Let's break down the concept of an XSLT <template> in a simple way, along with an example:
XML (Extensible Markup Language): XML is a markup language used to store and structure data. It's hierarchical and uses tags to define elements and their relationships.
XSLT (eXtensible Stylesheet Language Transformations): XSLT is a language for transforming XML documents into different formats, such as HTML, XML, or plain text. It uses templates to define how different parts of an XML document should be transformed.
<template> ExplainedIn XSLT, <template> is used to define rules for transforming specific parts of an XML document. Each <template> specifies what should happen when the XSLT processor encounters certain XML elements or conditions.
Let's consider an XML document representing a list of books:
Example
<?xml version="1.0" encoding="UTF-8"?>
<bookstore>
<book category="fiction">
<title>Harry Potter</title>
<author>J.K. Rowling</author>
<year>2005</year>
</book>
<book category="non-fiction">
<title>Introduction to XML</title>
<author>John Doe</author>
<year>2010</year>
</book>
</bookstore>
Suppose we want to transform this XML into an HTML list (<ul>) of book titles only. We can use XSLT <template> to achieve this:
Example
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<!-- Template to match the root element -->
<xsl:template match="/">
<html>
<body>
<h2>Book List</h2>
<ul>
<!-- Apply the 'book' template for each 'book' element -->
<xsl:apply-templates select="bookstore/book"/>
</ul>
</body>
</html>
</xsl:template>
<!-- Template to match 'book' elements -->
<xsl:template match="book">
<li>
<xsl:value-of select="title"/>
</li>
</xsl:template>
</xsl:stylesheet>
XSLT Structure:
<xsl:stylesheet> defines the XSLT document with its version and namespace.xmlns:xsl="http://www.w3.org/1999/XSL/Transform" declares the XSLT namespace.Templates:
<xsl:template match="/">: This template matches the root element of the XML document (/). It defines the structure of the HTML output.
Inside this template, <xsl:apply-templates select="bookstore/book"/> applies the <book> template to each <book> element under <bookstore>.
<xsl:template match="book">: This template matches each <book> element. It specifies that for each <book> encountered, an <li> element should be created in the HTML output containing the value of the <title> element (<xsl:value-of select="title"/>).
When this XSLT transformation is applied to the XML document provided earlier, the output HTML will be:
Example
<html>
<body>
<h2>Book List</h2>
<ul>
<li>Harry Potter</li>
<li>Introduction to XML</li>
</ul>
</body>
</html>
<template> in XSLT specifies rules for transforming XML elements.In the example, we used <template> to define how to transform <book> elements into an HTML list of book titles. This demonstrates the basic usage and power of XSLT templates in transforming XML data into various output formats.