[CONF] Apache ServiceMix: servicemix-saxon (page edited)

Wed, 12 Nov 2008 06:44:30 -0800

Page Edited : SM : servicemix-saxon

servicemix-saxon has been edited by Guillaume Nodet (Nov 12, 2008).

(View changes)

Content:

servicemix-saxon

The servicemix-saxon component is a standard JBI Service Engine for XSLT / XQuery. This component is based on Saxon and supports XSLT 2.0 and XPath 2.0, and XQuery 1.0.

Use of result property

Due to a bug in the latest release of Saxon, the dom value of the result attribute causes exceptions to be thrown. Hence, the default value has been changed to string to avoid problems. This bug only affects the XSLT endpoint, so feel free to use the dom value for XQuery endpoints.

Using servicemix-saxon as a standard JBI component

Installation

Installing the servicemix-saxon 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.

Service Unit packaging

A service unit will typically consist in:

  • an xbean.xml configuration file
  • the associated xslt / xquery document

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

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

  ... add endpoints here ...

</beans>

Using servicemix-saxon in a ServiceMix xml configuration file

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

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

              ... add saxon endpoints here ...

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

</beans>

XSLT Endpoint

The XSLT endpoint can be used to apply an XSLT stylesheet to the incoming exchange and will return the transformed result as the output message.

Simple transformation:

<saxon:xslt service="test:xslt" endpoint="endpoint"
            resource="classpath:transform.xsl" />

Dynamic stylesheet selection:

<saxon:xslt service="test:xslt-dynamic" endpoint="endpoint">
  <saxon:_expression_>
    <bean class="org.apache.servicemix._expression_.PropertyExpression">
      <property name="property" value="xslt.source" />
    </bean>
  </saxon:_expression_>
</saxon:xslt>
Endpoint attributes
Name Type Description Required
resource Spring resource the spring resource pointing to the XSLT stylesheet one of (resource, _expression_)
_expression_ ServiceMix _expression_ _expression_ used to dynamically load the stylesheet one of (resource, _expression_)
wsdlResource Spring resource if set, the wsdl will be retrieved from the given Spring resource no
transformerFactory TransformerFactory TraX factory to create transformers defaults to Saxon implementation
configuration Saxon configuration Saxon configuration no
result String Output result type defaults to dom, possible values are dom, bytes, string
copyAttachments boolean   defaults to true
copyProperties boolean   defaults to true
copySubject boolean   defaults to true
useDomSourceForXslt boolean force the transformation of the xslt stylesheet into a DOM document before giving it to the transformer defaults to true
useDomSourceForContent boolean force the transformation of the incoming JBI message into a DOM document before giving it to the transformer no
parameters Map additional parameters to give to the transformation engine no

Using properties and parameters

All properties defined on the JBI exchange and input JBI message will be available for use inside the XSLT stylesheet as parameters.
In addtion to those properties and the one specified in the parameters property on the endpoint, the following objects are also available:

  • exchange: the JBI exchange
  • in: the input JBI NormalizedMessage
  • component: the XsltEndpoint instance being called

All those parameters can be accessed using XSLT standard ways.
For example:

<xsl:stylesheet xmlns:xsl='http://www.w3.org/1999/XSL/Transform' version='1.0'>
  <xsl:param name="stringParam"/>
  <xsl:param name="integerParam"/>
  ...
</xsl:stylesheet>

and the configuration of those values on the endpoint (in case they are not available on the JBI exchange / message):

<saxon:xslt service="test:xslt-params" endpoint="endpoint"
            resource="classpath:parameter-test.xsl">
  <property name="parameters">
    <map>
      <entry key="stringParam" value="cheeseyCheese"/>
      <entry key="integerParam">
        <bean class="java.lang.Integer">
          <constructor-arg index="0" value="4002"/>
        </bean>
      </entry>
    </map>
  </property>
</saxon:xslt>

XSLT Proxy

One common use case is the need to transform a request coming from a service and send it to another service and do the same with the response. A simple example is the need to translate the request and responses between two SOAP endpoints. Such a use case could be implemented using two XSLT endpoints and an EIP StaticRoutingSlip. However, there are some drawbacks, as the operation is lost in the process, and a static routing slip can not be used to process InOnly exchanges.

The 4.0 version of servicemix-saxon provides such a feature in a single endpoint:

<saxon:proxy service="test:proxy" endpoint="endpoint"
             resource="classpath:transform-in.xsl"
             outResource="classpath:transform-out.xsl"
             faultResource="classpath:transform-fault.xsl">
  <saxon:target>
    <saxon:exchange-target service="test:echo" />
  </saxon:target>
</saxon:proxy>
Endpoint attributes
Name Type Description Required
resource Spring resource the spring resource pointing to the XSLT stylesheet used to transform the input message no
outResource Spring resource the spring resource pointing to the XSLT stylesheet used to transform the output message no
faultResource Spring resource the spring resource pointing to the XSLT stylesheet used to transform the fault message no
_expression_ ServiceMix _expression_ _expression_ used to dynamically load the stylesheet. If set, it will prevail against all resource, outResource and faultResource attributes no
wsdlResource Spring resource if set, the wsdl will be retrieved from the given Spring resource no
transformerFactory TransformerFactory TraX factory to create transformers defaults to Saxon implementation
configuration Saxon configuration Saxon configuration no
result String Output result type defaults to dom, possible values are dom, bytes, string
copyAttachments boolean   defaults to true
copyProperties boolean   defaults to true
copySubject boolean   defaults to true
target ExchangeTarget the destination where the transformed exchange will be sent to yes

XQuery endpoint

The XQuery endpoint can be used to apply a selected XQuery to the input document.

Simple XQuery:

<saxon:xquery service="test:xquery" endpoint="endpoint"
              resource="classpath:query.xq" />

Inlined XQuery with specific output configuration:

<saxon:xquery service="test:xquery-inline" endpoint="endpoint">
  <saxon:query>
    for $x in /bookstore/book
    where $x/price > 30
    return $x/title
  </saxon:query>
  <saxon:outputProperties>
    <saxon:property key="{http://saxon.sf.net/}wrap-result-sequence">yes</saxon:property>
  </saxon:outputProperties>
</saxon:xquery>

Dynamic selection of XQuery:

<saxon:xquery service="test:xquery-dynamic" endpoint="endpoint">
  <saxon:_expression_>
    <bean class="org.apache.servicemix._expression_.PropertyExpression">
      <property name="property" value="xquery.source" />
    </bean>
  </saxon:_expression_>
</saxon:xquery>
Endpoint attributes
Name Type Description Required
query String inlined XQuery one of (query, resource, _expression_)
resource Spring resource the spring resource pointing to the XQuery one of (query, resource, _expression_)
_expression_ ServiceMix _expression_ _expression_ used to dynamically load the xquery one of (query, resource, _expression_)
wsdlResource Spring resource if set, the wsdl will be retrieved from the given Spring resource no
outputProperties Map Saxon specific output properties no
configuration Saxon configuration Saxon configuration no
result String Output result type defaults to dom, possible values are dom, bytes, string
copyAttachments boolean   defaults to true
copyProperties boolean   defaults to true
copySubject boolean   defaults to true

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