mx.utils

# ObjectProxy - AS3 Flex

Package | mx.utils
Class | public dynamic class ObjectProxy
Inheritance | ObjectProxy Proxy
Implements | IExternalizable, IPropertyChangeNotifier
Subclasses | DataItem, ManagedObjectProxy

Language Version: | ActionScript 3.0

Product Version: | Flex 3

Runtime Versions: | Flash Player 9, AIR 1.1

This class provides the ability to track changes to an item managed by this proxy. Any number of objects can "listen" for changes on this object, by using the `addEventListener()` method.

Public Properties

| Property | Defined By
--- | --- | ---
|  | uid : String The unique identifier for this object. | ObjectProxy

Protected Properties

| Property | Defined By
--- | --- | ---
|  | dispatcher : EventDispatcher A reference to the EventDispatcher for this proxy. | ObjectProxy
|  | notifiers : Object A hashmap of property change notifiers that this proxy is listening for changes from; the key of the map is the property name. | ObjectProxy
|  | object : Object [read-only] The object being proxied. | ObjectProxy
|  | propertyList : Array Contains a list of all of the property names for the proxied object. | ObjectProxy
|  | proxyClass : Class Indicates what kind of proxy to create when proxying complex properties. | ObjectProxy
|  | type : QName The qualified type name associated with this object. | ObjectProxy

Public Methods

| Method | Defined By
--- | --- | ---
|  | ObjectProxy(item:Object = null, uid:String = null, proxyDepth:int = -1) Initializes this proxy with the specified object, id and proxy depth. | ObjectProxy
|  | addEventListener(type:String, listener:Function, useCapture:Boolean = false, priority:int = 0, useWeakReference:Boolean = false):void Registers an event listener object so that the listener receives notification of an event. | ObjectProxy
|  | dispatchEvent(event:Event):Boolean Dispatches an event into the event flow. | ObjectProxy
|  | hasEventListener(type:String):Boolean Checks whether there are any event listeners registered for a specific type of event. | ObjectProxy
|  | propertyChangeHandler(event:PropertyChangeEvent):void Called when a complex property is updated. | ObjectProxy
|  | readExternal(input:IDataInput):void Since Flex only uses ObjectProxy to wrap anonymous objects, the server flex.messaging.io.ObjectProxy instance serializes itself as a Map that will be returned as a plain ActionScript object. | ObjectProxy
|  | removeEventListener(type:String, listener:Function, useCapture:Boolean = false):void Removes an event listener. | ObjectProxy
|  | willTrigger(type:String):Boolean Checks whether an event listener is registered with this object or any of its ancestors for the specified event type. | ObjectProxy
|  | writeExternal(output:IDataOutput):void Since Flex only serializes the inner ActionScript object that it wraps, the server flex.messaging.io.ObjectProxy populates itself with this anonymous object's contents and appears to the user as a Map. | ObjectProxy

Protected Methods

| Method | Defined By
--- | --- | ---
|  | callProperty(name:*, ... rest):* [override] Returns the value of the proxied object's method with the specified name. | ObjectProxy
|  | deleteProperty(name:*):Boolean [override] Deletes the specified property on the proxied object and sends notification of the delete to the handler. | ObjectProxy
|  | getComplexProperty(name:*, value:*):* Provides a place for subclasses to override how a complex property that needs to be either proxied or daisy chained for event bubbling is managed. | ObjectProxy
|  | getProperty(name:*):* [override] Returns the specified property value of the proxied object. | ObjectProxy
|  | setProperty(name:*, value:*):void [override] Updates the specified property on the proxied object and sends notification of the update to the handler. | ObjectProxy
|  | setupPropertyList():void This method creates an array of all of the property names for the proxied object. | ObjectProxy

Property Detail

### dispatcher

property

`protected var dispatcher:EventDispatcher`

Language Version: | ActionScript 3.0

Product Version: | Flex 3

Runtime Versions: | Flash Player 9, AIR 1.1

A reference to the EventDispatcher for this proxy.

