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Transformation Feature
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The CXF Transformation feature provides for a flexible and fast way to do dynamic transformation of inbound and/or outbound XML messages.
This feature can be used in a number of cases: dropping the namespace of the outbound messages, qualifying the incoming message, changing namespaces, appending or dropping elements and converting attributes to elements.
The "outTransformElements", "inTransformElements", "outDropElements", "inDropElements", "outAppendElements", "inAppendElements" and "attributesAsElements" properties can be used.
On the outbound service side, some of the transformation features (e.g. "outTransformElements", "outDropElements") may not work properly prior to CXF versions 3.2.6 and 3.1.17. This is due to outputstream optimization that CXF does. In this case, the outputstream optimization must be explicitly disabled for the outbound transformation feature to work properly by setting the JAX-WS/JAX-RS property "disable.outputstream.optimization" to "true".
Spring configuration
Changing input and output element names and namespaces
"outTransformElements" map property can be used to change the output element names and change or drop namespaces. Keys are the elements to be changed, values are the new element names. Example:
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Feature {span} {toc} The CXF Transformation feature provides for a flexible and fast way to do the dynamic transformations of the inbound and/or outbound XML messages. This feature can be used in a number of cases: dropping the namespace of the outbound messages, qualifying the incoming message, changing namespaces, appending or dropping elements and converting attributes to elements. The "outTransformElements", "inTransformElements", "outDropElements", "inDropElements", "outAppendElements", "inAppendElements" and "attributesAsElements" properties can be used. h1. Spring configuration h2. Changing input and output element names and namespaces "outTransformElements" map property can be used to change the output element names and change or drop namespaces. Keys are the elements to be changed, values are the new element names. Example: {code:xml} <bean id="transformFeature" class="org.apache.cxf.feature.StaxTransformFeature"> <property name="outTransformElements"> <map> <!-- change "book" to "thebook" --> <entry key="book" value="thebook"/> <!-- drop the namespace from "book" --> <entry key="{http://books}book" value="book"/> <!-- qualify "book" with "http://books" --> <entry key="book" value="{http://books}thebook"/> <!-- change namespace to "http://books" for all the elements with the "http://book" namespace --> <entry key="{http://book}*" value="{http://books}*"/> </map> </property> </bean> {code} |
"inTransformElements"
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map
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property
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can
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be
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used
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to
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change
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the
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input
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element
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names
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and
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change
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or
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drop
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namespaces.
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See
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the
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"outTransfromElements"
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property
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description
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for
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an
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example.
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Appending
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new
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input and output
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elements
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"outAppendElements" and "inAppendElements" map properties can be used to append new simple or qualified elements to the output/input in a number of ways. Keys are the elements the new elements will be appended before, values are the new elements. Examples:
Append-Pre-Wrap
Using inAppendsElements:
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map property can be used to append new simple or qualified elements to the output. Keys are the elements the new elements will be appended before, values are the new elements. Examples: {code:xml} <bean id="transformFeature" class="org.apache.cxf.feature.StaxTransformFeature"> <property name="outAppendElementsinAppendElements"> <map> <!-- get "book" wrapped with the new "thebook" element--> <entry key="book" value="thebook"/> </map> </property> </bean> {code} Only |
Using outAppendsElements:
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<bean id="transformFeature" class="org.apache.cxf.feature.StaxTransformFeature">
<property name="outAppendElements">
<map>
<!-- get "book" wrapped with the new "thebook" element-->
<entry key="book" value="thebook"/>
</map>
</property>
</bean>
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Append-Post-Wrap
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this so-called Append-Wrap is currently supported for out elements. h2. Appending new input elements "inAppendElements" map property can be used to append new simple or qualified elements to the input in a number of ways. h3. Append-Pre-Wrap {code:xml} <bean id="transformFeature" class="org.apache.cxf.feature.StaxTransformFeature"> <property name="inAppendElements"> <map> <!-- get all "book" children elements wrapped with the new "thebook" element--> <entry key="book" value using the "/" convention. --> <entry key="book/" value="thebook"/> </map> </property> </bean> {code} h3. |
Append-Pre-Include
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Post-Wrap {code:xml} <bean id="transformFeature" class="org.apache.cxf.feature.StaxTransformFeature"> <property name="inAppendElements"> <map> <!-- append get all "book" children elements wrapped with the newnew simple "thebook" element with a text value '2' before using the "/book" convention. element --> <entry key="book/" value="thebook=2"/> </map> </property> </bean> {code} h3. |
Append-
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Post-Include
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{code:xml} <bean id="transformFeature" class="org.apache.cxf.feature.StaxTransformFeature"> <property name="inAppendElements"> <map> <!-- append new simple "thebook" element with a text value '2' using beforethe "/" convention as the last child element within the "book" element --> <entry key="book/" value="thebook=2"/> </map> </property> </bean> {code} h3. Append-Post-Include {code:xml} <bean id="transformFeature" class="org.apache.cxf.feature.StaxTransformFeature"> <property name="inAppendElements"> <map> <!-- append new simple "thebook" element with a text value '2' after "the book", using a '/' convention --> <entry |
Comparing four append modes
input | append-pre-wrap
| append-post-wrap | append-pre-include | append-post-include |
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key="book" value="thebook" | key="book/" value="thebook" | key="book" value="thebook=2" | key="book/" |
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value="thebook=2" |
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<sales> |
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title> |
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book> | <sales> | <sales> | <sales> | <sales> |
Replacing text content
It's possible to replace the text content of a given simple element only on the input and output, for example:
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<bean id="transformFeature" class="org.apache.cxf.feature.StaxTransformFeature">
<property name="inAppendElements">
<map>
<!-- replace the text content of {ns}a element with the 'new Text' value -->
<entry key="{ns}a" value="{ns}a=new Text"/>
</map
</property>
</bean>
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Dropping output and input elements
"outDropElements" and "inDropElements" list properties can be used to drop output and input elements. Note that children elements if any of a given dropped element are not affected. Please see the "outDropElements" property description for an example. It's a so-called "shallow" drop.
