Understanding How the Flex Message Service Works

The FMS provides both a client API and a server-side service for creating messaging applications. The core purpose of these services is to enable messages to be asynchronously exchanged between Flex clients and the Flex server. There are a number of different places these messages could originate, such as the following:

• Java Message Service (JMS)

• ColdFusion event gateways

• Other Flex clients using the <mx:Producer> tag (not covered in this book)

There are a few important terms you should understand when working with FMS:

Message A piece of data sent from a message producer through the messaging service to a consumer. A message consists of a header that describes the message and a body that contains the data for the message.

Consumer An application that makes use of messages. By the end of this lesson, your Dashboard application will be a consumer.

Producer The sender of a message.

Destination An identifier for a place to which a producer sends a message. The FMS will route the message appropriately, based on its destination. This architecture makes it possible for the producers and consumers to be entirely decoupled, knowing nothing about each other.

Channel A gateway to a message destination. Producers use channels to connect to the destination within FDS, and FDS uses channels to connect to the listening consumers.

Adapter Elements that translate messages between the FDS and external messaging services. FDS ships with adapters for JMS, ColdFusion Gateways, and the ActionScript adapter, which is used to send messages to the Flash clients.