1 Extensible Extensible Stylesheet Language Stylesheet Language (XSL) (XSL)
Jan 07, 2016
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Extensible Stylesheet Extensible Stylesheet Language (XSL)Language (XSL)
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The XSL StandardThe XSL Standard
XSL consists of 3 parts:
• XPathXPath (navigation in documents)
• XSLTXSLT (transformation of documents)
• XSLFOXSLFO (FO for formatting objects)
- A rather complex language for typesetting
(e.g., for preparing text for printing)- It will not be taught
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XML Path LanguageXML Path Language(XPath)(XPath)
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XML example revisited: XML example revisited:
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<?xml version="1.0"?>
<!DOCTYPE countries SYSTEM "world.dtd">
<countries>
<country continent="&as;">
<name>Israel</name>
<population year="2001">6199008</population>
<city capital="yes"><name>Jerusalem</name></city>
<city><name>Ashdod</name></city>
</country>
<country continent="&eu;">
<name>France</name>
<population year="2004">60424213</population>
</country>
</countries> world.xmlworld.xml
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The XML DOM ModelThe XML DOM Model
country
Asia Israel 6199008
name populationcontinent
AshdodJerusalem
namename
2001
year
countries
city
no
capital
yes
capital
city
document rootThe root is implicit(Does not appear in the
text of the XML document)
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<!ELEMENT countries (country*)> <!ELEMENT country (name,population?,city*)> <!ATTLIST country continent CDATA #REQUIRED> <!ELEMENT name (#PCDATA)> <!ELEMENT city (name)><!ATTLIST city capital (yes|no) "no"> <!ELEMENT population (#PCDATA)> <!ATTLIST population year CDATA #IMPLIED> <!ENTITY eu "Europe"> <!ENTITY as "Asia"><!ENTITY af "Africa"><!ENTITY am "America"><!ENTITY au "Australia"> world.dtdworld.dtd
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The XPath LanguageThe XPath Language
• XPath expressions are used for addressing elements (nodes) of an XML document
• Used in XSLT (next subject today) and in XQuery (a query language for XML)
• The syntax resembles that of the Unix file system- But the semantics have some substantial differences
/countries/country[population>10000000]
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<?xml version="1.0"?>
<!DOCTYPE countries SYSTEM "world.dtd">
<countries>
<country continent="&as;">
<name>Israel</name>
<population year="2001">6199008</population>
<city capital="yes"><name>Jerusalem</name></city>
<city><name>Ashdod</name></city>
</country>
<country continent="&eu;">
<name>France</name>
<population year="2004">60424213</population>
</country>
</countries>
world.xmlworld.xml/countries/country[population>10000000]
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<?xml version="1.0"?>
<!DOCTYPE countries SYSTEM "world.dtd">
<countries>
<country continent="&as;">
<name>Israel</name>
<population year="2001">6199008</population>
<city capital="yes"><name>Jerusalem</name></city>
<city><name>Ashdod</name></city>
</country>
<country continent="&eu;">
<name>France</name>
<population year="2004">60424213</population>
</country>
</countries>
world.xmlworld.xml//country[@continent="Asia"]/city
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XPath ExpressionsXPath Expressions
• An XPath expression (or just XPath for short) matches paths in the XML tree
• An absolute path begins with the root of the document- Starts with "/" (or "//")- For example, /countries/country/city, //city
• A relative path begins with a context node that is defined by the application that uses the XPath- For example, city/name, or ./name
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Applying XPath to XMLApplying XPath to XML
• Formally, the result of applying an XPath e to an XML document (or a context node in the
document) is the list of all nodes n in the document, such that e matches the path from the root (or the context node) to n
• The order in the list is defined by the order of the nodes in the document
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XPath Steps and Axis XPath Steps and Axis
• An XPath describes a sequence of steps that together characterize a path
• A step is defined by an axis that specifies a tree relationship between nodes- More particularly, the axis describes how to get from the
current node to the next one- For example, parent-child, child-parent, ancestor-
descendant, etc.