Additionally, outTransformElements and inTransformElements property can be used to deep-drop an element and all of its children if any, for example:
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bean> {code} h2. Replacing text content It's possible to replace the text content of a given simple element only on the input, for example: {code:xml} <bean id="transformFeature" class="org.apache.cxf.feature.StaxTransformFeature"> <property name="inAppendElements"> <map> <!-- replace the text content of {ns}a element with the 'new Text' value --> <entry key="{ns}a" value="{ns}a=new Text"/> </map </property> </bean> {code} h2. Dropping output elements "outDropElements" list property can be used to drop output elements. Note that children elements if any of a given dropped element are not affected. Examples: {code:xml} <bean id="transformFeature" class="org.apache.cxf.feature.StaxTransformFeature"> <property name="outDropElements"> <list> <!-- shallow drop 'index' and '{http://numbers}number' elements --> <value>{http://numbers}number</value> <value>index</value> </list> </property> </bean> {code} h2. Dropping input elements "inDropElements" list property can be used to drop input elements. Note that children elements if any of a given dropped element are not affected. Please see the "outDropElements" property description for an example. Additionally, inTransformElements property can be used to deep-drop an element and all of its children if any, for example: {code:xml} <bean id="transformFeature" class="org.apache.cxf.feature.StaxTransformFeature"> <property name="outTransformElements"> <map> <!-- drop "book" and all of its children, using an empty value convention --> <entry key="book" value=""/> </map> </property> </bean> {code} h2. Converting attributes to elements |
Converting attributes to elements
"attributesAsElements"
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boolean
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property
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can
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be
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used
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to
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have
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attributes
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serialized
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as
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elements
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on
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the
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output
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only.
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The
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combination
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of
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"attributesAsElements"
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and
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"outDropElements"
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properties
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can
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be
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used
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to
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have
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certain
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attributes
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ignored
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in
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the
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output
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by
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turning
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them
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into
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elements
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and
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then
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blocking
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them.
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Input
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Transformation
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and
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Redirection
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Consider
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the
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case
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where
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a
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new
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endpoint
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has
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been
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introduced
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but
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some
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of
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the
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existing
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clients
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have
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not
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been
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updated
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yet
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to
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work
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with
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the
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new
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endpoint,
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they
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are
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still
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unaware
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of
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it.
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In
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this
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case
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you
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may
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want
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to
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keep
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the
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CXFServlet
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serving
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the
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old
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clients
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but
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make
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it
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redirect
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them
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to
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a
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new
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CXFServlet
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serving
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a
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new
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endpoint
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only.
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Now,
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in
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order
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to
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serve
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the
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old
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clients
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one
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needs
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to
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apply
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a
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transform
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feature,
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however
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the
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new
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clients
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should
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not
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be
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affected.
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Thus
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the
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feature
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can
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be
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configured
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such
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that
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it's
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only
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triggered
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if
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a
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certain
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contextual
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property
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has
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been
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set
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on
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a
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current
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Message.
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In
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this
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case
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the
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feature
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should
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only
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apply
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to
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the
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old
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redirected
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clients:
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{code:xml}
<bean id="transformFeatureRest" class="org.apache.cxf.feature.StaxTransformFeature">
<!--
apply the transformation only if the boolean property with the given name
is set to true on the message
-->
<property name="contextPropertyName" value="http.service.redirection"/>
<!-- the transform configuration -->
</bean>
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Configuring the feature from the code
The feature can be configured from the code for JAX-WS or JAX-RS clients and endpoints.