### notifiers

property

`protected var notifiers:Object`

Language Version: | ActionScript 3.0

Product Version: | Flex 3

Runtime Versions: | Flash Player 9, AIR 1.1

A hashmap of property change notifiers that this proxy is listening for changes from; the key of the map is the property name.

### object

property

`object:Object` [read-only]

Language Version: | ActionScript 3.0

Product Version: | Flex 3

Runtime Versions: | Flash Player 9, AIR 1.1

The object being proxied.

Implementation
`object_proxy function get object():Object`

### propertyList

property

`protected var propertyList:Array`

Language Version: | ActionScript 3.0

Product Version: | Flex 3

Runtime Versions: | Flash Player 9, AIR 1.1

Contains a list of all of the property names for the proxied object. Descendants need to fill this list by overriding the `setupPropertyList()` method.

### proxyClass

property

`protected var proxyClass:Class`

Language Version: | ActionScript 3.0

Product Version: | Flex 3

Runtime Versions: | Flash Player 9, AIR 1.1

Indicates what kind of proxy to create when proxying complex properties. Subclasses should assign this value appropriately.

### type

property

`type:QName`

Language Version: | ActionScript 3.0

Product Version: | Flex 3

Runtime Versions: | Flash Player 9, AIR 1.1

The qualified type name associated with this object.

Implementation
`object_proxy function get type():QName`
`object_proxy function set type(value:QName):void`

### uid

property

`uid:String`

Language Version: | ActionScript 3.0

Product Version: | Flex 3

Runtime Versions: | Flash Player 9, AIR 1.1

The unique identifier for this object.

Implementation
`public function get uid():String`
`public function set uid(value:String):void`
Constructor Detail

### ObjectProxy

()
Constructor

`public function ObjectProxy(item:Object = null, uid:String = null, proxyDepth:int = -1)`

Language Version: | ActionScript 3.0

Product Version: | Flex 3

Runtime Versions: | Flash Player 9, AIR 1.1

Initializes this proxy with the specified object, id and proxy depth.

Parameters

| `item:Object` (default = `null`)`` — Object to proxy. If no item is specified, an anonymous object will be constructed and assigned.
| `uid:String` (default = `null`)`` — String containing the unique id for this object instance. Required for IPropertyChangeNotifier compliance as every object must provide a unique way of identifying it. If no value is specified, a random id will be assigned.
| `proxyDepth:int` (default = `-1`)`` — An integer indicating how many levels in a complex object graph should have a proxy created during property access. The default is -1, meaning "proxy to infinite depth".

Example
How to use this example

          import mx.events.PropertyChangeEvent;
          import mx.utils.ObjectUtil;
          import mx.utils.ObjectProxy;
          import mx.utils.StringUtil;

          var a:Object = { name: "Tyler", age: 5, ssnum: "555-55-5555" };
          var p:ObjectProxy = new ObjectProxy(a);
          p.addEventListener(PropertyChangeEvent.PROPERTY_CHANGE, updateHandler);
          p.name = "Jacey";
          p.age = 2;
          delete p.ssnum;

          // handler function
          function updateHandler(event:PropertyChangeEvent):void
          {
              trace(StringUtil.substitute("updateHandler('{0}', {1}, {2}, {3}, '{4}')",
                                             event.kind,
                                             event.property,
                                             event.oldValue,
                                             event.newValue,
                                             event.target.uid));
          }

          // trace output
          updateHandler('opUpdate', name, Jacey, '698AF8CB-B3D9-21A3-1AFFDGHT89075CD2')
          updateHandler('opUpdate', age, 2, '698AF8CB-B3D9-21A3-1AFFDGHT89075CD2')
          updateHandler('opDelete', ssnum, null, '698AF8CB-B3D9-21A3-1AFFDGHT89075CD2')

Method Detail

### addEventListener

()
method

`public function addEventListener(type:String, listener:Function, useCapture:Boolean = false, priority:int = 0, useWeakReference:Boolean = false):void`

Language Version: | ActionScript 3.0

Product Version: | Flex 3

Runtime Versions: | Flash Player 9, AIR 1.1

Registers an event listener object so that the listener receives notification of an event. For more information, including descriptions of the parameters see `addEventListener()` in the flash.events.EventDispatcher class.

