Whether the service is currently considered "available."

The initial value is false until either a status check sets the property to true or the 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.

The time of the last status update.

The interval, in milliseconds, for polling the server.

If zero, the server is not polled periodically, but only immediately after start() is called and when the network status changes.

The default value is 0.

Whether the monitor has been started.

Creates a ServiceMonitor object.

The class can be specialized in JavaScript (from HTML application content), as described in the description of the makeJavascriptSubclass() method.

After creating a ServiceMonitor object (or a subclass object), 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 ServiceMonitor object. Otherwise, the runtime deletes the object and monitoring ends.

Check the status of the service.

A subclass override method for checking the status of the service.

Typically, this method will initiate a network operation whose completion or failure will result in setting the available property.

JavaScript code can specialise this method by defining a checkStatus() method in the "specializer" object.

Adds public ServiceMonitor methods to a JavaScript constructor function's prototype.

Adds functions to the JavaScript constructor function's prototype that forward public ServiceMonitor functions to the ServiceMonitor. This approximates a normal JavaScript subclass of the ActionScript base class.

A JavaScript class specializing a ServiceMonitor would look like this:

  // JavaScript Constructor function
  function MyHTTPMonitor(url, method)
  {
      // "that" variable makes "this" available in closures below
      var that = this;
      // Required initialization of the service monitor, returns the actual ServiceMonitor object.
      this.monitor = this.initServiceMonitor();
      // Initializes URLStream and event handlers.
      this._urlStream = new air.URLStream();
      this._urlRequest = new air.URLRequest(url);
      if (method)
      {
          this._urlRequest.method = method;
      }
      else
      {
          this._urlRequest.method = "GET";
      }
      function onStatus(event) {
          that.monitor.available = Number(event.status) == 200;
          that._urlStream.close();
      }
      function onError(event)
      {
          that.monitor.available = false;
          that._urlStream.close();
      }
      this._urlStream.addEventListener(air.HTTPStatusEvent.HTTP_RESPONSE_STATUS, onStatus);
      this._urlStream.addEventListener(air.SecurityErrorEvent.SECURITY_ERROR, onError);
      this._urlStream.addEventListener(air.IOErrorEvent.IO_ERROR, onError);
  }
    // Augment JavaScript prototype with public methods from ServiceMonitor
  air.ServiceMonitor.makeJavascriptSubclass(MyHTTPMonitor);
    // Implement specializer functions, just as you would when subclassing a JavaScript class
  MyHTTPMonitor.prototype.checkStatus = function()
  {
      air.trace('OVERRIDDEN checkStatus!', this);
      this._urlStream.load(this._urlRequest);
  }
  

To use the JavaScript class:

  var httpMon = new MyHTTPMonitor('http://www.adobe.com')
  

Be sure to load the AIRAliases.js and ServiceMonitor.swf files with script tags.

Parameters

Start the service monitor.

Stop monitoring the service.

Indicates that the service status has changed.

The value of the "code" property will be either "Service.available" or "Service.unavailable", but best practice is to check the value of the ServiceMonitor.available property.