IBM BPM, V8.0.1, All platforms > Authoring services in Integration Designer > Services and service-related functions > Access external services with messaging systems > WebSphere MQ (WMQ)
WebSphere MQ programming model
The WebSphere MQ programming model is discussed in this section.
Message queuing (MQ) is a way to have application-to-application communication in an asynchronous manner instead of the tightly-coupled synchronous manner. Applications write and retrieve messages (or data) using queues without requiring a direct connection. Using queues means that the sending and receiving applications do not need to be running concurrently. Simply put, message queues allow applications to be loosely coupled, a goal in service oriented applications. IBM WebSphere MQ products let applications send and receive messages across a network of operating systems, subsystems and protocols making WebSphere MQ products widely used in the computer industry. WebSphere MQ products are particularly of importance to developers building applications which require a reliable means of delivering data between applications.
Two different application programming interfaces, Message Queueing Interface (MQI) and MQ Java™ Message Service (JMS), are supported. MQ JMS is MQ's support for the JMS API. MQ JMS is discussed in the WebSphere MQ JMS programming model section. One important feature of MQI is that it has few commands, this ease-of-use combined with the widespread use of WebSphere MQ products means that MQI has become a de facto standard for many developers as the message queuing interface. In the diagram below the WMQ client application interacts with the WMQ server through the MQI Application Programming Interface (API).
The diagram shows the basic elements of how a service component architecture (SCA) application developed in IBM Integration Designer interacts with a WebSphere MQ application. The SCA application is running on a server. It uses the Java Naming and Directory Interface (JNDI) to retrieve configuration information when it is invoked. Both the MQ queue manager and the MQ queues have been registered in the JNDI directory. They can be registered in JNDI automatically.
The MQ bindings that allow the SCA application to interact with the WMQ client application through the WMQ server are either import bindings or export bindings. An import allows the SCA application to initiate the sending and receiving (in the case of a request-response operation) of messages to the WMQ client. An export is the reverse. The WMQ client application initiates the sending and receiving (in the case of a request-response operation) of messages to the SCA application.
To enable this communication, the SCA import or export must have the host name of the WMQ server, its port number, its send and receive destination queues (for one-way communication, only one queue destination is needed), and its server channel.