JAX-WS
Here is how a JAX-WS client can be configured:
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CustomerServiceService service = new CustomerServiceService(); CustomerService customerService = service.getCustomerServicePort(); Client client = ClientProxy.getClient(customerService); // drop namespace from all elements qualified by 'http://customers' Map<String, String> outTransformMap = Collections.singletonMap("{http://customers}*", "*"); org.apache.cxf.interceptor.transform.TransformOutInterceptor transformOutInterceptor = new org.apache.cxf.interceptor.transform.TransformOutInterceptor(); transformOutInterceptor.setOutTransformElements(outTransformMap); client.getOutInterceptors().add(transformOutInterceptor{code} h1. Configuring the feature from the code The feature can be configured from the code for JAX-WS or JAX-RS clients and endpoints. h2. JAX-WS Here is how a JAX-WS client can be configured: {code:java} CustomerServiceService service = new CustomerServiceService(); CustomerService customerService = service.getCustomerServicePort(); Client client = ClientProxy.getClient(customerService); // dropqualify namespacethe fromincoming all'customer' elementselement qualified bywith 'http://customers' Map<String, String> outTransformMapinTransformMap = Collections.singletonMap(("customer", "{http://customers}*", "*customer"); org.apache.cxf.interceptor.transform.TransformOutInterceptorTransformInInterceptor transformOutInterceptortransformInInterceptor = new org.apache.cxf.interceptor.transform.TransformOutInterceptor().TransformInInterceptor(); transformInInterceptor.setInTransformElements(inTransformMap); client.getInInterceptors().add(transformInInterceptor); |
JAX-RS
Here is how a JAX-RS client can be configured:
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CustomerService customerServiceProxy = JAXRSClientFactory.create(endpointAddress, CustomerService.class); ClientConfiguration config = WebClient.getConfig(customerServiceProxy); // or //WebClient client = WebClient.create(endpointAddress); //ClientConfiguration config = WebClient.getConfig(client); // drop namespace from all elements qualified by 'http://customers' Map<String, String> outTransformMap = Collections.singletonMap("{http://customers}*", "*"); org.apache.cxf.interceptor.transform.TransformOutInterceptor transformOutInterceptor = new org.apache.cxf.interceptor.transform.TransformOutInterceptor(); transformOutInterceptor.setOutTransformElements(outTransformMap); config.getOutInterceptors().add(transformOutInterceptor); // qualify the incoming 'customer' element with; transformOutInterceptor.setOutTransformElements(outTransformMap); client.getOutInterceptors().add(transformOutInterceptor); // qualify the incoming 'customer' element with 'http://customers' Map<String, String> inTransformMap = Collections.singletonMap("customer", "{http://customers}customer"); org.apache.cxf.interceptor.transform.TransformInInterceptor transformInInterceptor = new org.apache.cxf.interceptor.transform.TransformInInterceptor(); transformInInterceptor.setInTransformElements(inTransformMap); client.getInInterceptors().add(transformInInterceptor); {code} h2. JAX-RS Here is how a JAX-RS client can be configured: {code:java} CustomerService customerServiceProxy = JAXRSClientFactory.create(endpointAddress, CustomerService.class); ClientConfiguration config = WebClient.getConfig(customerServiceProxy); // or //WebClient client = WebClient.create(endpointAddress); //ClientConfiguration config = WebClient.getConfig(client); // drop namespace from all elements qualified by 'http://customers' Map<String, String> outTransformMapinTransformMap = Collections.singletonMap("customer", "{http://customers}*customer", "*"); org.apache.cxf.interceptor.transform.TransformOutInterceptorTransformInInterceptor transformOutInterceptortransformInInterceptor = new org.apache.cxf.interceptor.transform.TransformOutInterceptorTransformInInterceptor(); transformOutInterceptortransformInInterceptor.setOutTransformElementssetInTransformElements(outTransformMapinTransformMap); config.getOutInterceptorsgetInInterceptors().add(transformOutInterceptortransformInInterceptor); // qualify the incoming 'customer' element with 'http://customers' Map<String, String> inTransformMap = Collections.singletonMap("customer", "{http://customers}customer"); org.apache.cxf.interceptor.transform.TransformInInterceptor transformInInterceptor = new org.apache.cxf.interceptor.transform.TransformInInterceptor(); transformInInterceptor.setInTransformElements(inTransformMap); config.getInInterceptors().add(transformInInterceptor); {code} |
Transform interceptors and phases
TransformInInterceptor and TransformOutInterceptor interceptors run in POST_STREAM and PRE_STREAM phases.
In some cases it may be needed to change the phase, for example, the in transformation has to be applied after the encrypted payload has been decrypted and its signature checked. For such transformations to succeed TransformInInterceptor will need to be created with a constructor accepting a 'phase' String parameter, for the interceptor to run after the decrypption and signature validation actions have been performed.
Default namespace on the output
The 'outDefaultNamespace' feature property can be used to enforce the default namespace declaration. The value of this property has to match one of the out namespaces.