The Smooks Mediator can be used to apply lightweight transformations on messages in an efficient manner. Smooks is a powerful framework for processing, manipulating and transforming XML. More information about Smooks can be obtained from the official Smooks website.
The Smooks Mediator requires the transformation definition to be passed in as an external resource. This transformation can be specified as a local entry or be stored in the registry. The mediator UI enables you to point the mediator to an existing local entry or a registry resource.
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Syntax
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<smooks [config-key="string"]> <input [type="|text|xml"><]/input>> <output [type="|text|xml"></output>|java"] [property="string"] [action="string"]/> </smooks> |
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UI
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configuration
The parameters available for configuring the Smooks mediator are as follows:
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| Config-Key |
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- Expression - Specify an XPath as an expression to pick the exact message block. Else, the entire 'message body' will be selected by default.
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| The key to access the Smooks configuration. The Smooks configuration should be saved in the Registry as a local entry before it can be used here. Click either Configuration Registry or Governance Registry to select the Smooks configuration from the resource tree. | |
| Input | You can select either XML or Text as the input. |
| Expression | This parameter is used to enter an XPath expression to select the exact message block to which the transformation should be applied. If no expression is entered, the transformation would apply to the entire message body by default. |
| Output | The format of the output. The output type can be XML, Text or Java, and the output can be |
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one of the following.
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Examples
Example 1: Performance tuning
Smooks can be used to split a file and send split results to a JMS endpoint. In this case, having a value other than -1 for jms:highWaterMark in the Smooks configuration file can result in a low throughput for message publishing, since Smooks will spend resources on message counting while the messages are being published. Therefore, it is recommended to use -1 as the highWaterMark value for high throughput values. The following is a sample Smooks configuration file with this setting. For more information on creating the Smooks configuration file, see the documentation in the official Smooks website.
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<?xml version="1.0" encoding="UTF-8"?> <smooks-resource-list xmlns="http://www.milyn.org/xsd/smooks-1.1.xsd" xmlns:core="http://www.milyn.org/xsd/smooks/smooks-core-1.3.xsd" xmlns:ftl="http://www.milyn.org/xsd/smooks/freemarker-1.1.xsd" xmlns:jms="http://www.milyn.org/xsd/smooks/jms-routing-1.2.xsd"> <!-- Filter the message using the SAX Filter (i.e. not DOM, so no intermediate DOM, so we can process huge messages... --> <core:filterSettings type="SAX" /> <!-- Capture the message data 2 seperate DOM model, for "order" and "order-item" fragments... --> <resource-config selector="order,order-item"> <resource>org.milyn.delivery.DomModelCreator</resource> </resource-config> <!-- At each "order-iteam", apply a template to the "order" and "order-item" DOM model... --> <ftl:freemarker applyOnElement="order-item"> <!-- Note in the template that we need to use the special FreeMarker variable ".vars" because of the hyphenated variable names ("order-item"). See http://freemarker.org/docs/ref_specvar.html. --> <ftl:template>/repository/resources/orderitem-split.ftl.txt</ftl:template> <ftl:use> <!-- Bind the templating result into the bean context, from where it can be accessed by the JMSRouter (configured above). --> <ftl:bindTo id="orderItem_xml" /> </ftl:use> </ftl:freemarker> <!-- At each "order-item", route the "orderItem_xml" to the ActiveMQ JMS Queue... --> <jms:router routeOnElement="order-item" beanId="orderItem_xml" destination="smooks.exampleQueue"> <jms:message> <!-- Need to use special FreeMarker variable ".vars" --> <jms:correlationIdPattern>${order.@id}-${.vars["order-item"].@id}</jms:correlationIdPattern> </jms:message> <jms:jndi properties="/repository/conf/jndi.properties" /> <jms:highWaterMark mark="-1" /> </jms:router> </smooks-resource-list> |
Example
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2: Referring files from the Smooks configuration
The following Smooks configuration refers a bindings file named mapping.xml. This file should be saved in <ESB_HOME>/TESTDev directory in order to be accessed via the class path. These bindings will be applied during mediation when the Smooks configuration is included in a Smooks mediator configuration via the Registry.
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<smooks-resource-list xmlns="http://www.milyn.org/xsd/smooks-1.0.xsd">
<resource-config selector="org.xml.sax.driver">
<resource>org.milyn.smooks.edi.EDIReader</resource>
<param name="mapping-model">TESTDev/smooks/mapping.xml</param>
</resource-config>
</smooks-resource-list> |