• Consecutive steps are separated by /
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Child AxisChild Axis
• A child axis has the simple form tagName - Go to an element child with the tag tagName
• For example, - /tagName matches the tagName child of root- city/name - /countries/country/city
• The child axis * matches every tag- For example: /*/*/city, */name
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Child-Axis ExamplesChild-Axis Examples
country
Asia Israel 6199008
name populationcontinent
AshdodJerusalem
namename
2001
year
countries
city
no
capital
yes
capital
city
document root
/countries
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Child-Axis ExamplesChild-Axis Examples
country
Asia Israel 6199008
name populationcontinent
AshdodJerusalem
namename
2001
year
countries
city
no
capital
yes
capital
city
document root
/countries/country/city
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Child-Axis ExamplesChild-Axis Examples
country
Asia Israel 6199008
name populationcontinent
AshdodJerusalem
namename
2001
year
countries
city
no
capital
yes
capital
city
document root
city/name
Context
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Child-Axis ExamplesChild-Axis Examples
country
Asia Israel 6199008
name populationcontinent
AshdodJerusalem
namename
2001
year
countries
city
no
capital
yes
capital
city
document root
/*/country/*
An attribute is not an element child!
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Self and Descendant-or-Self Self and Descendant-or-Self
• The self axis “.” denotes the identity relationship - That is, the step “remain in the current node”- /countries/country/. ≡ /countries/country- country/./city ≡ country/city
• The descendant-or-self axis means: either stay in the current node or go to some descendant of the current node - descendant-or-self:node(),
• // is a shotrcut notation for /descendant-or-self:node()/- For example, country//name
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Descendant ExamplesDescendant Examples
country
Asia Israel 6199008
name populationcontinent
AshdodJerusalem
namename
2001
year
countries
city
no
capital
yes
capital
city
document root
/countries//name
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Descendant ExamplesDescendant Examples
country
Asia Israel 6199008
name populationcontinent
AshdodJerusalem
namename
2001
year
countries
city
no
capital
yes
capital
city
document root
.//*
Context
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Other Axis TypesOther Axis Types
• The parent axis “..” denotes the parent relationship- That is, the step “go to the parent of the current node”- For example, //name/../population
• XPath has more axis types (denoted by a different syntax from the ones shown earlier):- descendant- ancestor- ancestor-or-self- following-sibling- preceding-sibling- …
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Referring AttributesReferring Attributes
• The attribute axis is denoted @attName - That is, “go to the attribute attName of the current node”
• The operator @* matches every attribute
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Attribute ExamplesAttribute Examples
country
Asia Israel 6199008
name populationcontinent
AshdodJerusalem
namename
2001
year
countries
city
no
capital
yes
capital
city
document root
//country/@continent
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Attribute ExamplesAttribute Examples
country
Asia Israel 6199008
name populationcontinent
AshdodJerusalem
namename
2001
year
countries
city
no
capital
yes
capital
city
document root
@continent
Context
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Attribute ExamplesAttribute Examples
country
Asia Israel 6199008
name populationcontinent
AshdodJerusalem
namename
2001
year
countries
city
no
capital
yes
capital
city
document root
//@*
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XPath PredicatesXPath Predicates
• Predicates in XPath are used for filtering out steps
• For example, //city[@captial="yes"] will match only capital cities
• Formally, given a predicate [PExpr], the expression PExpr is transformed into a Boolean value and the step is taken only if this value is true- The node reached in the last step is the context node
• XPath has a rather rich language for predicate expressions; we only demonstrate common ones
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<?xml version="1.0"?>
<!DOCTYPE countries SYSTEM "world.dtd">
<countries>
<country continent="&as;">
<name>Israel</name>
<population year="2001">6199008</population>
<city capital="yes"><name>Jerusalem</name></city>
<city><name>Ashdod</name></city>
</country>
<country continent="&eu;">
