CODEWITHSUNDEEP
xsltxslt-1.0
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Reputation: 124696

XSLT 1.0 How to update or insert an element after an optional element

This is similar to this question: XSLT-1.0: How to insert an element at a specific position with respect to the parent element, but the answer there doesn't cover the case where tag3 is missing in the input XML

I want to insert or update a tag (say tag4) in the an XML document that looks like the following, except that tag1, tag2, tag3, tag4 and tag5 are all optional.

<Begin>
    <tag1 value="a" />
    <tag2 value="b" />
    <tag3 value="c" />
    <tag4 value="d" />
    <tag5 value="e" />
</Begin>

I.e. the following are sample inputs and outputs

Input:

<Begin>
</Begin>

Output:

<Begin>
    <tag4 value="updated" />
</Begin>

Input:

<Begin>
    <tag4 value="d" />
</Begin>

Output:

<Begin>
    <tag4 value="updated" />
</Begin>

Input:

<Begin>
    <tag1 value="a" />
    <tag5 value="e" />
</Begin>

Output:

<Begin>
    <tag1 value="a" />
    <tag4 value="updated" />
    <tag5 value="e" />
</Begin>

Input:

<Begin>
    <tag1 value="a" />
    <tag2 value="b" />
    <tag5 value="e" />
</Begin>

Output:

<Begin>
    <tag1 value="a" />
    <tag2 value="b" />
    <tag4 value="updated" />
    <tag5 value="e" />
</Begin>

Input:

<Begin>
    <tag1 value="a" />
    <tag2 value="b" />
    <tag3 value="c" />
    <tag5 value="e" />
</Begin>

Output:

<Begin>
    <tag1 value="a" />
    <tag2 value="b" />
    <tag3 value="c" />
    <tag4 value="updated" />
    <tag5 value="e" />
</Begin>

UPDATE

I also want to be able to preserve any attributes that may already be present on the Begin or tag4 element, e.g.:

Input:

<Begin someAttribute="someValue">
    <tag1 value="a" />
    <tag2 value="b" />
    <tag3 value="c" />
    <tag4 value="d" someOtherAttribute="someOtherValue" />
    <tag5 value="e" />
</Begin>

Output:

<Begin someAttribute="someValue">
    <tag1 value="a" />
    <tag2 value="b" />
    <tag3 value="c" />
    <tag4 value="updated" someOtherAttribute="someOtherValue" />
    <tag5 value="e" />
</Begin>

Upvotes: 1

Views: 219

Answers (2)

John Ernst
John Ernst

Reputation: 1235

Give this a try... Trace it through in a debugger to help you figure it out, if needed.

    <xsl:template match="Begin">
      <xsl:copy>
        <!-- Apply any attributes for Begin.  -->
        <xsl:apply-templates select="@*"/>

        <!-- Output the tag* nodes before tag4. -->
        <xsl:apply-templates select="tag1|tag2|tag3"/>

        <xsl:choose>
          <!-- Is there already a tag4? -->
          <xsl:when test="tag4">
            <xsl:apply-templates select="tag4"/>
          </xsl:when>
          <xsl:otherwise>
            <!-- Create tag4 -->
            <tag4 value="updated"/>
          </xsl:otherwise>
        </xsl:choose>

        <!-- Output the tag* nodes after tag4. -->
        <xsl:apply-templates select="tag5"/>
      </xsl:copy>
    </xsl:template>

    <xsl:template match="tag4">
      <xsl:copy>
        <xsl:attribute name="value">d</xsl:attribute>
        <xsl:attribute name="someOtherAttribute">someOtherValue</xsl:attribute>
        <xsl:apply-templates select="node()"/>
      </xsl:copy>
    </xsl:template>

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

Upvotes: 0

Michael Kay
Michael Kay

Reputation: 163272

Try:

<xsl:template match="Begin">
  <Begin>
    <xsl:copy-of select="tag1 | tag2 | tag3"/>
    <tag4 value="updated"/>
    <xsl:copy-of select="tag5"/>
  </Begin>
</xsl:template>

Upvotes: 1

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