Chapter 7. Application and system design guidelines 223
Augmenting messages by adding data from a data source.
Distributing messages to multiple target destinations.
A mediation is associated with a destination on the bus to create a mediated
destination. A mediated destination has two parts:
post-mediated. Applications send messages to the pre-mediated part, and
receive them from the post-mediated part. A mediation receives messages from
the pre-mediated part, transforms the messages in some way, and places one or
more messages on the post-mediated part. In this way, the mediation controls
the progress of messages to their intended target destination.
A mediation can operate within a global unit of work to ensure transactional
integrity. Several mediations can operate at the same time to improve the
throughput of messages at a destination.
The behavior of a mediation is defined by a mediation handler list. Mediation
handler lists contain one or more mediation handlers.
A mediation handler is a Java program that performs the function of a mediation,
and can be deployed in a mediation handler list. The mediation handler class
implements the following interface:
A mediation handler can have properties that control its behavior.
A mediation handler is packaged for deployment with a supplied EJB. At
deployment, you can set properties to control the behavior of the mediation at
run-time, and specify membership of one or more mediation handler lists. You
deploy a mediation handler as an EAR file and install it into WebSphere
Mediation handler lists
A mediation handler list is a collection of mediation handlers that are invoked in
A mediation handler list is a simple pipeline of mediation handlers. The same
parameters are passed from one mediation handler to the next mediation
handler in the list.