<name>France</name>
<population year="2004">60424213</population>
</country>
</countries>
world.xmlworld.xml//country[./population>10000000]
• The XPath ./population is transformed into a number by taking its embedded text
• The XPath ./population is relative to the current node (i.e., country) in the path
• Equivalent to //country[population>10000000]
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<?xml version="1.0"?>
<!DOCTYPE countries SYSTEM "world.dtd">
<countries>
<country continent="&as;">
<name>Israel</name>
<population year="2001">6199008</population>
<city capital="yes"><name>Jerusalem</name></city>
<city><name>Ashdod</name></city>
</country>
<country continent="&eu;">
<name>France</name>
<population year="2004">60424213</population>
</country>
</countries>
world.xmlworld.xml//country[.//city]
An XPath evaluates to true if and only if its result is not empty
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<?xml version="1.0"?>
<!DOCTYPE countries SYSTEM "world.dtd">
<countries>
<country continent="&as;">
<name>Israel</name>
<population year="2001">6199008</population>
<city capital="yes"><name>Jerusalem</name></city>
<city><name>Ashdod</name></city>
</country>
<country continent="&eu;">
<name>France</name>
<population year="2004">60424213</population>
</country>
</countries>
world.xmlworld.xml//country[//city]
Why?
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<?xml version="1.0"?>
<!DOCTYPE countries SYSTEM "world.dtd">
<countries>
<country continent="&as;">
<name>Israel</name>
<population year="2001">6199008</population>
<city capital="yes"><name>Jerusalem</name></city>
<city><name>Ashdod</name></city>
</country>
<country continent="&eu;">
<name>France</name>
<population year="2004">60424213</population>
</country>
</countries>
world.xmlworld.xml//country[population[.>3000000 and @year>2003]]
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<?xml version="1.0"?>
<!DOCTYPE countries SYSTEM "world.dtd">
<countries>
<country continent="&as;">
<name>Israel</name>
<population year="2001">6199008</population>
<city capital="yes"><name>Jerusalem</name></city>
<city><name>Ashdod</name></city>
</country>
<country continent="&eu;">
<name>France</name>
<population year="2004">60424213</population>
</country>
</countries>
world.xmlworld.xml
//country[name="Israel" or name="Spain"]/population
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<?xml version="1.0"?>
<!DOCTYPE countries SYSTEM "world.dtd">
<countries>
<country continent="&as;">
<name>Israel</name>
<population year="2001">6199008</population>
<city capital="yes"><name>Jerusalem</name></city>
<city><name>Ashdod</name></city>
</country>
<country continent="&eu;">
<name>France</name>
<population year="2004">60424213</population>
</country>
</countries>
world.xmlworld.xml//country/city[2]
• A number acts as an index
• That is, the number n evaluates to true if n is the position of the node among all those reached in the last step (i.e., city)
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FunctionsFunctions
• Inside XPath predicates, you can use a set of predefined functions
• Here are some examples:- last() – returns the number of nodes obtained from
the last axis step- position() – returns the position of the node in the list
of nodes satisfying the last axis step- name() – returns the name (tag) of the current node- count(XPath) – returns the number of nodes
satisfying XPath
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<?xml version="1.0"?>
<!DOCTYPE countries SYSTEM "world.dtd">
<countries>
<country continent="&as;">
<name>Israel</name>
<population year="2001">6199008</population>
<city capital="yes"><name>Jerusalem</name></city>
<city><name>Ashdod</name></city>
</country>
<country continent="&eu;">
<name>France</name>
<population year="2004">60424213</population>
</country>
</countries>
world.xmlworld.xml//country/city[last()]
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<?xml version="1.0"?>
<!DOCTYPE countries SYSTEM "world.dtd">
<countries>
<country continent="&as;">
<name>Israel</name>
<population year="2001">6199008</population>
<city capital="yes"><name>Jerusalem</name></city>
<city><name>Ashdod</name></city>
</country>
<country continent="&eu;">
<name>France</name>
<population year="2004">60424213</population>
</country>
</countries>
world.xmlworld.xml//city[position()<2]
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<?xml version="1.0"?>
<!DOCTYPE countries SYSTEM "world.dtd">
<countries>
<country continent="&as;">
<name>Israel</name>
<population year="2001">6199008</population>
<city capital="yes"><name>Jerusalem</name></city>
<city><name>Ashdod</name></city>
</country>