Parameters

| `type:String` — The type of event.
| `listener:Function` — The listener function that processes the event. This function must accept an Event object as its only parameter and must return nothing.
| `useCapture:Boolean` (default = `false`)`` — Determines whether the listener works in the capture phase or the target and bubbling phases. If `useCapture` is set to `true`, the listener processes the event only during the capture phase and not in the target or bubbling phase. If `useCapture` is `false`, the listener processes the event only during the target or bubbling phase. To listen for the event in all three phases, call `addEventListener` twice, once with `useCapture` set to `true`, then again with `useCapture` set to `false`.
| `priority:int` (default = `0`)`` — The priority level of the event listener.
| `useWeakReference:Boolean` (default = `false`)`` — Determines whether the reference to the listener is strong or weak. A strong reference (the default) prevents your listener from being garbage-collected. A weak reference does not.

Related API Elements

flash.events.EventDispatcher.addEventListener()

### callProperty

()
method

`override flash_proxy function callProperty(name:*, ... rest):*`

Language Version: | ActionScript 3.0

Product Version: | Flex 3

Runtime Versions: | Flash Player 9, AIR 1.1

Returns the value of the proxied object's method with the specified name.

Parameters

| `name:*` — The name of the method being invoked.
| `... rest` — An array specifying the arguments to the called method.

Returns

| `*` — The return value of the called method.

### deleteProperty

()
method

`override flash_proxy function deleteProperty(name:*):Boolean`

Language Version: | ActionScript 3.0

Product Version: | Flex 3

Runtime Versions: | Flash Player 9, AIR 1.1

Deletes the specified property on the proxied object and sends notification of the delete to the handler.

Parameters

| `name:*` — Typically a string containing the name of the property, or possibly a QName where the property name is found by inspecting the `localName` property.

Returns

| `Boolean` — A Boolean indicating if the property was deleted.

### dispatchEvent

()
method

`public function dispatchEvent(event:Event):Boolean`

Language Version: | ActionScript 3.0

Product Version: | Flex 3

Runtime Versions: | Flash Player 9, AIR 1.1

Dispatches an event into the event flow. For more information, see the flash.events.EventDispatcher class.

Parameters

| `event:Event` — The Event object that is dispatched into the event flow. If the event is being redispatched, a clone of the event is created automatically. After an event is dispatched, its target property cannot be changed, so you must create a new copy of the event for redispatching to work.

Returns

| `Boolean` — Returns `true` if the event was successfully dispatched. A value of `false` indicates failure or that `preventDefault()` was called on the event.

Related API Elements

flash.events.EventDispatcher.dispatchEvent()

### getComplexProperty

()
method

`object_proxy function getComplexProperty(name:*, value:*):*`

Language Version: | ActionScript 3.0

Product Version: | Flex 3

Runtime Versions: | Flash Player 9, AIR 1.1

Provides a place for subclasses to override how a complex property that needs to be either proxied or daisy chained for event bubbling is managed.

Parameters

| `name:*` — Typically a string containing the name of the property, or possibly a QName where the property name is found by inspecting the `localName` property.
| `value:*` — The property value.

Returns

| `*` — The property value or an instance of `ObjectProxy`.

### getProperty

()
method

`override flash_proxy function getProperty(name:*):*`

Language Version: | ActionScript 3.0

Product Version: | Flex 3

Runtime Versions: | Flash Player 9, AIR 1.1

Returns the specified property value of the proxied object.

Parameters

| `name:*` — Typically a string containing the name of the property, or possibly a QName where the property name is found by inspecting the `localName` property.

Returns

| `*` — The value of the property. In some instances this value may be an instance of `ObjectProxy`.

### hasEventListener

()
method

`public function hasEventListener(type:String):Boolean`

Language Version: | ActionScript 3.0

Product Version: | Flex 3

Runtime Versions: | Flash Player 9, AIR 1.1

Checks whether there are any event listeners registered for a specific type of event. This allows you to determine where an object has altered handling of an event type in the event flow hierarchy. For more information, see the flash.events.EventDispatcher class.

