Removing Elements from an XML Document, XSLT, and JAXB

Question

This question is a continuation of my previous question: Creating a valid XSD open using <all> and <any> Elements

Given that I have a Java string containing an XML document of the following form:

<TRADE> <TIME>12:12</TIME> <MJELLO>12345</MJELLO> <OPTIONAL>12:12</OPTIONAL> <DATE>25-10-2011</DATE> <HELLO>hello should be ignored</HELLO> </TRADE> 

How to use XSLT or the like (in Java using JAXB) to remove all elements not contained in a set of elements. In the above example, I'm only interested in (TIME, OPTIONAL, DATE), so I would like to convert it to:

 <TRADE> <TIME>12:12</TIME> <OPTIONAL>12:12</OPTIONAL> <DATE>25-10-2011</DATE> </TRADE> 

The order of the elements is not fixed.

Answer 1

This conversion is:

 <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"> <xsl:output omit-xml-declaration="yes" indent="yes"/> <xsl:strip-space elements="*"/> <xsl:param name="pNames" select="'|TIME|OPTIONAL|DATE|'"/> <xsl:output omit-xml-declaration="yes" indent="yes"/> <xsl:strip-space elements="*"/> <xsl:template match="node()|@*" name="identity"> <xsl:copy> <xsl:apply-templates select="node()|@*"/> </xsl:copy> </xsl:template> <xsl:template match="*/*"> <xsl:if test="contains($pNames, concat('|', name(), '|'))"> <xsl:call-template name="identity"/> </xsl:if> </xsl:template> </xsl:stylesheet> 

when applied to the provided XML document:

 <TRADE> <TIME>12:12</TIME> <MJELLO>12345</MJELLO> <OPTIONAL>12:12</OPTIONAL> <DATE>25-10-2011</DATE> <HELLO>hello should be ignored</HELLO> </TRADE> 

creates the desired, correct result:

 <TRADE> <TIME>12:12</TIME> <OPTIONAL>12:12</OPTIONAL> <DATE>25-10-2011</DATE> </TRADE> 

Explanation

• An identity rule (template) copies each node "as is".

• An identification rule is overridden by a template that matches any element that is not the top element of the document . Inside the template, a check is performed if the name of the matching element is one of the names specified in the external parameter $pNames in the line of dereferenced lines with null names.

• Refer to your XSLT processor documentation on how to pass a parameter to a conversion - this is implementation dependent and differs from processor to processor.

Answer 2

I haven't tried it yet, but maybe the javax.xml.tranform package might help:

http://download.oracle.com/javase/6/docs/api/javax/xml/transform/package-summary.html

Answer 3

JAXB and XSLT

JAXB integrates very well with XSLT for example:

• How to make jaxb ignore certain data during unmarshalling

Another question

According to your previous question (see link below), the conversion is really not necessary, because JAXB will simply ignore attributes and elements that do not appear in fields / properties in the domain object.

• Creating a valid XSD open using <all> and <any> Elements