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Messaging systems

Pipeline

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pipeline pipeline

There is a simple syntax available for specifying pipeline, by simple putting to or → between the different steps in the pipeline.

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The above examples also show you how other languages like XPath can be within the Scala DSL.

Recipient list

You can handle a static recipient list with a multicast or pipeline , but this EIP is usually applied when you want to dynamically determine the name(s) of the next endpoint(s) to route to. Use the recipients() method with a function literal (Exchange => Any) that returns the endpoint name(s). In the example below, the target endpoint name can be found in the String message starting at position 21.

{snippet:id=simple|lang=java|url=activemq/camel/trunk/components/camel-scala/src/test/scala/org/apache/camel/scala/dsl/RecipientListRouteTest.scala}

Because the recipients() method just takes a function literal, you can basically use any kind of valid Scala code to determine the endpoint name. Have a look at the next example which uses pattern matching to figure out where to send the message:

{snippet:id=pattern|lang=java|url=activemq/camel/trunk/components/camel-scala/src/test/scala/org/apache/camel/scala/dsl/RecipientListRouteTest.scala}

Again, we can also use the same thing in a more block-like syntax. For this example, we use the Scala DSL's support for JXPath to determine the target.

{snippet:id=block|lang=java|url=activemq/camel/trunk/components/camel-scala/src/test/scala/org/apache/camel/scala/dsl/RecipientListRouteTest.scala}

TODO

TODO: Create a Scala alternative and example for every EIP available on http://activemq.apache.org/camel/enterprise-integration-patterns.html

• Message Channel
• Message
• Message Router
• Message Translator
• Message Endpoint
• Point to Point Channel
• Publish Subscribe Channel
• Dead Letter Channel
• Guaranteed Delivery
• Message Bus
• Correlation IdentifierRecipient List
• Aggregator
• Resequencer
• Routing Slip
• Throttler
• Delayer
• Load Balancer
• Multicast
• Content Enricher
• Content Filter
• Normalizer
• Messaging Mapper
• Event Driven Consumer
• Polling Consumer
• Competing Consumers
• Message Dispatcher
• Selective Consumer
• Durable Subscriber
• Idempotent Consumer
• Transactional Client
• Messaging Gateway
• Service Activator
• Wire Tap