<country continent="&eu;">
<name>France</name>
<population year="2004">60424213</population>
</country>
</countries>
world.xmlworld.xml//*[name()="city" or name()="country"]
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<?xml version="1.0"?>
<!DOCTYPE countries SYSTEM "world.dtd">
<countries>
<country continent="&as;">
<name>Israel</name>
<population year="2001">6199008</population>
<city capital="yes"><name>Jerusalem</name></city>
<city><name>Ashdod</name></city>
</country>
<country continent="&eu;">
<name>France</name>
<population year="2004">60424213</population>
</country>
</countries>
world.xmlworld.xml//*[starts-with(name(),“c")]
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<?xml version="1.0"?>
<!DOCTYPE countries SYSTEM "world.dtd">
<countries>
<country continent="&as;">
<name>Israel</name>
<population year="2001">6199008</population>
<city capital="yes"><name>Jerusalem</name></city>
<city><name>Ashdod</name></city>
</country>
<country continent="&eu;">
<name>France</name>
<population year="2004">60424213</population>
</country>
</countries>
world.xmlworld.xml//country[count(./city)>=1]
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Final RemarksFinal Remarks
• The syntax of XPath that was presented here is the abbreviated syntax
• For example, city/../@name is an abbrv. of
child::city/parent::node()
/attribute::name
• More details on XPath:- XPath tutorial in W3Schools- XPath W3C Recommendation
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XSL Transformations XSL Transformations (XSLT)(XSLT)
An Example:
Useful Links in the DBI site
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XSLTXSLT
• XSLT is a language for transforming XML documents into other XML documents- For example, XHTML, WML- Can also transform XML to general text documents, e.g.,
SQL programs
• An XSLT program is itself an XML document (called an XSL stylesheet) that describes the transformation process for input documents
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Text
WML
DTD
XSLT ProcessorsXSLT Processors
XML
XSL
XSLT Processor
XHTML
44Web Page
Presentation
Doc. Structure
Data
Web Pages Web Pages –– The Whole Picture The Whole Picture
XMLXML
XSLXSL
XHTMLXHTML
Style
KnowledgeKnowledge
CSSCSS
DynamicsJavaScriptJavaScript
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<?xml version="1.0" encoding="ISO-8859-1"?><catalog> <cd country="UK"> <title>Dark Side of the Moon</title> <artist>Pink Floyd</artist> <price>10.90</price> </cd> <cd country="UK"> <title>Space Oddity</title> <artist>David Bowie</artist> <price>9.90</price> </cd> <cd country="USA"> <title>Aretha: Lady Soul</title> <artist>Aretha Franklin</artist> <price>9.90</price> </cd> </catalog>
catalog.xmlcatalog.xml
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<?xml version="1.0" encoding="ISO-8859-1"?>
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match="/">
<html>
<head><title>cd catalog</title></head>
<body><h1>This is a cd catalog!</h1></body>
</html>
</xsl:template>
</xsl:stylesheet>
Valid XML! Commands are XML elements with the namespace xslIncludes XHTML
elements
catalog.xslcatalog.xsl
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Applying XSL Stylesheets to XMLApplying XSL Stylesheets to XML
There are several ways of applying an XSL stylesheet to an XML document:
- Directly applying an XSLT processor to the XML document and the XSL stylesheet
- Calling an XSLT processor from within a program
- Adding to the XML document a link to the XSL stylesheet and letting the browser do the transformation
• The resulting XHTML document is shown, not the original XML
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Processing XSL in JavaProcessing XSL in Java
You can use the XALAN package of Apache in order to process XSL transformations
java org.apache.xalan.xslt.Process -IN myXmlFile.xml -XSL myXslFile.xsl -OUT myOutputFile.html
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How Does XSLT Work?How Does XSLT Work?• An XSL stylesheet is a collection of templates that are
applied to source nodes (i.e., nodes of the given XML)
• Each template has a match attribute that specifies to which source nodes the template can be applied
• Each source node has a template that matches it
• The current source node is processed by applying a template that matches this node
• When processing a node, it is possible to recursively process other nodes, e.g., the children of the current node
• Finally, the XSLT processor simply processes the root node of the document (that matches /)
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TemplatesTemplates
• A template has the form <xsl:template match="pattern">
...
