Synchronous Message Processing

As mentioned earlier, one way for an application to receive messages is to have the AMPS Java client return a MessageStream object that can be used to iterate over the results of the command.

The MessageStream object makes copies of the incoming messages. When there is no message available, the MessageStream will block.

A MessageStream will only remain active while the client that produced it is connected. If the client disconnects, the MessageStream will continue to provide any messages that have not yet been consumed, then throw an exception.

The advantages of using a MessageStream that it provides a simple processing model, that receiving messages from a MessageStream does not block the client receive thread (see Understanding Threading ) and that a copy of the message is automatically made for the application.

In return for these advantages, a MessageStream has higher overhead than Asynchronous Message Processing, it will not be resumed if the client disconnects, and, by default, it will use as much memory as necessary to hold messages coming from the AMPS server.