Transforming xml with XSLT

Transforming XML with XSLT
Basics and understanding
Malintha Adikari
Software Engineer

What is XSLT
XSL stands for
EXtensible Stylesheet Language, and is a style
sheet language for XML documents.
XSLT stands for
XSL Transformations

Goals of XSLT
● XSLT is a transformation language for XML
● XSLT is a W3C XML language (the usual XML well-formedness criteria apply)
● XSLT can translate XML into almost anything , e.g.:
○ well-formed HTML (closed tags)
○ any XML, e.g. yours or other XML languages like SVG, X3D
○ non XML, e.g. PDF,ZIP...etc

XML Transformation
XML, XHTML, PDF, Plain text….

Why transforming
o Presentations

XPath Recap..
XPath uses path expressions to navigate in XML documents
Let’s try following example

XPath Recap..
Example 1:
Example 2:

Start with XSLT
<?xml version="1.0"?>
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match="/">
<html>
<body>
……..
</xsl:stylesheet>
● XSLT program is XML document
● XML declaration on top of the file
● A stylesheet root tag with the following
version and namespace attributes (The root
element that declares the document to be an
XSL style sheet is <xsl:stylesheet> or <xsl:
transform>)
● Usually the "xsl" prefix is used for XSLT tags,
but you also can find "xs" or none
● XSLT must be well-formed and valid
● XSLT files usually have the *.xsl extension
and should have the text/xsl or
application/xml mime type
● XSLT uses XPath to find information in an

Associate XML file and XSLT file
You can directly associate a XSLT stylesheet with an XML file by using a so-called
processing instruction
o Most programming languages and all well-know server-side scripting languages include
an XSLT library, so you can tell program to apply an XSLT stylesheet to an XML file
o use a xml-stylesheet instruction if you plan to display XML contents directly in a browser

Example
XML file
<?xml version="1.0" encoding="UTF-8"?>
<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>Greatest Hits</title>
<artist>Dolly Parton</artist>
<company>RCA</company>
<price>9.90</price>
<year>1982</year>
</cd>
</catalog>
Expected output (HTML)

Example
XML file
<?xml-stylesheet type="text/xsl" href="myStyle.xsl"?>
<catalog>
<cd>
<year>1985</year>
</cd>
<cd>
<title>Greatest Hits</title>
<artist>Dolly Parton</artist>
<company>RCA</company>
<price>9.90</price>
<year>1982</year>
</cd>
</catalog>
XSL file (myStyle.xsl)
<?xml version="1.0" encoding="ISO-8859-1"?>
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns="http://www.w3.org/1999/xhtml">
<xsl:output method="html"/>
<html>
<body>
<h2>My CD Collection</h2>
<table border="1">
<tr bgcolor="#9acd32">
<th style="text-align:left">Title</th>
<th style="text-align:left">Artist</th>
</tr>
<xsl:for-each select="catalog/cd">
<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>

How XSLT works
1. The XSLT engine first looks at the XML file and tries to find a XLT rule that will match the root
element
2. The XSLT processor will then "move" inside the rule element and do further processing
o HTML elements (or any other tags) will be copied to the output document
o If an XSLT instruction is found, it will be executed
● XSLT works down "depth-first" the XML tree, i.e.
● it first deals with the rule for the root element,
● then with the first instruction within this rule.
● If the first instruction says "find other rules" it will then apply the first rule found for the first
child element and so forth...
● The rule of the root element is also the last one be finished (since it must deal step-by-step
with everything that is found inside) !!!

XSLT elements
<xsl:template> Element
The <xsl:template> element is used to build templates.The
match attribute is used to associate a template with an XML
element. The value of the match attribute is an XPath
expression
xmlns:xsl="http://www.w3.
org/1999/XSL/Transform">
<xsl:template match="tool">
……….
</xsl:template>
<xsl:template match="paint">
……….
</xsl:template>
<tool>
<field id="prodName">
<value>HAMMER HG2606</value>
</field>
</tool>
<paint>
<value>mypaint001</value>
</field>
</paint>

XSLT elements
<xsl:value-of> Element
The <xsl:value-of> element can be used to extract the value of
an XML element and add it to the output stream of the
transformation
<h1>
<xsl:value-of select="tool/field[@id=’prodName’]/value"/>
</h1>
</xsl:template>
<tool>
</field>
</tool>
<paint>
<value>mypaint001</value>
</field>
</paint>

XSLT elements
<xsl:for-each> Element
The XSL <xsl:for-each> element can be used to select every
XML element of a specified node-set
<html>
<body>
<h2>My Collection</h2>
<table border="1">
<th>Tool</th>
<th>Value</th>
</tr>
<xsl:for-each select="tool">
<tr>
<td><xsl:value-of select="field[@id]"/></td>
<td><xsl:value-of select="field/value"/></td>
</tr>
</xsl:for-each>
</table>
</body>
</html>
</xsl:template>
</xsl:stylesheet>
<tool>
</field>
</tool>
<tool>
<value>myTool</value>
</field>
</tool>

XSLT elements
<xsl:apply-templates> Element
The <xsl:apply-templates> element applies a template to the
current element or to the current element's child nodes.
<html>
<body>
<h2>My CD Collection</h2>
<xsl:apply-templates select=”cd”/>
</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:#ff0000">
<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>
<<?xml version="1.0" encoding="UTF-8"?>
<catalog>
<cd>
<year>1985</year>
</cd>
</catalog>

XSLT elements
The <xsl:if> Element
To put a conditional if test against the content of the XML file,
add an <xsl:if> element to the XSL document.
Syntax
<xsl:if test="expression">
...some output if the expression is true...
</xsl:if>
xmlns:xsl="http://www.w3.
org/1999/XSL/Transform">
…………
<xsl:for-each select="catalog/cd">
<xsl:if test="price>10">
<tr>
<td><xsl:value-of select="title"/></td>
<td><xsl:value-of select="artist"/></td>
</tr>
</xsl:if>
</xsl:for-each>
</xsl:template>
</xsl:stylesheet>

XSLT elements
XSLT <xsl:sort> Element
The <xsl:sort> element is used to sort the output.
For more XSLT elements and functions :
http://www.w3schools.com/xsl/default.asp
XSLT <xsl:choose> Element
The <xsl:choose> element is used in conjunction with
<xsl:when> and <xsl:otherwise> to express multiple
conditional tests.
Syntax
<xsl:choose>
<xsl:when test="expression">
... some output ...
</xsl:when>
<xsl:otherwise>
... some output ....
</xsl:otherwise>
</xsl:choose>

Exercises
1. Download “automation.xml” file from following svn location
https://svn.wso2.org/repos/wso2/carbon/platform/branches/turing/platform-integration/test-automation-framework-2/org.wso2.
carbon.automation.engine/4.3.0/src/main/resources/automation.xml
2. Go to user management section and look at it’s current structure
3. Every “tenant” element has “admin”child and “admin”child has “user” element. You have to get that user element and put it in to
“users” element. New structure should look like this
<tenant domain="wso2.com" key="wso2">
<users>
<user key="admin">
<userName>admin</userName>
<password>admin</password>
</user>
<user key="user1">
<userName>testuser11</userName>
<password>testuser11</password>
</user>
</users>
</tenant>
Other elements remains same as original file. Write the output into new xml file.

Transforming xml with XSLT

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