</xsl:template>
• The content of a template consists of - XML elements (e.g., XHTML) and text that are copied
to the result- XSL elements (<xsl:…>) that are actually instructions
• The syntax for the pattern is a subset of XPath
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<?xml version="1.0" encoding="ISO-8859-1"?>
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match="/">
<html>
<head><title>cd catalog</title></head>
<body><h1>This is a cd catalog!</h1></body>
</html>
</xsl:template>
</xsl:stylesheet>
catalog1.xsl
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<?xml version="1.0" encoding="ISO-8859-1"?><?xml-stylesheet type="text/xsl"
href="catalog1.xsl"?><catalog> <cd country="UK"> <title>Dark Side of the Moon</title> <artist>Pink Floyd</artist> <price>10.90</price> </cd> <cd country="UK"> <title>Space Oddity</title> <artist>David Bowie</artist> <price>9.90</price> </cd> <cd country="USA"> <title>Aretha: Lady Soul</title> <artist>Aretha Franklin</artist> <price>9.90</price> </cd> </catalog>
catalog1.xml
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The ResultThe Result
<html>
<head>
<META http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>cd catalog</title>
</head>
<body>
<h1>This is a cd catalog!</h1>
</body>
</html>
Implicitly added to <head>
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Examples of Match AttributesExamples of Match Attributes• match="cd",
- All elements with tag name cd
• match="//cd", match="/catalog/cd/artist"- All matches of the absolute XPath
• match="cd/artist"- All artist nodes that have a cd parent
• match="catalog//artist"- All artist nodes that have a catalog ancestor
• match="cd[@country='UK']/artist"
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• Processing starts by applying a temp. to the root - If no specified template matches the root, then one is
inserted by default (see the next slide)
• You must specify explicitly whether templates should be applied to descendants of a node
• Done using the instruction:<xsl:apply-templates select="xpath"/>
- In xpath, cur. processed node is the context node
• Without the select attribute, this instruction processes all the children of the current node (including text nodes)
<xsl:apply-templates><xsl:apply-templates>
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Default TemplatesDefault Templates
• XSL provides implicit built-in templates that match every element and text nodes
• Templates we write always override these built-in templates (when they match)
<xsl:template match="/|*"><xsl:apply-templates/>
</xsl:template>
<xsl:template match="text()|@*"><xsl:value-of select="."/>
</xsl:template>
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<?xml version="1.0" encoding="ISO-8859-1"?>
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
</xsl:stylesheet>
Dark Side of the Moon
Pink Floyd
10.90
Space Oddity
David Bowie
9.90
…
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<?xml version="1.0" encoding="ISO-8859-1"?>
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match="cd">
<h2>A cd!</h2>
</xsl:template>
</xsl:stylesheet>
<h2>A cd!</h2>
<h2>A cd!</h2>
<h2>A cd!</h2>
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<h2>A cd!</h2>
<h2>A cd!</h2>
Aretha: Lady Soul
Aretha Franklin
9.90
<?xml version="1.0" encoding="ISO-8859-1"?>
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match="cd[@country='UK']">
<h2>A cd!</h2></xsl:template>
</xsl:stylesheet>
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<h2>An artist!</h2>
<h2>An artist!</h2>
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match="/">
<xsl:apply-templates
select="catalog/cd[@country='UK']/artist"/>
</xsl:template>
<xsl:template match="artist">
<h2>An artist!</h2>
</xsl:template>
</xsl:stylesheet>
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<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match="/">
<xsl:apply-templates
select="cd[@country='UK']/artist"/>
</xsl:template>
<xsl:template match="artist">
<h2>An artist!</h2>
</xsl:template>
</xsl:stylesheet>
Why?
