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.
You can change certain aspects of mediation modules dynamically,
from the WebSphere Process Server administrative
console, without having to redeploy the module.
Components of mediation modules
Among the items
that
mediation modules contain
are the following:
- Imports
- Imports define interactions between 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 a Web service or SCA binding then it can be modified.
- Exports
- Exports define interactions between 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.
- 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.
In addition, you can customize some of the properties of SCA modules dynamically,
from WebSphere Process Server administrative
console, without having to redeploy the module.
- Typically, mediation modules contain
a specific type of SCA component called a mediation flow component. Mediation
flow components define mediation flows. 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 certain changes to mediation modules from WebSphere Process Server. However,
you cannot view or change the SCA components from inside a WebSphere Process Server module.
Use WebSphere Integration Developer to customize SCA
components.
Figure 1. Simplified example of a mediation module.
The mediation module contains one mediation flow component. The mediation
flow component contains mediation primitives.
- Properties
Deploying mediation modules
Mediation modules are
created using WebSphere Integration Developer,
and are generally deployed to WebSphere Process Server inside
an EAR (enterprise archive) file.
You can change the value of promoted
properties at deployment time.
You can export a mediation module from WebSphere Integration Developer, and cause WebSphere Integration Developer to
package the mediation module inside
a JAR (Java archive) file, and the JAR file inside an EAR file. You can then
deploy the EAR file, by installing a new application from the administrative
console.
Mediation modules can
be thought of as one entity. However, SCA modules are
defined by a number of XML files stored in a JAR file.
Figure 2. Simplified
example of an EAR file containing a mediation module.
The EAR
file contains JARs. The utility JAR file contains a mediation module.
Last updated: Wed 06 Dec 2006 07:08:08
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