Mediation modules

Mediation modules are Service Component Architecture (SCA) modules that can change the format, content or target of service requests.

Mediation modules operate on messages that are in flight between service requesters and service providers. They allow you to route messages to different service providers. They also let you transform messages: you can amend message content or form. In addition, mediation modules can provide functions such as message logging, and error processing that is tailored to your requirements.

Components of mediation modules

Among the items that mediation modules contain are the following:
  • Imports.
    • Imports define interactions between Service Component Architecture (SCA) modules and service providers.
    • Imports allow SCA modules to call external services as if they were local.
    • Mediation module imports can be viewed from WebSphere Process Server and if the import binding is an SCA binding, then it can be modified to point to another SCA module.
  • Exports.
    • Exports define interactions between Service Component Architecture (SCA) modules and service requesters.
    • Exports allow an SCA module to offer a service. Exports define the external interfaces (access points) of an SCA module.
    • Mediation module exports can be viewed from WebSphere Process Server.
  • Service Component Architecture (SCA) components.
    • SCA components, or service components, are SCA building blocks. You build SCA modules such as mediation modules, using SCA components. You can create and customize SCA modules and components graphically, using WebSphere Integration Developer.
    • Typically, mediation modules contain a specific type of SCA component called a mediation flow component. A mediation module can contain, at most, one mediation flow component.
    • A mediation flow component can contain one mediation primitive, a number of mediation primitives or no mediation primitives. WebSphere Process Server supports a supplied set of mediation primitives that provide functionality for message routing and transformation. One of the mediation primitives that WebSphere Process Server supports allows you to invoke custom logic.
    • A mediation module does not have to contain a mediation flow component. The purpose of a mediation module that does not contain a mediation flow component is to transform service requests from one protocol to another. For example, a service request might be made using SOAP/JMS but need transforming to SOAP/HTTP before sending on.
    Note: You can view mediation modules from WebSphere Process Server. You can also make limited changes to mediation modules from WebSphere Process Server. However, you cannot view or change SCA components or mediation primitives from WebSphere Process Server. Use WebSphere Integration Developer to customize SCA components and mediation primitives.
    Figure 1. Simplified example of a mediation module. The mediation module contains one mediation flow component. The mediation flow component contains mediation primitives.
    The mediation module contains one mediation flow component. The mediation flow component contains mediation primitives.

Deploying mediation modules

Mediation modules are created using WebSphere Integration Developer, and deployed to WebSphere Process Server inside an enterprise archive (EAR) file. Therefore, a mediation module is deployed to WebSphere Process Server in the same way you deploy enterprise applications.

WebSphere Integration Developer packages mediation modules inside Java archive (JAR) files, and the JAR files are then stored inside EAR files.

Logically, mediation modules can be thought of as one entity. In reality, SCA modules are defined by a number of XML files stored in one JAR file.

  • EAR file.
    • Contains JAR file.
      • Contains Mediation module.
        Figure 2. Simplified example of an EAR file containing a mediation module. The EAR file contains JAR files. The utility JAR file contains a mediation module.
        The EAR file contains JARs. The utility JAR file contains a mediation module.

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Last updated: Tue Feb 21 16:59:46 2006

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