air.net.URLMonitor - Adobe® Flex® 4 Language Reference (Flex 4)

Package	air.net
Class	public class URLMonitor
Inheritance	URLMonitor ServiceMonitor EventDispatcher Object

Runtime Versions:

AIR 1.0

The URLMonitor class monitors availablity of an HTTP- or HTTPS-based service.

This class is included in the ServiceMonitor.swc file. Adobe^® Flash^® Builder™ loads this class automatically when you create a project for Adobe^® AIR^®. The Adobe^® Flex^® SDK also includes this servicemonitor.swc file, which you should include when compiling the application if you are using the Flex SDK.

In Adobe^® Flash^® CS3 Professional, this class is included in the ServiceMonitorShim.swc file. To use classes in the air.net package , you must first drag the ServiceMonitorShim component from the Components panel to the Library and then add the following import statement to your ActionScript 3.0 code:

import air.net.*;

To use air.net package in Adobe^® Flash^® CS4 Professional:

Select the File > Publish Settings command.
In the Flash panel, click the Settings button for ActionScript 3.0. Select Library Path.
Click the Browse to SWC File button. Browse to Adobe Flash CS4/AIK1.1/frameworks/libs/air/servicemoniter.swc file in the Adobe Flash CS4 installation folder.
Click the OK button.
Add the following import statement to your ActionScript 3.0 code: import air.net.*;

Public Properties

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	Property		Defined By
		acceptableStatusCodes : Array The numeric status codes representing a successful result.	URLMonitor
		available : Boolean Whether the service is currently considered "available." The initial value is false until either a status check sets the property to true or the property is initialized to true explicitly. Typically, this property is set by the checkStatus() implementation in a subclass or specializer, but if the application has independent information about a service's availability (for example, a request just succeeded or failed), the property can be set explicitly.	ServiceMonitor
		constructor : Object A reference to the class object or constructor function for a given object instance.	Object
		lastStatusUpdate : Date [read-only] The time of the last status update.	ServiceMonitor
		pollInterval : Number The interval, in milliseconds, for polling the server.	ServiceMonitor
		prototype : Object [static] A reference to the prototype object of a class or function object.	Object
		running : Boolean [read-only] Whether the monitor has been started.	ServiceMonitor
		urlRequest : URLRequest [read-only] The URLRequest object representing the probe request.	URLMonitor

Public Methods

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	Method		Defined By
		URLMonitor(urlRequest:URLRequest, acceptableStatusCodes:Array = null) Creates a URLMonitor Object for a specified HTTP- or HTTPS-based service.	URLMonitor
		addEventListener(type:String, listener:Function, useCapture:Boolean = false, priority:int = 0, useWeakReference:Boolean = false):void Registers an event listener object with an EventDispatcher object so that the listener receives notification of an event.	EventDispatcher
		dispatchEvent(event:Event):Boolean Dispatches an event into the event flow.	EventDispatcher
		hasEventListener(type:String):Boolean Checks whether the EventDispatcher object has any listeners registered for a specific type of event.	EventDispatcher
		hasOwnProperty(name:String):Boolean Indicates whether an object has a specified property defined.	Object
		isPrototypeOf(theClass:Object):Boolean Indicates whether an instance of the Object class is in the prototype chain of the object specified as the parameter.	Object
		makeJavascriptSubclass(constructorFunction:Object):void [static] Adds public ServiceMonitor methods to a JavaScript constructor function's prototype.	ServiceMonitor
		propertyIsEnumerable(name:String):Boolean Indicates whether the specified property exists and is enumerable.	Object
		removeEventListener(type:String, listener:Function, useCapture:Boolean = false):void Removes a listener from the EventDispatcher object.	EventDispatcher
		setPropertyIsEnumerable(name:String, isEnum:Boolean = true):void Sets the availability of a dynamic property for loop operations.	Object
		start():void Starts the service monitor.	ServiceMonitor
		stop():void Stops monitoring the service.	ServiceMonitor
		toLocaleString():String Returns the string representation of this object, formatted according to locale-specific conventions.	Object
		toString():String [override] Returns the string representation of the specified object.	URLMonitor
		valueOf():Object Returns the primitive value of the specified object.	Object
		willTrigger(type:String):Boolean Checks whether an event listener is registered with this EventDispatcher object or any of its ancestors for the specified event type.	EventDispatcher

Protected Methods

	Method		Defined By
		checkStatus():void [override] Attempts to load content from a URL in the background, to check for a returned HTTP status code.	URLMonitor

Events

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	Summary	Defined By
activate	[broadcast event] Dispatched when the Flash Player or AIR application gains operating system focus and becomes active.	EventDispatcher
deactivate	[broadcast event] Dispatched when the Flash Player or AIR application operating loses system focus and is becoming inactive.	EventDispatcher
status	Indicates that the service status has changed.	ServiceMonitor

Property Detail

acceptableStatusCodes

property

acceptableStatusCodes:Array

Runtime Versions:

AIR 1.0

The numeric status codes representing a successful result.

Implementation
public function get acceptableStatusCodes():Array
public function set acceptableStatusCodes(value:Array):void

urlRequest

property

urlRequest:URLRequest [read-only]

Runtime Versions:

AIR 1.0

The URLRequest object representing the probe request.

Implementation
public function get urlRequest():URLRequest

Constructor Detail

URLMonitor

()

Constructor

public function URLMonitor(urlRequest:URLRequest, acceptableStatusCodes:Array = null)

Runtime Versions:

AIR 1.0

Creates a URLMonitor Object for a specified HTTP- or HTTPS-based service.

After creating a URLMonitor, the caller should call the start() method to begin monitoring the status of the service.

As with the Timer object, the caller should maintain a reference to the URLMonitor object. Otherwise the runtime could delete the object, thereby ending the monitoring.

A URLRequest parameter specifies the probe request for polling the server. Typically, the request method will be either "GET" or "HEAD".

Parameters

urlRequest:URLRequest — The URLRequest object representing a probe request for polling the server.

acceptableStatusCodes:Array (default = null) — An array of numeric status codes listing the codes that represent a successful result.

If you do not specify a value for the acceptableStatusCodes property, the following status codes will be recognized as successful responses:

200 (OK)
202 (Accepted)
204 (No content
205 (Reset content)
206 (Partial content, in response to request with a Range header)

Method Detail

checkStatus

()

method

override protected function checkStatus():void

Runtime Versions:

AIR 1.0

Attempts to load content from a URL in the background, to check for a returned HTTP status code.

If it receives a status code that is listed in the acceptableStatusCodes property, the available property will be set to true. If it receives a status code that is not in the acceptableStatusCodes list, or if there is a security error or I/O error, the available property will be set to false.

toString

()

method

override public function toString():String

Runtime Versions:

AIR 1.0

Returns the string representation of the specified object.

Note: Methods of the Object class are dynamically created on Object's prototype. To redefine this method in a subclass of Object, do not use the override keyword. For example, a subclass of Object implements function toString():String instead of using an override of the base class.

Returns

String — A string representation of the object.