Agile Enterprise Application Development with Flex

The ReliableClientMessage Class

The ActionScript class that knows how to send reliable messages and its Java counterpart are presented in Examples 5-24 and 5-25. Every outgoing ReliableClientMessage will have a unique sequential header, seqNo.

Example 5-24. ReliableClientMessage.as

package com.farata.messaging.messages{
   import mx.messaging.messages.AsyncMessage;

   [RemoteClass(alias="com.farata.messaging.messages.ReliableClientMessage")]
   public class ReliableClientMessage extends AsyncMessage   {

      static public var sequenceNo : int = 0;

      public function ReliableClientMessage(
         body:Object=null, headers:Object=null
      ) {
         if (!headers) {
            headers = [];
         }
         headers["seqNo"] = sequenceNo++;
         super(body, headers);
      }
   }
}

Example 5-25. ReliableClientMessage.java

package com.farata.messaging.messages;

import flex.messaging.messages.AsyncMessage;

public class ReliableClientMessage extends AsyncMessage {
}

Note

The only reason for creating a subclass of AsyncMessage.java is to have a way to separate regular AsyncMessage objects that don’t require special processing from the reliable ones.

Figure 5-10. Design of the No Client Message Left Behind policy