62
Frequently Used Elements of XSLFrequently Used Elements of XSL
• <xsl:value-of select="xpath"/>- This element extracts the value of a node from the
nodelist located by xpath
• <xsl:for-each select="xpath"/>- This element loops over all the nodes in the node list
located by xpath
• <xsl:if test="cond"/>,
<xsl:if test="xpath"/>, etc.- This element is for conditional processing
63
<?xml version="1.0" encoding="ISO-8859-1"?>
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match="/">
<html><head><title>cd catalog</title></head>
<body>
<h1>CD catalog</h1>
<ul>
<xsl:for-each select="catalog/cd">
<li><xsl:value-of select="title"/>
[<xsl:value-of select="artist"/>]</li>
</xsl:for-each>
</ul></body></html>
</xsl:template>
</xsl:stylesheet>
Currently selected element is the context node
Example 1
catalog2.xsl
view catalog2.xm
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64
<?xml version="1.0" encoding="ISO-8859-1"?>
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match="/">
<html><head><title>cd catalog</title></head>
<body>
<h1>CD catalog</h1>
<ul>
<xsl:for-each select="catalog/cd">
<li><xsl:apply-templates select="."/></li>
</xsl:for-each>
</ul></body></html>
</xsl:template>
Example 2
catalog3.xsl
65
<xsl:template match="cd">
<b><xsl:value-of select="artist"/></b>:
<xsl:value-of select="title"/>
<xsl:if test="price<10">
(<em>now on sale: $<xsl:value-of select="price"/>
</em>)
</xsl:if>
</xsl:template>
</xsl:stylesheet>
Example 2 (cont.)
Entities replace characters
price>10 → price<10
catalog3.xsl
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66
Example 3
<xsl:choose>:
Switch syntax for conditions
<xsl:choose>
<xsl:when test="price < 9">
<em>Special price!</em>
</xsl:when>
<xsl:when test="price>9 and price<=10">
<i>Good price!</i>
</xsl:when>
<xsl:otherwise>
(Normal price.)