Parameters

| `type:String` — The type of event

Returns

| `Boolean` — Returns `true` if a listener of the specified type is registered; `false` otherwise.

Related API Elements

flash.events.EventDispatcher.hasEventListener()

### propertyChangeHandler

()
method

`public function propertyChangeHandler(event:PropertyChangeEvent):void`

Language Version: | ActionScript 3.0

Product Version: | Flex 3

Runtime Versions: | Flash Player 9, AIR 1.1

Called when a complex property is updated.

Parameters

| `event:PropertyChangeEvent` — An event object that has changed.

### readExternal

()
method

`public function readExternal(input:IDataInput):void`

Language Version: | ActionScript 3.0

Product Version: | Flex 3

Runtime Versions: | Flash Player 9, AIR 1.1

Since Flex only uses ObjectProxy to wrap anonymous objects, the server flex.messaging.io.ObjectProxy instance serializes itself as a Map that will be returned as a plain ActionScript object. You can then set the object_proxy object property to this value.

Parameters

| `input:IDataInput` — The source object from which the ObjectProxy is deserialized.

### removeEventListener

()
method

`public function removeEventListener(type:String, listener:Function, useCapture:Boolean = false):void`

Language Version: | ActionScript 3.0

Product Version: | Flex 3

Runtime Versions: | Flash Player 9, AIR 1.1

Removes an event listener. If there is no matching listener registered with the EventDispatcher object, a call to this method has no effect. For more information, see the flash.events.EventDispatcher class.

Parameters

| `type:String` — The type of event.
| `listener:Function` — The listener object to remove.
| `useCapture:Boolean` (default = `false`)`` — Specifies whether the listener was registered for the capture phase or the target and bubbling phases. If the listener was registered for both the capture phase and the target and bubbling phases, two calls to `removeEventListener()` are required to remove both, one call with `useCapture` set to `true`, and another call with `useCapture` set to `false`.

Related API Elements

flash.events.EventDispatcher.removeEventListener()

### setProperty

()
method

`override flash_proxy function setProperty(name:*, value:*):void`

Language Version: | ActionScript 3.0

Product Version: | Flex 3

Runtime Versions: | Flash Player 9, AIR 1.1

Updates the specified property on the proxied object and sends notification of the update to the handler.

Parameters

| `name:*` — Object containing the name of the property that should be updated on the proxied object.
| `value:*` — Value that should be set on the proxied object.

### setupPropertyList

()
method

`protected function setupPropertyList():void`

Language Version: | ActionScript 3.0

Product Version: | Flex 3

Runtime Versions: | Flash Player 9, AIR 1.1

This method creates an array of all of the property names for the proxied object. Descendants must override this method if they wish to add more properties to this list. Be sure to call `super.setupPropertyList` before making any changes to the `propertyList` property.

### willTrigger

()
method

`public function willTrigger(type:String):Boolean`

Language Version: | ActionScript 3.0

Product Version: | Flex 3

Runtime Versions: | Flash Player 9, AIR 1.1

Checks whether an event listener is registered with this object or any of its ancestors for the specified event type. This method returns `true` if an event listener is triggered during any phase of the event flow when an event of the specified type is dispatched to this object or any of its descendants. For more information, see the flash.events.EventDispatcher class.

Parameters

| `type:String` — The type of event.

Returns

| `Boolean` — Returns `true` if a listener of the specified type will be triggered; `false` otherwise.

Related API Elements

flash.events.EventDispatcher.willTrigger()

### writeExternal

()
method

`public function writeExternal(output:IDataOutput):void`

Language Version: | ActionScript 3.0

Product Version: | Flex 3

Runtime Versions: | Flash Player 9, AIR 1.1

Since Flex only serializes the inner ActionScript object that it wraps, the server flex.messaging.io.ObjectProxy populates itself with this anonymous object's contents and appears to the user as a Map.

Parameters

| `output:IDataOutput` — The source object from which the ObjectProxy is deserialized.

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Mon Apr 10 2017, 12:28 PM -07:00