XSLT

Introduction
Extensible Stylesheet Language
Transformations.
XSLT transforms an XML document into
another XML document(generally more
expressive)
XSLT uses XPath to navigate in XML
documents
Itself is an XML document with a root
element stylesheet.

Example-01
<?xml version="1.0" encoding="ISO-8859-1"?>

<?xml-stylesheet type="text/xsl" href="ex1.xsl"?>
<catalog>
<cd>
<title>Empire Burlesque</title>
<artist>Bob Dylan</artist>
<country>USA</country>
<company>Columbia</company>
<price>10.90</price>
<year>1985</year>
</cd>
<cd>
<title>Hide your heart</title>
<artist>Bonnie Tyler</artist>
<country>UK</country>
<company>CBS Records</company>
<price>9.90</price>
<year>1988</year>
</cd>

<cd><title>Greatest Hits</title>
<artist>Dolly Parton</artist>
<company>RCA</company>
<price>9.90</price>
<year>1982</year>
</cd>
<cd><title>Still got the blues</title>
<artist>Gary Moore</artist>
<company>Virgin records</company>
<year>1990</year>
</cd>
<cd><title>Eros</title>
<artist>Eros Ramazzotti</artist>
<country>EU</country>
<company>BMG</company>
<price>9.90</price>
<year>1997</year>
</cd>
<cd><title>Maggie May</title>
<artist>Rod Stewart</artist>
<company>Pickwick</company>
<price>8.50</price>

<cd>
<title>Romanza</title>
<artist>Andrea Bocelli</artist>
<company>Polydor</company>
<year>1996</year>
</cd>
<cd>
<title>Black angel</title>
<artist>Savage Rose</artist>
<company>Mega</company>
<year>1995</year>
</cd>
<cd>
<title>1999 Grammy Nominees</title>
<artist>Many</artist>
<company>Grammy</company>
<year>1999</year>
</cd>
<cd>
<title>For the good times</title>
<artist>Kenny Rogers</artist>
<company>Mucik Master</company>
<price>8.70</price>
<year>1995</year>
</cd>

Using CSS
The information can not be
rearranged(sorting etc.)
Information encoded in attributes can not
be exploited.
Additional structures can not be
introduced.
<?xml-stylesheet type="text/css"
href="ex_css.css"?>

ex_css.css
title{font-size:10;color:red;fontfamily:tahoma}
artist{font-size:24;color:blue}

XSLT
To transform an XML document into
another XML document, or another type of
document that is recognized by a browser,
like HTML and XHTML
Overcomes the limitations of the CSS





can add(remove) elements and attributes to (
from) the output file.
can also rearrange elements
can perform tests and make decisions about
which elements to hide and display

Declaration
Root element is “stylesheet”
Namespace:


http://www.w3.org/1999/XSL/Transform

To use this namespace, it is required to
include the attribute version="1.0".
Example:
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

Linking XSLT to XML Doc.

<?xml-stylesheet type="text/xsl" href=“abc.xsl"?>
<root_element>
….
….
….

</root_element>

Template Element
Template is set of rules
The rules defined by template are applied when the
specified node is matched
Syntax:
 <xsl:template>
Attribute:
 The match attribute is used to associate a template
with an XML element.
 Value of match is an XPath expression.
 Eg: <xsl:template match="/">
For root element


<xsl:template match=" catalog/cd /title">
To select title element

Sample Template
<xsl:template match="title">
Title: <span style="color:blue">
<xsl:value-of select="."/></span>
<br />
</xsl:template>

value-of Element
to extract the value of a selected node and
add it to the output stream of the
transformation
Eg:


<xsl:value-of select="catalog/cd/title"/>

select attribute:



Value is “XPath Expression”
text contents of the node-set returned by the
XPath expression are placed in the result
tree.

for-each Element
Loop construct in XSLT
Eg:
<xsl:for-each select="catalog/cd">
…..
</xsl:for-each>

