c.render = c.render.createSequence(function() {
                var e = c.getEl();
                if (e) {
                    e.on(l);
                }
            });
        },

        createHandler: function(fn, c) {
            return function(e) {
                fn.call(this, e, c);
            };
        }
    });

    var combo = new Ext.form.ComboBox({

        // Collapse combo when its element is clicked on
        plugins: [ new Ext.DomObserver({
            click: function(evt, comp) {
                comp.collapse();
            }
        })],
        store: myStore,
        typeAhead: true,
        mode: 'local',
        triggerAction: 'all'
    });

Observable

| priority : Number Priority of the request (defaults to `3`). See Ext.direct.Provider.priority. | PollingProvider

type : String
Required, undefined by default. The type of provider specified to Ext.Direct.addProvider to create a new Provider....
Required, `undefined` by default. The `type` of provider specified to Ext.Direct.addProvider to create a new Provider. Acceptable values by default are:

- `polling` : PollingProvider
- `remoting` : RemotingProvider

Provider

| url : String/Function The url which the PollingProvider should contact with each request. This can also be an imported Ext.Direct method w... The url which the PollingProvider should contact with each request. This can also be an imported Ext.Direct method which will accept the baseParams as its only argument. | PollingProvider

## Public Properties

Property | Defined By
--- | ---
| connect : Object Abstract methods for subclasses to implement. | Provider
| disconnect : Object Abstract methods for subclasses to implement. | Provider

## Public Methods

Method | Defined By
--- | ---

addEvents( `Object|String o`, `string Optional.` ) : void
Adds the specified events to the list of events which this Observable may fire.
Adds the specified events to the list of events which this Observable may fire.
Parameters:

- `o` : Object|String
  Either an object with event names as properties with a value of `true` or the first event name string if multiple event names are being passed as separate parameters.
- `Optional.` : string
  Event name if multiple event names are being passed as separate parameters. Usage:

      this.addEvents('storeloaded', 'storecleared');

Returns:

- void

Observable

addListener( `String eventName`, `Function handler`, [`Object scope`], [`Object options`] ) : void
Appends an event handler to this object.
Appends an event handler to this object.
Parameters:

- `eventName` : String
  The name of the event to listen for.
- `handler` : Function
  The method the event invokes.
- `scope` : Object
  (optional) The scope (`this` reference) in which the handler function is executed. If omitted, defaults to the object which fired the event.
- `options` : Object
  (optional) An object containing handler configuration. properties. This may contain any of the following properties:
  - scope : Object
    The scope (`this` reference) in which the handler function is executed. If omitted, defaults to the object which fired the event.
  - delay : Number
    The number of milliseconds to delay the invocation of the handler after the event fires.
  - single : Boolean
    True to add a handler to handle just the next firing of the event, and then remove itself.
  - buffer : Number
    Causes the handler to be scheduled to run in an Ext.util.DelayedTask delayed by the specified number of milliseconds. If the event fires again within that time, the original handler is not invoked, but the new handler is scheduled in its place.
  - target : Observable
    Only call the handler if the event was fired on the target Observable, not if the event was bubbled up from a child Observable.

  Combining Options
  Using the options argument, it is possible to combine different types of listeners:
  A delayed, one-time listener.

      myDataView.on('click', this.onClick, this, {
      single: true,
      delay: 100
      });

  Attaching multiple handlers in 1 call
  The method also allows for a single argument to be passed which is a config object containing properties which specify multiple handlers.

      myGridPanel.on({
      'click' : {
          fn: this.onClick,
          scope: this,
          delay: 100
      },
      'mouseover' : {
          fn: this.onMouseOver,
          scope: this
      },
      'mouseout' : {
          fn: this.onMouseOut,
          scope: this
      }
      });

  Or a shorthand syntax:

      myGridPanel.on({
      'click' : this.onClick,
      'mouseover' : this.onMouseOver,
      'mouseout' : this.onMouseOut,
       scope: this
      });

Returns:

- void

Observable

connect() : void
Connect to the server-side and begin the polling process. To handle each response subscribe to the data event.
Connect to the server-side and begin the polling process. To handle each response subscribe to the data event.
Parameters:

- None.

Returns:

- void

PollingProvider

disconnect() : void
Disconnect from the server-side and stop the polling process. The disconnect event will be fired on a successful dis...
Disconnect from the server-side and stop the polling process. The disconnect event will be fired on a successful disconnect.
Parameters:

- None.

Returns:

- void

PollingProvider

enableBubble( `String/Array events` ) : void
Enables events fired by this Observable to bubble up an owner hierarchy by calling this.getBubbleTarget() if present...

Enables events fired by this Observable to bubble up an owner hierarchy by calling `this.getBubbleTarget()` if present. There is no implementation in the Observable base class.

This is commonly used by Ext.Components to bubble events to owner Containers. See Ext.Component.getBubbleTarget. The default implementation in Ext.Component returns the Component's immediate owner. But if a known target is required, this can be overridden to access the required target more quickly.

Example:

    Ext.override(Ext.form.Field, {
        //  Add functionality to Field's initComponent to enable the change event to bubble

        initComponent : Ext.form.Field.prototype.initComponent.createSequence(function() {
            this.enableBubble('change');
        }),

        //  We know that we want Field's events to bubble directly to the FormPanel.

        getBubbleTarget : function() {
            if (!this.formPanel) {
                this.formPanel = this.findParentByType('form');
            }
            return this.formPanel;
        }
    });

    var myForm = new Ext.formPanel({
        title: 'User Details',
        items: [{
            ...
        }],
        listeners: {
            change: function() {
                // Title goes red if form has been modified.

                myForm.header.setStyle('color', 'red');
            }
        }
    });

Parameters:

- `events` : String/Array
  The event name to bubble, or an Array of event names.

