I have the following template
<h2>one</h2>
<xsl:apply-templates select="one"/>
<h2>two</h2>
<xsl:apply-templates select="two"/>
<h2>three</h2>
<xsl:apply-templates select="three"/>
I would like to only display the headers (one,two,three) if there is at least one member of the corresponding template. How do I check for this?
<xsl:if test="one">
<h2>one</h2>
<xsl:apply-templates select="one"/>
</xsl:if>
<!-- etc -->
Alternatively, you could create a named template,
<xsl:template name="WriteWithHeader">
<xsl:param name="header"/>
<xsl:param name="data"/>
<xsl:if test="$data">
<h2><xsl:value-of select="$header"/></h2>
<xsl:apply-templates select="$data"/>
</xsl:if>
</xsl:template>
and then call as:
<xsl:call-template name="WriteWithHeader">
<xsl:with-param name="header" select="'one'"/>
<xsl:with-param name="data" select="one"/>
</xsl:call-template>
But to be honest, that looks like more work to me... only useful if drawing a header is complex... for a simple <h2>...</h2> I'd be tempted to leave it inline.
If the header title is always the node name, you could simplifiy the template by removing the "$header" arg, and use instead:
<xsl:value-of select="name($header[1])"/>
I like to exercise the functional aspects of XSL which lead me to the following implementation:
<?xml version="1.0" encoding="UTF-8"?>
<!-- test data inlined -->
<test>
<one>Content 1</one>
<two>Content 2</two>
<three>Content 3</three>
<four/>
<special>I'm special!</special>
</test>
<!-- any root since take test content from stylesheet -->
<xsl:template match="/">
<html>
<head>
<title>Header/Content Widget</title>
</head>
<body>
<xsl:apply-templates select="document('')//test/*" mode="header-content-widget"/>
</body>
</html>
</xsl:template>
<!-- default action for header-content -widget is apply header then content views -->
<xsl:template match="*" mode="header-content-widget">
<xsl:apply-templates select="." mode="header-view"/>
<xsl:apply-templates select="." mode="content-view"/>
</xsl:template>
<!-- default header-view places element name in <h2> tag -->
<xsl:template match="*" mode="header-view">
<h2><xsl:value-of select="name()"/></h2>
</xsl:template>
<!-- default header-view when no text content is no-op -->
<xsl:template match="*[not(text())]" mode="header-view"/>
<!-- default content-view is to apply-templates -->
<xsl:template match="*" mode="content-view">
<xsl:apply-templates/>
</xsl:template>
<!-- special content handling -->
<xsl:template match="special" mode="content-view">
<strong><xsl:apply-templates/></strong>
</xsl:template>
Once in the body all elements contained in the test element have header-content-widget applied (in document order).
The default header-content-widget template (matching "*") first applies a header-view then applies a content-view to the current element.
The default header-view template places the current element's name in the h2 tag. The default content-view applies generic processing rules.
When there is no content as judged by the [not(text())] predicate no output for the element occurs.
One off special cases are easily handled.