[CONF] Apache ServiceMix > servicemix-eip

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servicemix-eip Page edited by Jean-Baptiste Onofré Changes (19) h1. servicemix-eip {info} The servicemix-eip component is deprecated. Please use [servicemix-camel] which provides [Apache Camel|http://camel.apache.org] to implement all available Enterprise Integration Patterns. {info} 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|http://www.enterpriseintegrationpatterns.com/index.html] book. {info:title=Apache Camel} Note that [Apache Camel|http://activemq.apache.org/camel/|a powerful rule based routing and mediation engine which provides a POJO based implementation of the Enterprise Integration Patterns using an extremely powerful fluent API] provides a full set of [Enterprise Integration Patterns|http://activemq.apache.org/camel/enterprise-integration-patterns.html] both from [Java code|http://activemq.apache.org/camel/dsl.html] or [Spring XML|http://activemq.apache.org/camel/spring.html] which you may want to consider as an alternative to ServiceMix EIP. For more details see the [servicemix-camel] component, the [comparison of ServiceMix EIP and Camel|http://activemq.apache.org/camel/how-does-camel-compare-to-servicemix-eip.html] and [how Camel works with JBI endpoints|http://activemq.apache.org/camel/jbi.html]. {info} Supported patterns: * [Content-Based Router|#Content-Based router] ... 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. h2. Using servicemix-eip as a standard JBI component h2. Maven Archetype You can create a EIP Service Unit using the servicemix-eip-service-unit archetype: h3. Installation {code} mvn archetype:create \ -DarchetypeGroupId=org.apache.servicemix.tooling \ -DarchetypeArtifactId=servicemix-eip-service-unit \ -DarchetypeVersion=2010.01 \ -DgroupId=your.group.id \ -DartifactId=your.artifact.id \ -Dversion=your-version {code} 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|Ant Tasks] h2. Endpoint Configuration Note that when using ant tasks, the component is not started, you will have to start it manually using ant tasks or a console. The EIP configuration is defined directly in the xbean.xml: h3. Configuration For a complete list of configuration options for the supported EIPs, take a look at the XSD and generated HTML for this component on the [Xml schemas] page. TODO: configure a persistent / clustered store h3. Service Unit packaging Content of xbean.xml file to be packaged as a SU {code:xml} <beans xmlns:eip="http://servicemix.apache.org/eip/1.0"> ... add eip patterns here ... </beans> {code} <bean xmlns:eip="http://servicemix.apache.org/eip/1.0"> ... add EIP patterns here ... </bean> {code} h2. Using servicemix-eip in a ServiceMix xml configuration file For example: {code:xml} <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> {code} <bean xmlns:eip="http://servicemix.apache.org/eip/1.0" xmlns:replaceMe="http://servicemix.apache.org/replaceMe"> <eip:static-recipient-list service="replaceMe:serviceName" endpoint="static-recipient-list"> <eip:recipients> <eip:exchange-target service="replaceMe:serviceName" endpoint="targetEndpoint" /> <eip:exchange-target service="replaceMe:serviceName" endpint="otherEndpoint" /> </eip:recipients> </eip:static> </bean> {code} h2. Supported EIP Patterns ... Full Content servicemix-eip The servicemix-eip component is deprecated. Please use servicemix-camel which provides Apache Camel to implement all available Enterprise Integration Patterns. 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 Content Enricher Resequencer AsyncBridge 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. Maven Archetype You can create a EIP Service Unit using the servicemix-eip-service-unit archetype: mvn archetype:create \ -DarchetypeGroupId=org.apache.servicemix.tooling \ -DarchetypeArtifactId=servicemix-eip-service-unit \ -DarchetypeVersion=2010.01 \ -DgroupId=your.group.id \ -DartifactId=your.artifact.id \ -Dversion=your-version Endpoint Configuration The EIP configuration is defined directly in the xbean.xml: <bean xmlns:eip="http://servicemix.apache.org/eip/1.0"> ... add EIP patterns here ... </bean> For example: <bean xmlns:eip="http://servicemix.apache.org/eip/1.0" xmlns:replaceMe="http://servicemix.apache.org/replaceMe"> <eip:static-recipient-list service="replaceMe:serviceName" endpoint="static-recipient-list"> <eip:recipients> <eip:exchange-target service="replaceMe:serviceName" endpoint="targetEndpoint" /> <eip:exchange-target service="replaceMe:serviceName" endpint="otherEndpoint" /> </eip:recipients> </eip:static> </bean> Supported EIP Patterns Content-Based router ContentBasedRouter can be used for all kind of content-based routing. This pattern implements the Content-Based Router pattern. <eip:content-based-router service="test:router" endpoint="endpoint"> <eip:rules> <eip:routing-rule> <eip:predicate> <eip:xpath-predicate xpath="count(/test:echo) = 1" namespaceContext="#nsContext" /> </eip:predicate> <eip:target> <eip:exchange-target uri="endpoint:http://test/pipeline/endpoint" /> </eip:target> </eip:routing-rule> <eip:routing-rule> <!