Java and XSLT

Parameters and Variables

As in other programming languages, it is often desirable to set up a variable whose value is reused in several places throughout a stylesheet. If the title of a book is displayed repeatedly, then it makes sense to store that title in a variable rather than scan through the XML data and locate the title repeatedly. It can also be beneficial to set up a variable once and pass it as a parameter to one or more templates. These templates often use <xsl:if> or <xsl:choose> to produce different content depending on the value of the parameter that was passed.

<xsl:variable>

Variables in XSLT are defined with the <xsl:variable> element and can be global or local. A global variable is defined at the “top-level” of a stylesheet, which means that it is defined outside of any templates as a direct child of the <xsl:stylesheet> element. Top-level variables are visible throughout the entire stylesheet, even in templates that occur before the variable declaration.

The other place to define a variable is inside of a template. These variables are visible only to elements that follow the <xsl:variable> declaration within that template and to their descendants. The code in Example 3-2 showed this form of <xsl:variable> as a mechanism to define the font color.

Defining variables

Variables can be defined in one of three ways:

<xsl:variable name="homePage">index.html</xsl:variable> <xsl:variable name="lastPresident"select="president[position() = last( )]/name"/> <xsl:variable ...