Enterprise messaging is at the core of an ESB architecture. In this chapter we will explore Message Oriented Middleware (MOM) and what it contributes to an enterprise integration strategy. A MOM is a key part of the ESB architecture, as it provides the underpinnings of the network of virtual channels that an ESB uses to route messages throughout an extended enterprise and beyond.
Message Oriented Middleware is a concept that involves the passing of data between applications using a communication channel that carries self-contained units of information (messages). In a MOM-based communication environment, messages are usually sent and received asynchronously. Using message-based communications, applications are abstractly decoupled; senders and receivers are never aware of each other. Instead, they send and receive messages to and from the messaging system. It is the responsibility of the messaging system (MOM) to get the messages to their intended destinations.
In a messaging system, an application uses an API to communicate through a messaging client that is provided by the MOM vendor. The messaging client sends and receives messages through a messaging system, as illustrated in Figure 5-1.
The messaging system is responsible for ...