-- there is no predicate, so this is the default destination --> <eip:target> <eip:exchange-target service="test:recipients" /> </eip:target> </eip:routing-rule> </eip:rules> </eip:content-based-router> Message Filter MessageFilter allows filtering incoming JBI exchanges. As it drops unwanted messages and in an InOut exchange a response is required, MessageFilter and InOut MEPs cannot be used together. This pattern implements the Message Filter pattern. <eip:message-filter service="test:messageFilter" endpoint="endpoint"> <eip:target> <eip:exchange-target service="test:trace3" /> </eip:target> <eip:filter> <eip:xpath-predicate xpath="count(/test:world) = 1" namespaceContext="#nsContext"/> </eip:filter> </eip:message-filter> 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. <eip:pipeline service="test:pipeline" endpoint="endpoint"> <eip:transformer> <eip:exchange-target service="test:routingSlip" /> </eip:transformer> <eip:target> <eip:exchange-target service="test:trace2" /> </eip:target> </eip:pipeline> In the default configuration, faults sent by the transformer component are sent back to the consumer as faults if the exchange MEP supports them, or as errors (for InOnly exchanges). This behavior can be changed by setting the sendFaultsToTarget attribute to true, in which case faults will be sent to the target component, or by adding a faultsTarget element where faults should be sent. 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. <eip:static-recipient-list service="test:recipients" endpoint="endpoint"> <eip:recipients> <eip:exchange-target service="test:messageFilter" /> <eip:exchange-target service="test:trace4" /> </eip:recipients> </eip:static-recipient-list> 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. <eip:static-routing-slip service="test:routingSlip" endpoint="endpoint"> <eip:targets> <eip:exchange-target service="test:echo" /> <eip:exchange-target service="test:echo" /> </eip:targets> </eip:static-routing-slip> Wire Tap A WireTap component can be used to forward a copy of the input message to a listener in a proxy fashion. This component implements the WireTap pattern. It can handle all four standard MEPs, but will only send an In-Only MEP to the listener. The originating service must be configured to send messages to the WireTap directly. In the case of an In-Out MEP, this means that the WireTap needs to be configured to send the exchange along to the destination service. <eip:wire-tap service="test:wireTap" endpoint="endpoint"> <eip:target> <eip:exchange-target service="test:xpathSplitter" /> </eip:target> <eip:inListener> <eip:exchange-target service="test:trace1" /> </eip:inListener> </eip:wire-tap> Similar to the example above, the WireTap can also be used: to forward the output message of an exchange using <eip:outListener/> to forward the fault message of an exchange using <eip:faultListener/> XPath Splitter The XPathSplitter component implements the Splitter pattern using an xpath _expression_ to split the incoming xml. <eip:xpath-splitter service="test:xpathSplitter" endpoint="endpoint" xpath="/*/*" namespaceContext="#nsContext"> <eip:target> <eip:exchange-target uri="service:http://test/router" /> </eip:target> </eip:xpath-splitter> 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). <eip:split-aggregator service="test:aggregator" endpoint="endpoint"> <eip:target> <eip:exchange-target service="test:trace5" /> </eip:target> </eip:split-aggregator> Content Enricher With a Content Enricher you can extract additional information from a source and add this information to your message. This is useful if the calling service for example extracts a 'userID' and your target system is only aware of a 'userName'. By using the Content-Enricher you could extract this information from a source system and add this additional information ('userName') to your message. <eip:content-enricher service="test:contentEnricher" endpoint="endpoint"> <eip:enricherTarget> <eip:exchange-target service="test:additionalInformationExtracter" /> </eip:enricherTarget> <eip:target> <eip:exchange-target service="test:myTarget" /> </eip:target> </eip:content-enricher> Resequencer A resequencer re-orders incoming In-Only or Robust-In-Only exchanges and sends them synchronously to a targets service. Synchronous sending ensures that messages arrive in correct order at the target service. This component implements the Resequencer pattern. It works on (continuous) streams of message exchanges using a timeout policy. Since the resequencer doesn't make batch reads there's no need to know the number of messages to be re-ordered in advance (although a capacity parameter prevents the resequencer from running out of memory). If the maximum out-of-sequence time difference between messages in a message stream is known, the resequencer's timeout parameter should be set to this value (milliseconds). In this case it is guaranteed that all elements of a stream are delivered in correct order to the target service. The lower the timeout value is compared to the out-of-sequence time difference the higher is the probability for out-of-sequence messages sent by this resequencer. Large timeout values should be supported by sufficiently high capacity values. For comparing elements of a sequence the resequencer component can be configured with a sequence element comparator. A default comparator is provided that compares message exchanges based on Long sequence numbers. This comparator expects the sequence number to be the value of the org.apache.servicemix.eip.sequence.number property of the exchanges's in-NormalizedMessage. The name of the property can be customized in the comparator configuration (see below). You may also provide a custom comparator by implementing the SequenceElementComparator interface. <eip:resequencer service="sample:Resequencer" endpoint="ResequencerEndpoint" comparator="#comparator" capacity="100" timeout="2000"> <eip:target> <eip:exchange-target service="sample:SampleTarget" /> </eip:target> </eip:resequencer> <!