Mediation handlers and mediation handler lists

Mediations are specified as a simple sequential list of mediation handlers. The mediation handler list is assembled and deployed into a Enterprise Applications Archive and installed into WebSphere® Application Server, where it is ready to perform some specific message processing at a destination. A mediation handler is the Java™ class that processes the messages in some way.

The mediation handler performs its message processing at runtime without changing the fundamental properties of the messages, including the message ID. Examples of message processing performed by a mediation handler include the following:

The mediation handler class implements the Java interface com.ibm.websphere.sib.mediation.handler.MediationHandler. The mediations assembler (or developer) assembles the mediation handler class into a file called an Enterprise Applications Archive (EAR). It is then deployed in a mediation handler list using one of two tools; the WebSphere Application Assembly Toolkit or Rational® Applications Development.

When you assign a mediation handler to a mediation handler list, you assign a sequence number to the mediation handler. You can assign one or more mediation handlers to the mediation handler list to define a set of operations to apply to each message. The sequence number is used to determine the specific sequence in which the mediations in the mediation handler lists are invoked. An administrator configures and creates a mediation in the administrative console, attaching it to a destination. The administrator can specify a name for the mediation handler list, although by default it has the same as the mediation handle.
Figure 1. Mediation handler lists

In most cases, you will assign only one mediation handler to a mediation handler list. The tooling used to deploy the mediation handler into an EAR provides a basic configuration option for automatically adding the mediation handler to its own mediation handler list.

The behavior of a mediation handler can be controlled by setting properties at various stages of mediation development. You can set these properties when you write the Java class, assemble and deploy the mediation handler, or at runtime when the mediation is created and installed.




Related concepts
Mediations
Related tasks
Installing a mediation application into WebSphere Application Server
Configuring mediations
Programming mediations
Securing mediations
Configuring an alternative mediation identity for a mediation handler
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Last updated: Aug 29, 2010 6:22:59 PM CDT
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