This topic describes developing mediations, from coding through to deployment
Programming mediations involves two types of task that draw on different technical skills: programming and integration. Typically, Java programmers will design and code mediations as components called handlers. Integration involves aggregating the mediation handlers using handler lists, then assembling them into a deployable unit to deploy and install them.
Programming. The basic programming task is to create a mediation handler. This is a wrapper for the mediation code that operates on the message. You can create the handler code using information in Writing a mediation handler. Then you will need to add the function mediation code, see Adding mediation function to handler code. There are three different APIs you will use to work with messages: the SIMessage and SIMessageContext APIs allow you to manipulate the contents of the message, and the SIMediationSession API gives access to the service integration bus so you can send and retrieve messages. See Service integration programming resources for an overview of the APIs, and see SIMessageContext for reference information and access to the generated API information.
Integration. Mediations can be "pipelined" to create a more powerful set of operations to be performed on a message. At runtime, each handler in the list is invoked in sequence. Each time a handler returns a value of True, the same message context is passed to the next handler. If a handler returns false, then the context is not passed to any more handlers, which will result in the message being discarded and it will not be delivered to the destination. You use the Application Server Toolkit deployment wizard to create handler lists (which may be simply a list of one handler) before deploying the handler list as an Enterprise Archive (EAR file).