-- Configure default comparator with custom sequence number property --> <eip:default-comparator id="comparator" sequenceNumberKey="seqnum"/> A running example can be downloaded from here. In this example, a custom-coded message sender sends messages in "wrong" order to the resequencer. The resequencer re-orders these messages and (synchronously) sends them to a file sender-endpoint. The file sender-enpoint writes the messages (in proper order) to the work/output directory. AsyncBridge The AsyncBridge is the opposite of the Pipeline: it bridges an InOut exchange with two InOnly exchanges. The AsyncBridge expects an InOut mep as input. It then uses the exchange id of the InOut mep as the correlation id and creates an InOnly message by copying the input message and sends it to the target (with the correlation id set as a property). Next it expects an InOnly to come back with the same correlation id property. When this happens, the message is copied to the out message of the original exchange and sent back. If no response is received during the configured amount of time (timeout property in milliseconds), an error will be sent back to the original consumer. <eip:async-bridge service="sample:AsyncBridge" endpoint="AsyncBridgeEndpoint" <eip:target> <eip:exchange-target service="sample:SampleTarget" /> </eip:target> </eip:async-bridge> Correlation Id There is a convention between the AsyncBridge and the target on how the correlation id is transmitted. The correlation id can only be transmitted from the AnsycBridge to the target using a message property . The property name can be customized. On the other hand, the correlation id coming back from the target could be set in a message property or the message payload. The AsyncBridge could use an _expression_ to extract the correlation id from the message returning from the target.  <eip:async-bridge          service="sample:AsyncBridge"          endpoint="AsyncBridgeEndpoint"          responseCorrIdProperty="correlationIdProperty"          responseCorrId="#responseCorrIdExpression">          <eip:target>              <eip:exchange-target service="sample:SampleTarget" />          </eip:target>  </eip:async-bridge>      <bean id="responseCorrIdExpression" class="org.apache.servicemix._expression_.JAXPStringXPathExpression" >        <contructor-arg value="/my-response/message/@corrId"/>  </bean>    As you can see from the sample above the responseCorrIdProperty is used to set the name of the property that the target will query to get the correlation id sent by the AsyncBridge. In other words, the target will do something like this to extract the correlation id:  String correlationId = exchange.getProperty("correlationIdProperty"); The responseCorrId is set with an instance of type org.apache.servicemix._expression_._expression_, in this case the class org.apache.servicemix._expression_.JAXPStringXPathExpression. This _expression_ resolves the location of the correlation id coming back from the target. In the above example the _expression_ shows that the correlation id comes as part of the message payload in an attribute called "corrId" of the /my-response/message element. In a similar manner the class org.apache.servicemix._expression_.PropertyExpression could have been used to locate the correlation id in a message property. Tips ExchangeTarget All patterns use the <exchange-target /> tag to specify the target of a JBI exchange. This element has the following attributes: Name Type Description interface QName the QName of the target interface. One of service or interface attribute is required operation QName the QName of the target operation (optional) service QName the QName of the target service. One of service or interface attribute is required endpoint String the name of the target JBI endpoint, only used when service is set uri String uri used to target the exchange (see URIs) 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. <eip:namespace-context id="nsContext"> <eip:namespaces> <eip:namespace prefix="test">http://test</eip:namespace> </eip:namespaces> </eip:namespace-context> 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 Configuring temporary message storage Many of the pattern implementation need to store MessageExchanges temporarily. An example: the aggregator will need to keep track of the MessageExchange it is aggregating. By default, the EIPs use a plain MemoryStoreFactory to create in-memory stores, but there are other options. If you set the timeout property on the MemoryStoreFactory, it will evict old object from the in-memory store to avoid a memory leak. You can also use a JDBCStoreFactory to store data in a database instead of in memory. Example: to use an in-memory store with timeout for a storing active and closed aggregations in a <split-aggregator/>, you can do <eip:split-aggregator service="test:aggregator" endpoint="endpoint" storeFactory="#StoreFactory" closedAggregateStoreFactory="#StoreFactory"> <eip:target> <eip:exchange-target service="test:trace5" /> </eip:target> </eip:split-aggregator> <bean id="StoreFactory" class="org.apache.servicemix.store.MemoryStoreFactory"> <property name="timeout" value="120000"/> <!-- 2 minute timeout --> </bean> 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 Change Notification Preferences View Online | View Changes | Add Comment