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A.2. Common Elements

Overview

When configuring ServiceMix EIP patterns in a ServiceMix configuration file, there are some common elements that occur in many of the pattern schemas. This section provides a brief overview of these common elements and explains how they can be mapped to equivalent constructs in Apache Camel.

Exchange target

All of the patterns supported by ServiceMix EIP use the eip:exchange-target element to specify JBI target endpoints. Table A.1, “Mapping the Exchange Target Element” shows examples of how to map sample eip:exchange-target elements to Apache Camel endpoint URIs, where it is assumed that the test prefix maps to the http://progress.com/demos/test namespace.

Table A.1. Mapping the Exchange Target Element

ServiceMix EIP TargetApache Camel Endpoint URI
<eip:exchange-target interface="HelloWorld" /> jbi:interface:HelloWorld
<eip:exchange-target service="test:HelloWorldService" /> jbi:service:http://progress.com/demos/test/HelloWorldService
<eip:exchange-target service="test:HelloWorldService" endpoint="secure" /> jbi:service:http://progress.com/demos/test/HelloWorldService/secure
<eip:exchange-target uri="service:test:HelloWorldService" /> jbi:service:http://progress.com/demos/test/HelloWorldService

Predicates

The ServiceMix EIP component allows you to define predicate expressions in the XPath language. For example, XPath predicates can appear in eip:xpath-predicate elements or in eip:xpath-splitter elements, where the XPath predicate is specified using an xpath attribute.
ServiceMix XPath predicates can easily be migrated to equivalent constructs in Apache Camel: that is, either the xpath element (in XML configuration) or the xpath() command (in Java DSL). For example, the message filter pattern in Apache Camel can incorporate an XPath predicate as follows:
<route>
  <from uri="jbi:endpoint:http://progress.com/demos/test/messageFilter/endpoint">
  <filter>
   <xpath>count(/test:world) = 1</xpath>
   <to uri="jbi:service:http://progress.com/demos/test/trace3"/>
  </filter>
</route>
Where the xpath element specifies that only messages containing the test:world element will pass through the filter.
Note
Apache Camel also supports a wide range of other scripting languages including XQuery, PHP, Python, and Ruby, which can be used to define predicates. For details of all the supported predicate languages, see Expression and Predicate Languages.

Namespace contexts

When using XPath predicates in the ServiceMix EIP configuration, it is necessary to define a namespace context using the eip:namespace-context element. The namespace is then referenced using a namespaceContext attribute.
When ServiceMix EIP configuration is migrated to Apache Camel, there is no need to define namespace contexts, because Apache Camel allows you to define XPath predicates without referencing a namespace context. You can simply drop the eip:namespace-context elements when you migrate to Apache Camel.