Returns:

- void

Observable

fireEvent( `String eventName`, `Object... args` ) : Boolean
Fires the specified event with the passed parameters (minus the event name). An event may be set to bubble up an Obse...

Fires the specified event with the passed parameters (minus the event name).

An event may be set to bubble up an Observable parent hierarchy (See Ext.Component.getBubbleTarget) by calling enableBubble.

Parameters:

- `eventName` : String
  The name of the event to fire.
- `args` : Object...
  Variable number of parameters are passed to handlers.

Returns:

- `Boolean`
  returns false if any of the handlers return false otherwise it returns true.

Observable

hasListener( `String eventName` ) : Boolean
Checks to see if this object has any listeners for a specified event
Checks to see if this object has any listeners for a specified event
Parameters:

- `eventName` : String
  The name of the event to check for

Returns:

- `Boolean`
  True if the event is being listened for, else false

Observable

isConnected() : void
Returns whether or not the server-side is currently connected. Abstract method for subclasses to implement.
Returns whether or not the server-side is currently connected. Abstract method for subclasses to implement.
Parameters:

- None.

Returns:

- void

Provider

on( `String eventName`, `Function handler`, [`Object scope`], [`Object options`] ) : void
Appends an event handler to this object (shorthand for addListener.)
Appends an event handler to this object (shorthand for addListener.)
Parameters:

- `eventName` : String
  The type of event to listen for
- `handler` : Function
  The method the event invokes
- `scope` : Object
  (optional) The scope (`this` reference) in which the handler function is executed. If omitted, defaults to the object which fired the event.
- `options` : Object
  (optional) An object containing handler configuration.

Returns:

- void

Observable

purgeListeners() : void
Removes all listeners for this object
Removes all listeners for this object
Parameters:

- None.

Returns:

- void

Observable

relayEvents( `Object o`, `Array events` ) : void
Relays selected events from the specified Observable as if the events were fired by this.
Relays selected events from the specified Observable as if the events were fired by `this`.
Parameters:

- `o` : Object
  The Observable whose events this object is to relay.
- `events` : Array
  Array of event names to relay.

Returns:

- void

Observable

removeListener( `String eventName`, `Function handler`, [`Object scope`] ) : void
Removes an event handler.
Removes an event handler.
Parameters:

- `eventName` : String
  The type of event the handler was associated with.
- `handler` : Function
  The handler to remove. This must be a reference to the function passed into the addListener call.
- `scope` : Object
  (optional) The scope originally specified for the handler.

Returns:

- void

Observable

resumeEvents() : void
Resume firing events. (see suspendEvents) If events were suspended using the queueSuspended parameter, then all event...
Resume firing events. (see suspendEvents) If events were suspended using the `queueSuspended` parameter, then all events fired during event suspension will be sent to any listeners now.
Parameters:

- None.

Returns:

- void

Observable

suspendEvents( `Boolean queueSuspended` ) : void
Suspend the firing of all events. (see resumeEvents)
Suspend the firing of all events. (see resumeEvents)
Parameters:

- `queueSuspended` : Boolean
  Pass as true to queue up suspended events to be fired after the resumeEvents call instead of discarding all suspended events;

Returns:

- void

Observable

un( `String eventName`, `Function handler`, [`Object scope`] ) : void
Removes an event handler (shorthand for removeListener.)
Removes an event handler (shorthand for removeListener.)
Parameters:

- `eventName` : String
  The type of event the handler was associated with.
- `handler` : Function
  The handler to remove. This must be a reference to the function passed into the addListener call.
- `scope` : Object
  (optional) The scope originally specified for the handler.

Returns:

- void

Observable

## Public Events

Event | Defined By
--- | ---

beforepoll : ( `Ext.direct.PollingProvider` )
Fired immediately before a poll takes place, an event handler can return false in order to cancel the poll.
Fired immediately before a poll takes place, an event handler can return false in order to cancel the poll.
Listeners will be called with the following arguments:

- `` : Ext.direct.PollingProvider

PollingProvider

connect : ( `Ext.direct.Provider provider` )
Fires when the Provider connects to the server-side
Fires when the Provider connects to the server-side
Listeners will be called with the following arguments:

- `provider` : Ext.direct.Provider
  The Provider.

Provider

data : ( `Ext.direct.Provider provider`, `event e` )
Fires when the Provider receives data from the server-side
Fires when the Provider receives data from the server-side
Listeners will be called with the following arguments:

- `provider` : Ext.direct.Provider
  The Provider.
- `e` : event
  The Ext.Direct.Event type that occurred.

Provider

disconnect : ( `Ext.direct.Provider provider` )
Fires when the Provider disconnects from the server-side
Fires when the Provider disconnects from the server-side
Listeners will be called with the following arguments:

- `provider` : Ext.direct.Provider
  The Provider.

Provider

exception : ()
Fires when the Provider receives an exception from the server-side
Fires when the Provider receives an exception from the server-side
Listeners will be called with the following arguments:

- None.

Provider

poll : ( `Ext.direct.PollingProvider` )
This event has not yet been implemented.
This event has not yet been implemented.
Listeners will be called with the following arguments:

- `` : Ext.direct.PollingProvider

PollingProvider