<xsl:value-of select="title"/>
<xsl:value-of select="artist"/>
</xsl:for-each>
The above piece of code will loop over all
the “cd” elements of “catalog” element.
For each of the cd elements the value of
element “title” and element “artist” will be
placed in the result tree.

ex1.xsl
<xsl:template match="/">
<html> <body>
<h2>My CD Collection</h2>
<table border="1">
<tr bgcolor="#9acd32">
<th>Title</th>
<th>Artist</th>
</tr>
<tr>
<td><xsl:value-of select="title"/></td>
<td><xsl:value-of select="artist"/></td>
</tr>
</xsl:for-each>
</table>
</body> </html>
</xsl:template>
</xsl:stylesheet>

apply-template Element
applies a template to the current element
or to the current element's child nodes.
select attribute:




it will process only the child element that
matches the value of the attribute.
It can be used to specify the order in which
child nodes are processed.

ex_apply.xsl
<xsl:stylesheet version="1.0“ xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<html> <body>
<xsl:apply-templates/>
</body> </html>
</xsl:template>
<xsl:template match="cd">
<p>
<xsl:apply-templates select="title"/>
<xsl:apply-templates select="artist"/>
</p>
</xsl:template>
<xsl:template match="title">
Title: <span style="color:blue">
<xsl:value-of select="."/></span> <br />
</xsl:template>
<xsl:template match="artist">
Artist: <span style="color:#00ff00">
<xsl:value-of select="."/></span> <br />
</xsl:template> </xsl:stylesheet>

sort Element
Sorts the output
Eg:
<xsl:sort select="artist“
order=“ascending”/>
<tr>
</tr>
</xsl:for-each>

The result tree will have cd elements in the
ascending order of element artist.

if Element
put a conditional test against the content
of the XML file
Syntax:
<xsl:if test=“test_expression">
...some output if the expression is true...
</xsl:if>

test attribute:


Specifies the expression to be evaluated.

ex_if.xsl
<html> <body>
<table border="1">
<th>Title</th>
<th>Artist</th>
</tr>
<xsl:if test="price > 10">
<tr>
</tr>
</xsl:if>
</xsl:for-each>
</table>
</body> </html>
</xsl:template>
</xsl:stylesheet>

Multiple Conditional Tests
Apply “when”, “otherwise” and “choose”
element

ex_2.xsl
<xsl:stylesheet version="1.0“ xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<html>
<body>
<table border="1">
<th>Title</th>
<th>Artist</th>
</tr>

Element “element” is used to create an
element.
Attribute “name” is used to specify the
name of the newly created element.
Value of attribute name is an XPath
expression.

Example
<?xml version = "1.0"?>
<sports>
<game title = "cricket">
<id>243</id>
<para> More popular among commonwealth nations. </para>
</game>
<game title = "baseball">
<id>431</id>
<para> More popular in America. </para>
</game>
<game title = "soccer">
<id>123</id>
<para>28 Most popular sport in the world. </para>
</game>
</sports>

stylesheet
<xsl:stylesheet version = "1.0“ xmlns:xsl = "http://www.w3.org/1999/XSL/Transform">
<xsl:template match = "/">
</xsl:template>
<xsl:template match = "sports">
<sports>
</sports>
</xsl:template>
<xsl:template match = "game">
<xsl:element name = "{@title}">
<xsl:attribute name = "id">
<xsl:value-of select = "id"/>
</xsl:attribute>
<comment>
<xsl:value-of select = "para"/>
</comment>
</xsl:element>
</xsl:template>
</xsl:stylesheet>

result.xml
<?xml version = "1.0" encoding = "UTF-8"?>
<sports>
<cricket id = "243">
<comment> More popular among commonwealth nations. </comment>
</cricket>
<baseball id = "431">
<comment> More popular in America. </comment>
</baseball>
<soccer id = "123">
<comment> Most popular sport in the world. </comment>
</soccer>
</sports>

To duplicate nodes from the source tree
into the result tree
Element “copy” is used to produce a
copy of the context node and place it in
the result tree.



