No longer tied to Java: It no longer uses SAX, StaX, or DOM types. Mule 4 is now strongly typed and we have mime type information about which data is in XML format. The runtime does the rest. All XML documents are represented as either Strings or streams. This means the following no longer exist (and are no longer needed):
Mule 3 Example: To use an XSL sheet in an external file
<mulexml:xslt-transformer xsl-file="cities-xslt.xsl" />
In Mule 4:
Mule 4 Example: To use an XSL sheet in an external file
<xml-module:xslt-transform>
<xml-module:xslt>${file:::cities.xslt}</xml-module:xslt>
</xml-module:xslt-transform>
Mule 3 Example: To set context properties
<mulexml:xslt-transformer xsl-file="cities-result-document-xslt.xsl">
<mulexml:context-property key="output_location" value="#[flowVars['outputFile']" />
<mulexml:context-property key="user_id" value="#[flowVars['userId']" />
</mulexml:xslt-transformer>
Mule 4 Example: To set context properties
<xml-module:xslt-transform>
<xml-module:xslt>${file::cities.xslt}</xml-module:xslt>
<xml-module:context-properties>#[{'output_location': vars.outputFile, 'user_id': vars.userId}]</xml-module:context-properties>
</xml-module:xslt-transform>
The XPath extractor no longer supports custom
resultType
parameter. It will now always return a List of Strings with all the matching elements.
Mule 3 Example: To use the XPath extractor
<mule-xml:xpath-extractor-transformer expression="//book" resultType="STRING"/>
Mule 4 Example: To use the XPath extractor
<xml-module:xpath-extract xpath="//book" />
Mule 3 originally had an
xpath()
MEL function. In Mule 3.6, it was deprecated in favor of a new
xpath3()
function. Now, both functions are replaced by a new
XmlModule::xpath()
DataWeave function, which becomes available when the module is added to an application.
Mule 3 Example: Using the xpath3 function
<set-payload value="#[xpath3('//book', payload, 'NODESET')]" />
Mule 3’s
xpath3()
function allowed you to specify the XPath expression and the input value, and it gave different options in terms of the expected output:
BOOLEAN
,
STRING
,
NUMBER
,
NODESET
or
NODE
, where
NODESET
and
NODE
required understanding of Java’s representation of a DOM tree.
The new function also accepts the XPath expression and the input, but differs in these ways:
In Mule 3, a
<mxml:namespace-manager>
is needed to map custom namespaces prefixes:
Mule 3 Example: Using custom namespaces
<mulexml:namespace-manager includeConfigNamespaces="true">
<mulexml:namespace prefix="soap" uri="http://schemas.xmlsoap.org/soap/envelope/"/>
<mulexml:namespace prefix="mule" uri="http://simple.component.mule.org/"/>
</mulexml:namespace-manager>
<flow name="xpathWithNamespace">
<expression-transformer expression="xpath3('/soap:Envelope/soap:Body/mule:echo/mule:echo')" />
</flow>
This approach has the limitation that only one namespace-manager could be used per application. In Mule 4, you can declare as many
namespace-directory
elements as you want, and then reference the one you need on each operation:
Mule 4 Example: Using custom namespaces
<xml-module:namespace-directory name="fullNs">
<xml-module:namespaces>
<xml-module:namespace prefix="soap" uri="http://schemas.xmlsoap.org/soap/envelope/"/>
<xml-module:namespace prefix="mule" uri="http://simple.component.mule.org/"/>
</xml-module:namespaces>
</xml-module:namespace-directory>
<flow name="xpathWithFullNs">
<xml-module:xpath-extract xpath="/soap:Envelope/soap:Body/mule:echo/mule:echo" namespaceDirectory="fullNs"/>
</flow>
Additionally, you could even choose not to declare a 'namespace-directory' and instead just map the namespace inline:
Mule 4 Example: Inline custom namespaces mapping
<flow name="xpathWithFullNs">
<xml-module:xpath-extract xpath="/soap:Envelope/soap:Body/mule:echo/mule:echo">
<xml-module:namespaces>
<xml-module:namespace prefix="soap" uri="http://schemas.xmlsoap.org/soap/envelope/"/>
<xml-module:namespace prefix="mule" uri="http://simple.component.mule.org/"/>
</xml-module:namespaces>
</xml-module:xpath-extract>
</flow>
Depending on the transformation, the elements of that list could be String or some generic Java representation, such as a
Node
.
If the transformation generates only one element, it returns that element.
<mxml:xquery-transformer>
<mxml:context-property key="books" value="#[flowVars['books']]" />
<mxml:context-property key="cities" value="#[flowVars['cities']]" />
<mxml:xquery-text>
<![CDATA[
xquery version "3.0";
declare variable $document external;
declare variable $cities external;
declare variable $books external;
<mixes>
for $b in $books/BOOKLIST/BOOKS/ITEM,
$c in $cities/cities/city
return <mix title="{$b/TITLE/text()}" city="{$c/@name}" />
</mixes>
</mxml:xquery-text>
</mxml:xquery-transformer>
In Mule 4:
Mule 4 Example: Using XQuery transformer
<xml-module:xquery-transform>
<xml-module:xquery>
<![CDATA[
xquery version "3.0";
declare variable $document external;
declare variable $cities external;
declare variable $books external;
<mixes>
for $b in fn:doc($books)/BOOKLIST/BOOKS/ITEM,
$c in fn:doc($cities)/cities/city
return <mix title="{$b/TITLE/text()}" city="{$c/@name}" />
</mixes>
</xml-module:xquery>
<xml-module:context-properties>#[{'books' : vars.books, 'cities': vars.cities}] </xml-module:context-properties>
</xml-module:xquery-transform>
<groupId>org.mule.modules</groupId>
<artifactId>mule-xml-module</artifactId>
<version>1.1.0</version> <!-- or newer -->
<classifier>mule-plugin</classifier>
</dependency>