</xsl:otherwise>
</xsl:choose>
67
The The <xsl:sort><xsl:sort> Element Element
• The <xsl:sort> element is used to sort the list of nodes that are looped over by the <xsl:for-each> element
• Thus, the <xsl:sort> must appear inside the <xsl:for-each> element
• The looping is done in sorted order
68
<?xml version="1.0" encoding="ISO-8859-1"?>
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match="/">
<html><head><title>cd catalog</title></head>
<body>
<h1>CD catalog</h1>
<ul>
<xsl:for-each select="catalog/cd">
<xsl:sort select="title"/>
<li><xsl:value-of select="title"/></li>
</xsl:for-each>
</ul></body></html>
</xsl:template>
</xsl:stylesheet>
CDs are iterated in ascending order of the titles
catalog4.xsl
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69
Setting Values in AttributesSetting Values in Attributes
• The <xsl:value-of> element cannot be used within an attribute value
• However, we can insert expressions into attribute values, by putting the expression inside curly braces ({})
• Alternatively, we can use <xsl:element> in order to construct XML elements
70
An ExampleAn Example
• In the following example, we add to each CD entitled t a link to the URL /showcd.php?title=t
<xsl:template match="cd">
<b><xsl:value-of select="artist"/></b>:
<a href="/showcd.php?title={./title}">
<xsl:value-of select="title"/>
</a>
</xsl:template>
view catalog5.xm
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71
UsingUsing <xsl:element> <xsl:element>
<xsl:template match="cd">
<b><xsl:value-of select="artist"/></b>:
<xsl:element name="a">
<xsl:attribute name="href">
showcd/?title=<xsl:value-of select="title"/>
</xsl:attribute>
<xsl:value-of select="title"/>
</xsl:element>
</xsl:template>
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On XSL CodeOn XSL Code
• Typically, an XSLT program can be written in several, very different ways- Templates can sometime replace loops and vice versa- Conditions can sometimes be replaced with XPath
predicates (e.g., in the select attribute) and vice versa
• A matter of convenience and elegancy
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On Recursive TemplatesOn Recursive Templates• It is not always possible to avoid recursive
templates- That is, use only the template of the root
• Suppose that we want to write an XSL stylesheet that generates a copy of the source document- It is rather easy to do it when the structure of the source
XML document is known
• Can we write an XSL stylesheet that does it for every possible XML document?- Yes! (see next slide)
74
<?xml version="1.0"?><xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0"> <xsl:output method="xml"/>
<xsl:template match="*"> <xsl:element name="{name()}"> <xsl:for-each select="@*"> <xsl:attribute name="{name()}"> <xsl:value-of select="."/> </xsl:attribute> </xsl:for-each> <xsl:apply-templates/> </xsl:element> </xsl:template>
</xsl:stylesheet>
Identity TransformationStylesheet
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Generating Valid XHTMLGenerating Valid XHTML
• By default, the documents that XSL stylesheets generate are not valid XHTML
• Next, we will show how XSL stylesheet can be changed in order to generate valid XHTML
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<?xml version="1.0" encoding="ISO-8859-1"?>
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match="/">
<html>
<head><title>cd catalog</title></head>
<body><h1>This is a cd catalog!</h1></body>
</html>
</xsl:template>
</xsl:stylesheet>
The Original XSL ExampleThe Original XSL Example
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<html>
<head>
<META http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>cd catalog</title>
</head>
<body>
<h1>This is a cd catalog!</h1>
</body>
</html>
Uppercase tag name, unclosed element
No DOCTYPE
The Original Transformation ResultThe Original Transformation Result
78
<?xml version="1.0" encoding="ISO-8859-1"?>
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns="http://www.w3.org/1999/xhtml">
<xsl:output
method="html"
doctype-public="-//W3C//DTD XHTML 1.0 Strict//EN"
doctype-system=
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"/>
<xsl:template match="/"> …
Modifying the XSL ExampleModifying the XSL Example
79
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>cd catalog</title>
</head>
<body>
<h1>This is a cd catalog!</h1>
</body>
</html>
META is not inserted
The Transformation ResultThe Transformation Result
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Some Other XSL ElementsSome Other XSL Elements
• The <xsl:text> element inserts free text in the output
• The <xsl:copy-of select="xpath"> creates a copy of the specified nodes
• The <xsl:comment> element creates a comment node in the result tree
• The <xsl:variable> element defines a variable (local or global) that can be used within the program
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Costello’s TutorialCostello’s Tutorial
Costello has an excellent, detailed tutorial- First part (xsl01.ppt) has many examples that do
not use recursion- Second part (xsl02.ppt) explains how to use
recursion and why it is needed (the identity
transformation shown earlier is from Costello’s
tutorial)
(See DBI timetable for a reference)
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W3Schools Tutorial on XSLTW3Schools Tutorial on XSLT
• The W3Schools XSLT Tutorial has (among other things) tables that list all the elements and functions of XSLT
• It also has some details about implementations- Some browsers may not implement all features or may
implement some features differently from the
specifications