Update the text of an element with XSLT based on p

Question

I'm trying to do something that seems like it should be very simple, but I can't get it working, and I can't seem to find any examples that don't involve lots of irrelevant things. I want to update the text content of a specific xml tag to a specific value (passed in as a parameter, this XSLT will be used from ant). A simple example :

I want to transform

<foo>
  <bar>
    baz
  </bar>
</foo>

To

<foo>
    <bar>
        something different
    </bar>
</foo>

This is the stylesheet that I tried, which results in just the tags, no text at all

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
    <!-- identity transformation, to keep everything unchanged except for the stuff we want to change -->
    <!-- Whenever you match any node or any attribute -->
    <xsl:template match="node()|@*">
        <!-- Copy the current node -->
        <xsl:copy>
            <!-- Including any attributes it has and any child nodes -->
            <xsl:apply-templates select="@*|node()"/>
        </xsl:copy>
    </xsl:template>

    <!-- change the text of the bar node, in the real template the value won't be specified inline -->
    <xsl:template match="/foo/bar/">
        <xsl:param name="baz" value="something different"/>
            <xsl:value-of select="$baz"/>
    </xsl:template>
</xsl:stylesheet>

Thanks in advance!

Answer 1

<xsl:stylesheet 
  xmlns:xsl="http://www.w3.org/1999/XSL/Transform" 
  version="1.0">
<xsl:output indent="yes" encoding="UTF-8" method="xml"/>
<xsl:param name="param-from-ant" as="xs:string"/>

<xsl:template match="node()|@*">
 <xsl:copy>
  <xsl:apply-templates select="@*|node()"/>
 </xsl:copy>
</xsl:template>

<xsl:template match="/foo/bar">
 <xsl:value-of select="$param-from-ant"/>
</xsl:template>
</xsl:stylesheet>

Answer 2

A slightly different approach:

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

  <xsl:param name="replace"/>

  <xsl:template match="node()|@*">
    <xsl:choose>
      <xsl:when test="text() and name(..)='bar' and name(../..)='foo'">
        <xsl:value-of select="$replace"/>
      </xsl:when>
      <xsl:otherwise>
        <xsl:copy>
          <xsl:apply-templates select="@*|node()"/>
        </xsl:copy>
      </xsl:otherwise>
    </xsl:choose>
  </xsl:template>

Answer 3

There are a number of problems with the provided code which lead to compile-time errors:

<xsl:template match="/foo/bar/"> 
    <xsl:param name="baz" value="something different"/> 
        <xsl:value-of select="$baz"/> 
</xsl:template>

1. The match pattern specified on this template is syntactically illegal -- an XPath expression cannot end with the / character.

2. xsl:param cannot have an unknown attribute such as value

Solution:

<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="pReplacement" select="'Something Different'"/>

 <xsl:template match="node()|@*">
     <xsl:copy>
       <xsl:apply-templates select="node()|@*"/>
     </xsl:copy>
 </xsl:template>

 <xsl:template match="foo/bar/text()">
  <xsl:value-of select="$pReplacement"/>
 </xsl:template>
</xsl:stylesheet>

When this transformation is applied on the provided XML document:

<foo>
  <bar>
    baz
  </bar>
</foo>

the wanted, correct result is produced:

<foo>
   <bar>Something Different</bar>
</foo>