Xslt-Modified Slides From Dr Sagiv

8/4/2019 Xslt-Modified Slides From Dr Sagiv

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XSLT eXtensible Stylesheet

Language Transformations

XSLT eXtensible Stylesheet

Language Transformations

Modified Slides from

Dr. Sagiv


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XSL

XSL = eXtensible Stylesheet Language

XSL consists of

XPath (navigation in documents) XSLT (T fortransformations)

XSLFO (FO forformatting objects)

This is a rather complex language for typesetting

(i.e., preparing text for printing) It will not be taught


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Dark Side of the MoonPink Floyd

10.90

Space Oddity

David Bowie

9.90

Aretha: Lady Soul

Aretha Franklin

9.90

An XML document


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XSLT

XSLT

Transforming XML documents into

other XML documents


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XSLT Stylesheet

An XSLT stylesheet is a program thattransforms an XML document intoanother XML document

For example:

Transforming XML to XHTML (HTML thatconforms to XML syntax)

Transforming an XML document to WML (aformat of XML that cellular phones candisplay)


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A Few Things About XSL

XSL is a high-level, functional language

An XSL style sheet is a valid XML

document Valid with respect to the XSL namespace

Therefore, commands in XSL are XSL

elements


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Applying XSLT Stylesheets to

XML Documents There are three ways of applying anXSLT stylesheet to an XML document

Directly applying an XSLTprocessorto theXML document and the XSLT stylesheet

Calling an XSLT processor from within a(Java) program

Adding to the XML document a link to theXSL stylesheet and letting the browser dothe transformation


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Using an XSL Processor

XSL ProcessorXML

document

XSL

stylesheet

Result is

either anXML, HTML

or text

document

java org.apache.xalan.xslt.Process-IN myXmlFile.xml -XSL myXslFile.xsl

-OUT myOutputFile.html

Directly applying the Xalan XSL processor


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Letting a Browser Perform the

Transformation


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How Does XSLT Work?

An XSL stylesheet is a collection oftemplates that are applied to source nodes(i.e., nodes of the given XML document)

Each template has a match attribute thatspecifies to which source nodes thetemplate can be applied

The currentsource node isprocessedbyapplying a template that matches this node

Processing always starts at the root (/)


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Templates

A template has the form

...

The content of a template consists of XML elements and text that are copied to the

result XSL elements that are actually instructions

The pattern syntax is a subset of XPath


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Hello World


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Applying a browser to catalog.xml(catalog.xml has a link to catalog.xsl)

>htmlbodyh1>Hello World/body/html10 are retrieved


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TheElement

Theelement is used inconjunction withandto express test with

multiple conditions There can be manyinside

anelement, but there

should be a singleinside anelement


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Using

To insert a conditional choose against thecontent of the XML file, simply add the

,, andelements to your XSL

document like this:

... some code ...

... some code ....


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Applying Templates Recursively

The following example shows how toapply templates recursively

Generally, it is possible (but not in thisexample) that more than one templatematches the current source node

The specification (www.w3.org/TR/xslt)

describes (Section 5.5) which templateshould be chosen for application


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A CD Catalog


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Title:


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Artist:


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Is Recursive Application of

Templates ReallyN

eeded? The output of the previous example canalso be generated by an XSL stylesheetthat uses only one template that matches

the root (and does not use the element)

However, some tasks can only be done

by applying templates recursively This typically happens when the structure of

the source XML document is not known


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For example

Suppose that we want to write an XSLstylesheet that generates an exact copyof the source XML document

It is rather easy to do it when the structure ofthe source XML document is known

Can we write an XSL stylesheet that does

it for every possible XML document? Yes! (see next slide)


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Identity Transformation

Stylesheet


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TheElement

......

Tells in what format the outputshould be: xml/html/text


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Some Other XSL Elements

The element allows to insertfree text in the output

The element creates a copy

of the current node The element is used to

create a comment node in the result tree

There are more elements and functions:look in the specification!(www.w3.org/TR/xslt)


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My CD Collection

Titles:

, , and


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(contd)

!


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Title

Artist

My CD Collection


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(contd)


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W3Schools Tutorial on XSLT

The W3Schools XSLT Tutorial has(among other things) tables that list all theelements and functions of XSLT

It also has some details aboutimplementations

Some browsers may not implement all

features or may implement some featuresdifferently from the specifications


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Summary

XSLT is a high-level transformationlanguage

Create core output once in XML format(using Servlets, JSP, etc.)

Use XSLT to transform the core output asneeded

Xslt-Modified Slides From Dr Sagiv

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