XSL - How to tell if element is last in series

Question

I have an XSL template that is selected for execution (below). What I would like to do is be able to tell if I am the last Unit being matched.

  <xsl:template match="Unit[@DeviceType = 'Node']">
    <!-- Am I the last Unit in this section of xml? -->
    <div class="unitchild">
      Node: #<xsl:value-of select="@id"/>
    </div>
  </xsl:template>

Example XML

<Unit DeviceType="QueueMonitor" Master="1" Status="alive" id="7">
    <arbitarytags />
    <Unit DeviceType="Node" Master="0" Status="alive" id="8"/>
    <Unit DeviceType="Node" Master="0" Status="alive" id="88"/>
</Unit>

Answer 1

The currently selected answer is generally incorrect!

<xsl:if test="not(following-sibling::Unit)">

This Will not work with any XML document and any <xsl:apply-templates>

The original question is about the last Unit being matched, not the last sibling! Which is the last Unit being matched depends only on the expression in the select attribute of <xsl:apply-templates>, not on the physical properties of the XML document.

The way to do it:

<xsl:apply-templates select="SomeExpression"/>

then in the template that matches nodes selected by SomeExpression:

<xsl:if test="position() = last()">
. . . . 
</xsl:if>

This checks if the current node is the last in the node-list selected by <xsl:apply-templates>, not that the current node is the last sibling. This answers exactly the original question.

If the question was framed in a different way, asking how to recognize if the last sibling Unit is the current node, then the best solution would be to specify a separate template for this last sibling node:

<xsl:template match="Unit[last()]">
    . . . . 
</xsl:template>

Do note, that in this case there is no need to write any conditional logic inside a template to test if the current node is "the last".

Answer 2

If you want to test whether it is the last Unit element at the same level (with the same parent element), even if there are arbitrary tags before, after, and in-between then this would work:

<xsl:if test="not(following-sibling::Unit)">

However, if you are applying templates for a subset, the last in the document may not be in the set being processed. For that, you can test if the position() = last()

<xsl:if test="position() = last()">