Syntax: <xsl:copy>
child nodes and attributes of the current node
are not automatically copied!

Intro.xml
<?xml:stylesheet type = "text/xsl" href = "intro.xsl"?>
<myMessage>
<message>Welcome to XSLT!</message>
</myMessage>

Intro.xsl
<xsl:stylesheet version = "1.0“ xmlns:xsl = “http://www.w3.org/1999/XSL/Transform">
<xsl:template match = "myMessage">
<xsl:copy>
</xsl:copy>
</xsl:template>
<xsl:template match = "message">
<xsl:copy>
How about 'Hi World' for a change!
</xsl:copy>
</xsl:template>
</xsl:stylesheet>

Result.xml
<myMessage>
<message> How about „Hi World‟ for a change! </message>
</myMessage>

copy-of Element
creates a copy of the current node.
Namespace nodes, child nodes, and
attributes of the current node are
automatically copied as well
This element can be used to insert
multiple copies of the same node into
different places in the output.

stylesheet
<xsl:stylesheet version = "1.0”
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match = "myMessage">
<xsl:copy-of select = "."/>
</xsl:template>
</xsl:stylesheet>

result.xml
<myMessage>
<message>Welcome to XSLT!</message>
</myMessage>

import Element
local template has higher precedence than
the imported template

usage2.xsl
<xsl:stylesheet version = "1.0” xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match = "book">
<html>
<body>
</body>
</html>
</xsl:template>
<xsl:template match = "title">
<xsl:value-of select = "."/>
</xsl:template>
<xsl:template match = "author"><br/>
<p>Author:
<xsl:value-of select = "lastName"/>,
<xsl:value-of select = "firstName"/>
</p>
</xsl:template>
<xsl:template match = "*|text()"/>
</xsl:stylesheet>

usage1.xsl
<xsl:stylesheet version = "1.0”
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:import href = "usage2.xsl"/>
<xsl:template match = "title">
<h2>
</h2>
</xsl:template>
</xsl:stylesheet>

Transformed xml
<html>
<body>
<h2>Deitel's XML Primer</h2>
<br>
<p>
Author: Deitel, Paul
</p>
</body>
</html>

include Element
Include element can be used to refer to
another xslt doc.
The attribute “href” specifies the path of
the xsl doc to be included.
The local and the included both the
templates have the same precedence.
If any conflict arises, the template that last
occurs is used.

usage.xsl
<xsl:template match = "/">
<html>
<body>
<xsl:apply-templates select = "book"/>
</body>
</html>
</xsl:template>
<xsl:template match = "book">
<h2> <xsl:value-of select = "title"/> </h2>
</xsl:template>
<xsl:include href = "author.xsl"/>
<xsl:include href = "chapters.xsl"/>
<xsl:template match = "*|text()"/>
</xsl:stylesheet>

author.xsl
<xsl:template match = "author">
<p>Author:
<xsl:value-of select = "lastName"/>,
<xsl:value-of select = "firstName"/>
</p>
</xsl:template>
</xsl:stylesheet>

chapters.xsl
<xsl:template match = "chapters">
Chapters:
<ul>
<xsl:apply-templates select = "chapter"/>
</ul>
</xsl:template>
<xsl:template match = "chapter">
<li>
</li>
</xsl:template>
</xsl:stylesheet>

result.xml
<html>
<body>
<h2>Deitel‟s XML Primer</h2>
<p>Author:
Deitel, Paul</p>
Chapters:
<ul>
<li>Easy XML</li>
<li>XML Elements?</li>
</ul>
</body>
</html>

Variables
variable element is used to declare a local
or global variable.



global variable: declared as a top-level element
local variable: declared within a template

Once variable's value is set,it cannot be
changed or modifued
set value to a variable by the content of the
<xsl:variable> element or by the select
attribute

XSLT

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