servicemix-eip

The servicemix-eip component is a routing container where different routing patterns can be deployed as service unit.
This component is based on the great Enterprise Integration Patterns book.

Supported patterns:

• Content-Based Router
• Message Filter
• Pipeline
• Static Recipient List
• Static Routing Slip
• Wire Tap
• XPath Splitter
• Aggregator

In addition, this component can use all ServiceMix flows (including clustered and transactional flows), can be configured to be resilient to crashes and supports full fail-over to another node when clustered.

Using servicemix-eip as a standard JBI component

Installation

Installing the servicemix-eip component can be done in several ways:

• drop the installer zip in an hotdeploy directory monitored by ServiceMix
• using ant tasks

Note that when using ant tasks, the component is not started, you will have to start it manually using ant tasks or a console.

Configuration

TODO: configure a persistent / clustered store

Service Unit packaging

Content of xbean.xml file to be packaged as a SU

<beans xmlns:eip="http://servicemix.apache.org/eip/1.0">

  ... add eip patterns here ...

</beans>

Using servicemix-eip in a ServiceMix xml configuration file

<beans xmlns:sm="http://servicemix.apache.org/config/1.0"
       xmlns:eip="http://servicemix.apache.org/eip/1.0">

  <sm:container ...>
    <sm:activationSpecs>
      <sm:activationSpec>
        <sm:component>
          <eip:component>
            <eip:endpoints>

              ... add eip patterns here ...

            </eip:endpoints>
          </eip:component>
        </sm:component>
      </sm:activationSpec>
      ...
    </sm:activationSpecs>
  </sm:container>
  ...

</beans>

Patterns

Content-Based router

ContentBasedRouter can be used for all kind of content-based routing.
This pattern implements the Content-Based Router pattern.

{snippet:id=content-based-router|lang=xml|url=http://svn.apache.org/repos/asf/incubator/servicemix/trunk/servicemix-eip/src/test/resources/org/apache/servicemix/eip/spring.xml}

Message Filter

MessageFilter allows filtering incoming JBI exchanges.
This pattern implements the Message Filter pattern.

{snippet:id=message-filter|lang=xml|url=http://svn.apache.org/repos/asf/incubator/servicemix/trunk/servicemix-eip/src/test/resources/org/apache/servicemix/eip/spring.xml}

Pipeline

The Pipeline component is a bridge between an In-Only (or Robust-In-Only) MEP and an In-Out MEP. When the Pipeline receives an In-Only MEP, it will send the input in an In-Out MEP to the tranformer destination and forward the response in an In-Only MEP to the target destination.

The old org.apache.servicemix.components.util.PipelineComponent will be deprecated. This one offers the same feature but can be safely clustered and use in a transactional enviromnent.

{snippet:id=pipeline|lang=xml|url=http://svn.apache.org/repos/asf/incubator/servicemix/trunk/servicemix-eip/src/test/resources/org/apache/servicemix/eip/spring.xml}

Static Recipient List

The StaticRecipientList component will forward an input In-Only or Robust-In-Only exchange to a list of known recipients.
This component implements the Recipient List pattern, with the limitation that the recipient list is static.

{snippet:id=static-recipient-list|lang=xml|url=http://svn.apache.org/repos/asf/incubator/servicemix/trunk/servicemix-eip/src/test/resources/org/apache/servicemix/eip/spring.xml}

Static Routing Slip

A RoutingSlip component can be used to route an incoming In-Out exchange through a series of target services.
This component implements the Routing Slip pattern, with the limitation that the routing table is static.
This component only uses In-Out MEPs and errors or faults sent by targets are reported back to the consumer, thus interrupting the routing process.

{snippet:id=static-routing-slip|lang=xml|url=http://svn.apache.org/repos/asf/incubator/servicemix/trunk/servicemix-eip/src/test/resources/org/apache/servicemix/eip/spring.xml}

Wire Tap

A WireTap component can be used to forward a copy of the input message to a listener.
This component implements the WireTap pattern.
It can handle all 4 standard MEPs, but will only send an In-Only MEP to the listener.

{snippet:id=wire-tap|lang=xml|url=http://svn.apache.org/repos/asf/incubator/servicemix/trunk/servicemix-eip/src/test/resources/org/apache/servicemix/eip/spring.xml}

XPath Splitter

The XPathSplitter component implements the Splitter pattern using an xpath expression to split the incoming xml.

{snippet:id=xpath-splitter|lang=xml|url=http://svn.apache.org/repos/asf/incubator/servicemix/trunk/servicemix-eip/src/test/resources/org/apache/servicemix/eip/spring.xml}

SplitAggregator

The SplitAggregator is an aggregator mainly usefull to collect messages that have been created using a splitter.
It relies on several properties that should be set on the exchanges (count, index, correlationId).

{snippet:id=split-aggregator|lang=xml|url=http://svn.apache.org/repos/asf/incubator/servicemix/trunk/servicemix-eip/src/test/resources/org/apache/servicemix/eip/spring.xml}

Tips

ExchangeTarget

All patterns use the <exchange-target /> tag to specify the target of a JBI exchange.
This element has the following attributes:

If you want to target a given interface, just set the interface attribute. Else you have to set the service attribute, and optionally the endpoint attribute if you want to specify the JBI endpoint instead of a service name.

NamespaceContext

Some patterns use XPath expression. To use such expressions on an xml with namespaces, you need to define a NamespaceContext.

{snippet:id=namespace-context|lang=xml|url=http://svn.apache.org/repos/asf/incubator/servicemix/trunk/servicemix-eip/src/test/resources/org/apache/servicemix/eip/spring.xml}

This NamespaceContext can be referenced by a namespaceContext attribute as shown in the XPathSplitter or MessageFilter examples.

Predicates

Some patterns uses predicates to test a given JBI exchange. The only predicate currently implemented is the XPathPredicate, but you can implement your own and deploy it with the service unit.

TODO: link to a page documenting the classpath / location elements for deploying code inside xbean SU

Creating your own patterns

Some classes have been designed to be extensible, this includes:

• org.apache.servicemix.eip.support.AbstractAggregator
• org.apache.servicemix.eip.support.AbstractSplitter