Testing whether a node with particular content exists using xslt - xslt

Question

I am trying to merge the elements from two separate web.xml files using XSLT. For example, if web-1.xml and web-2.xml are being merged, and I'm processing web-1.xml, I want all elements in web-2.xml to be added into the result, except any that already exist in web-1.xml.
In the XSLT sheet, I have loaded the document whose servlet's are to be merged into the other document using:
<xsl:variable name="jandy" select="document('web-2.xml')"/>
I then have the following rule:
<xsl:template match="webapp:web-app">
<xsl:copy>
<!-- Copy all of the existing content from the document being processed -->
<xsl:apply-templates/>
<!-- Merge any <servlet> elements that don't already exist into the result -->
<xsl:for-each select="$jandy/webapp:web-app/webapp:servlet">
<xsl:variable name="servlet-name"><xsl:value-of select="webapp:servlet-name"/></xsl:variable>
<xsl:if test="not(/webapp:web-app/webapp:servlet/webapp:servlet-name[text() = $servlet-name])">
<xsl:copy-of select="."/>
</xsl:if>
</xsl:for-each>
</xsl:copy>
</xsl:template>
The problem I'm having is getting the test in the if correct. With the above code, the test always evaluates to false, whether a servlet-name element with the given node exists or not. I have tried all kinds of different tests but with no luck.
The relevant files are available at http://www.cs.hope.edu/~mcfall/stackoverflow/web-1.xml, and http://www.cs.hope.edu/~mcfall/stackoverflow/transform.xslt (the second web-2.xml is there as well, but StackOverflow won't let me post three links).

Answer 1

provide an anchor for the first document, just before the for-each loop:
<xsl:variable name="var" select="."/>
then, use it in your if:
<xsl:if test="not($var/webapp:servlet/webapp:servlet-name[text() = $servlet-name])">

Answer 2

Your template matches XPATH webapp:webapp from web-1.xml and
you are refencing absolute XPATH if your xsl:if condition: /webapp:web-app/webapp:servlet/webapp:servlet-name[text() = $servlet-name]. Try to do it using relative XPATH:
<xsl:if test="not(webapp:servlet/webapp:servlet-name[text() = $servlet-name])">
<xsl:copy-of select="."/>
</xsl:if>
I haven't checked it, so you have to give it a try.
Also, it would be easier if you could provide web-1.xml and web-2.xml files.
EDIT
The following XSLT merges two files - the only problem appears when there are sections of the same type (like listener) in two places of the input XML.
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:webapp="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://java.sun.com/xml/ns/javaee"
xpath-default-namespace="http://java.sun.com/xml/ns/javaee">
<xsl:output indent="yes"/>
<xsl:variable name="jandy" select="document('web-2.xml')"/>
<xsl:template match="/">
<xsl:element name="web-app">
<xsl:for-each select="webapp:web-app/*[(name() != preceding-sibling::node()[1]/name()) or (position() = 1)]">
<xsl:variable name="nodeName" select="./name()"/>
<xsl:variable name="web1" as="node()*">
<xsl:sequence select="/webapp:web-app/*[name()=$nodeName]"/>
</xsl:variable>
<xsl:variable name="web2" as="node()*">
<xsl:sequence select="$jandy/webapp:web-app/*[name() = $nodeName]"/>
</xsl:variable>
<xsl:copy-of select="$web1" copy-namespaces="no"/>
<xsl:for-each select="$web2">
<xsl:variable name="text" select="./*[1]/text()"/>
<xsl:if test="count($web1[*[1]/text() = $text]) = 0">
<xsl:copy-of select="." copy-namespaces="no"/>
</xsl:if>
</xsl:for-each>
</xsl:for-each>
</xsl:element>
</xsl:template>
</xsl:stylesheet>