Adding mediation primitives to the flow

This topic describes how to add mediation primitives to the flow in the Mediation Flow editor.

The end nodes of the request and response flows are created based on operations that are defined in the Operation Connection section of the editor. You create a flow by adding mediation primitives between these nodes. Add the primitives from left to right in the sequence that you want them to be invoked in the flow, wire them together, and set the properties of each primitives to determine how the primitive will process the message. The mediation primitives are available in the palette on the left of the request or response flow, as shown below:

Mediation primitives in the palette

Select a primitive from the palette and drop it onto the canvas.

For ease of access, primitives in the palette are contained groups. Click on the arrow beside the primitive icon to view and select a primitive from the group, as shown below:
Expanded group in the palette
These are the primitives in the palette:

  • The Event Emitter primitive Event Emitter primitive in the palette emits a common base event at a point significant in the mediation flow.
  • The Message Element Setter primitive sets, copies, or deletes the content of message headers or bodies.Message Element Setter primitive in the palette
  • The Endpoint Lookup mediation primitive queries the WebSphere® Service Registry and Repository and retrieves service endpoints, which it places in the message context. The retrieved endpoints can then be used to dynamically invoke a service. Endpoint Lookup mediation primitive
  • The Message Logger primitive Message Logger primitive in the palette logs messages to a database.
  • The Message Filter primitive Message Filter primitive in the palette conditionally routes messages based on the results of pattern evaluation. A pattern is evaluated against the message, and if the result is true, the message is propagated to a terminal associated with the pattern.
  • The Database Lookup primitive Database Lookup primitive in the palette enriches the message using data retrieved from a database.
  • The Stop mediation primitive Stop primitive in the palette silently stops the execution of the current path in the flow. This is an expected termination , and is not caused by an execution failure in the primitive.
  • The Fail mediation primitive Fail primitive in the palette stops the execution of the flow and throws an exception when there is a known execution failure in the primitive. You can define your own exceptions for the Fail primitive.
  • The Custom Mediation primitive Custom Mediation primitive in the palette allows you to implement your own mediation logic using Java™ code, or to call an import in the same mediation module.
  • The XSL Transformation primitive XSL Transformation primitive in the palette transforms message formats between source and target operations, or changes the content of a message. The primitive uses an XSL style sheet to map between the source and target message types.

In addition to these primitives supplied with WebSphere Integration Developer, you can create your own mediation primitives and contribute them to the mediation flow editor palette. You can then use these primitives in your mediation flow. For more information, see topic "Contributing your own mediation primitive plug-in" in the related information.

After you have added your mediation primitives, wire your flow, and set the properties of the mediation primitives.
Related tasks
Defining source and target operations
Wiring a mediation flow
Building XPath expressions

Related information

Setting properties in mediation flows

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