CP3024 Lecture 9

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CP3024 Lecture 9

XML revisited, XSL, XSLT, XPath, XSL Formatting Objects

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XML Revision

<?xml version="1.0"?><sweepjoke><harry>Say <quote>Bye Bye </quote>, Sweep </harry>

<sweep> <quote>Bye Bye, Sweep</quote></sweep>

<laughter/></sweepjoke>

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Well formed XML

Begins with XML declarationHas one unique root elementNon-empty elements have closing tagsEmpty elements terminatedTags appear in correct orderAttribute values quoted

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Valid XML

Valid documents are well formedConform to a DTD

– Correct sequence– Correct nesting– Valid attribute values

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Document Type Definition

<?xml version="1.0" standalone="yes"?>

<!DOCTYPE sweepjoke [<!ELEMENT sweepjoke (harry+, sweep, laughter?)>

<!ELEMENT harry (#PCDATA | quote)*><!ELEMENT sweep (#PCDATA | quote)*><!ELEMENT quote (#PCDATA)*><!ELEMENT laughter EMPTY>]>

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Validating Parser

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Not Well Formed

<sweepjoke>

<harry>Say <quote>Bye Bye </quote>, Sweep </harry>

<sweep><quote>Bye Bye, Sweep</sweep></quote>

<laughter/>

</sweepjoke>

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Invalid 1

<sweepjoke>

<quote>Hello</quote>


<sweep><quote>Bye Bye, Sweep</quote></sweep>

<laughter/>

</sweepjoke>

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Invalid 2

<sweepjoke>


<laughter/>

</sweepjoke>

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Invalid 3

<sweepjoke>



<sweep>Hello Sooty</sweep>

<laughter/>

</sweepjoke>

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Is This Valid? 1

<sweepjoke>

<harry>Hello Sooty</harry>



<laughter/>

</sweepjoke>

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Is This Valid? 2

<sweepjoke>



<harry>Hello Sooty</harry>

<laughter/>

</sweepjoke>

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Namespaces in XML

An XML namespace is a collection of names– Identified by a URI reference [RFC2396]– Used in XML documents as element types and

attribute names

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Namespace Definition

<x xmlns:edi='http://ecommerce.org/schema'>



</x>

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Namespace use

<x xmlns:edi='http://ecommerce.org/schema'> 

<edi:price units='Euro'>32.18</edi:price>

</x>

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Structured Publishing

Taken from an example given by Jon Bosak

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XSL

eXtensible Stylesheet LanguageThree parts

– XSLT• Language for transforming XML documents

– XPath• Language for defining parts of an XML document

– XSL Formatting Objects• Vocabulary for formatting XML documents

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XSLT

XSL TransformationsTransforms from an XML source tree to an

XML result treeTypically used to transform XML to

XHTML

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Transformation Process

Use XPath to define parts of the document that match predefined templates

On match, transform source into resultUnmatched parts of the source copied

unmodified to result

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Browser Support

IE 5.0 and 5.5 not 100% compatibleIE 6.0 supports all W3C recommendationsFully supported in Netscape 7.xFully supported in Mozilla 1.3

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Demo XML File

<?xml version = "1.0"?>

<moduleList>

<module no="CP3024">

<name>Web Information Systems</name>

<comment>Easy!</comment>

</module>

<module no="CP2027">

<name>Prog in Java</name>

<comment>Hard</comment>

</module>

</moduleList>

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Required Output

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Untransformed View

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HTML Output

<html><head><title>ModuleList<title></head><body><table border="1" bgcolor="cyan">

<thead><tr>

<th>Module Number</th><th>Name</th><th>Information</th>

</tr></thead>

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HTML Output

<tbody><tr>

<td>CP3024</td><td>Web Information Systems</td><td>Easy!</td>

</tr><tr>

<td>CP2027</td><td>Prog in Java</td><td>Hard</td>

</tr></tbody></table></body></html>

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Style Sheet Declaration

XSL stylesheets are written as XMLFirst line identifies file as XMLSecond line should be:

– <xsl:stylesheet version=“1.0”xmlns:xsl=“http://www.w3.org/1999/XSL/Transform”>

or– <xsl:transform version=“1.0”xmlns:xsl=“http://www.w3.org/1999/XSL/Transform”>

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XSL Template

The <xsl:template> element contains rules to apply when a specified node is matched

The match attribute is used to associate the template with an XML element

E.g. <xsl:template match = "/">

Use of / selects root (whole document)Closes with </xsl:template>

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Example Stylesheet

<?xml version = "1.0"?><xsl:stylesheet version = "1.0" xmlns:xsl = "http://www.w3.org/1999/XSL/Transform"><xsl:template match = "/"> <html><head>

<title>Module List</title></head><body>

<table border = "1" bgcolor = "cyan">

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Example Stylesheet

<thead><tr><th>Module Number</th><th>Name</th><th>Information</th>

</tr></thead>

</table></body></html></xsl:template></xsl:stylesheet>

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Output

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Applying A Stylesheet

<?xml version = "1.0"?><?xml-stylesheet type = "text/xsl" href="moduleTable.xsl" ?><moduleList> <module no="CP3024"> <name>Web Information Systems</name> <comment>Easy!</comment> </module> <module no="CP2027"> <name>Prog in Java</name> <comment>Hard</comment> </module></moduleList>

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XML Tree Representation

n am e com m ent

m od u le

m od u le L ist

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XPath

Identifies parts of an XML documentCan select a node

– moduleSelect direct descendant

– moduleList/moduleSelect any descendant

– moduleList//commentSelect attribute

– @no

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XSL For-Each

Used to select every node of a specified setE.g <xsl:for-each select = "moduleList/module">

The select attribute contains an Xpath expression

It defines the context for the enclosed expressions

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XSL Value-Of

Selects the value of an XML elementAdds it to the outputE.g.

<xsl:value-of select = "name"/>The select attribute contains an Xpath expressionThis determines what is added to the output

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Outputting Elements

<tbody><xsl:for-each select = "moduleList/module"><tr>

<td><xsl:value-of select = "@no"/></td><td><xsl:value-of select = "name"/></td><td><xsl:value-of select = "comment"/></td>

</tr></xsl:for-each>

</tbody>

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Output

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Applying A Filter

Can use for-each statement to select entriesE.g.

<xsl:for-each select = "moduleList/module[@no='CP3024']">

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Sorting Output

Can use xsl:sort

<xsl:for-each select = "moduleList/module"> <xsl:sort select = "name"/> <tr> <td><xsl:value-of select = "@no"/></td> <td><xsl:value-of select = "name"/></td> <td><xsl:value-of select = "comment"/></td> </tr></xsl:for-each>

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XSL:Sort

Select attribute indicates which attribute to sort on

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XSL Formatting Objects

Source: W3C

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XSLT Transform

Source: W3C

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Formatting

Source: W3C

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Final Formatting

Source: W3C

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Summary

XML revisited– Well formed– Valid

XSL– XSLT– XPath– XSL Formatting Objects

CP3024 Lecture 9

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Transcript of CP3024 Lecture 9