XSLT

Preview:

DESCRIPTION

XSLT. Processing XML using XSLT Using XPath Escaping to Java. Processing XML using XSLT. Instructions for dowloading Xalan can be found in Lab 2. The following programs were tested with the command line C:>xalan somefile.xml somefile.xsl resultfile.html - PowerPoint PPT Presentation

Citation preview

Internet Technologies

XSLT

• Processing XML using XSLT

• Using XPath

• Escaping to Java

Internet Technologies

Processing XML using XSLT

Instructions for dowloading Xalan can be found in Lab 2.

The following programs were tested with the command lineC:>xalan somefile.xml somefile.xsl resultfile.html

The Xalan classes (and xslt processing) may also be accessed viaa servlet or Java application (see Lab 2).

Internet Technologies

<?xml version="1.0" ?><?xml-stylesheet type="text/xsl" href="demo1.xsl"?><book> <title>The Catcher in the Rye</title> <author>J. D. Salinger</author> <publisher>Little, Brown and Company</publisher> </book>

Input

Internet Technologies

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

<xsl:template match = "book"> <HTML><BODY><xsl:apply-templates/></BODY></HTML> </xsl:template> <xsl:template match = "title"> <H1><xsl:apply-templates/></H1> </xsl:template> <xsl:template match = "author"> <H3><xsl:apply-templates/></H3> </xsl:template> <xsl:template match = "publisher"> <P><I><xsl:apply-templates/></I></P> </xsl:template></xsl:stylesheet> Processing

Internet Technologies

<HTML><BODY> <H1>The Catcher in the Rye</H1> <H3>J. D. Salinger</H3> <P><I>Little, Brown and Company</I></P> </BODY></HTML>

Output

Internet Technologies

<?xml version="1.0" ?><?xml-stylesheet type="text/xsl" href="demo1.xsl"?><library><block><book> <title>The Catcher in the Rye</title> <author>J. D. Salinger</author> <publisher>Little, Brown and Company</publisher> </book></block></library>

Input

Internet Technologies

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"

version="1.0">

<xsl:template match = "book">

<HTML><BODY><xsl:apply-templates/></BODY></HTML>

</xsl:template>

<xsl:template match = "title">

<H1><xsl:apply-templates/></H1>

</xsl:template>

<xsl:template match = "author">

<H3><xsl:apply-templates/></H3>

</xsl:template>

<xsl:template match = "publisher">

<P><I><xsl:apply-templates/></I></P>

</xsl:template>

</xsl:stylesheet>

The default rules matchesthe root, library and block elements.

Internet Technologies

<HTML><BODY> <H1>The Catcher in the Rye</H1> <H3>J. D. Salinger</H3> <P><I>Little, Brown and Company</I></P> </BODY></HTML>

The output is the same.

Internet Technologies

<?xml version="1.0" ?><?xml-stylesheet type="text/xsl" href="demo1.xsl"?>

<book> <title>The Catcher in the Rye</title> <author>J. D. Salinger</author> <publisher>Little, Brown and Company</publisher> <book>Cliff Notes on The Catcher in the Rye</book> </book>

Two books in the input

Internet Technologies

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

<xsl:template match = "book"> <HTML><BODY><xsl:apply-templates/></BODY></HTML> </xsl:template>

<xsl:template match = "title"> <H1><xsl:apply-templates/></H1> </xsl:template>

<xsl:template match = "author"> <H3><xsl:apply-templates/></H3> </xsl:template>

<xsl:template match = "publisher"> <P><I><xsl:apply-templates/></I></P> </xsl:template>

</xsl:stylesheet>

What’s the output?

Internet Technologies

<HTML><BODY> <H1>The Catcher in the Rye</H1> <H3>J. D. Salinger</H3> <P><I>Little, Brown and Company</I></P> <HTML><BODY>Cliff Notes on The Catcher in the Rye</BODY></HTML> </BODY></HTML>

Illegal HTML

Internet Technologies

<?xml version="1.0" ?><?xml-stylesheet type="text/xsl" href="demo1.xsl"?>

<book> <title>The Catcher in the Rye</title> <author>J. D. Salinger</author> <publisher>Little, Brown and Company</publisher> </book>

Input

Internet Technologies

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

<xsl:template match = "book"> <HTML><BODY><xsl:apply-templates/></BODY></HTML> </xsl:template>

<xsl:template match = "title"> <H1><xsl:apply-templates/></H1> </xsl:template>

<xsl:template match = "author"> <H3><xsl:apply-templates/></H3> </xsl:template><!-- <xsl:template match = "publisher"> <P><I><xsl:apply-templates/></I></P> </xsl:template>--></xsl:stylesheet>

We are not matchingon publisher.

Internet Technologies

<HTML><BODY> <H1>The Catcher in the Rye</H1> <H3>J. D. Salinger</H3> Little, Brown and Company </BODY></HTML>

We get the default rule matching thepublisher and then printing its child.

Internet Technologies

<?xml version="1.0" ?><?xml-stylesheet type="text/xsl" href="demo1.xsl"?>

<book> <title>The Catcher in the Rye</title> <author>J. D. Salinger</author> <publisher>Little, Brown and Company</publisher> </book>

Input

Internet Technologies

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

<xsl:template match = "book"> <HTML><BODY><xsl:apply-templates/></BODY></HTML> </xsl:template>

<xsl:template match = "title"> <H1><xsl:apply-templates/></H1> </xsl:template>

<xsl:template match = "author"> <H3><xsl:apply-templates/></H3> </xsl:template>

<xsl:template match = "publisher"> <!-- Skip the publisher --> </xsl:template>

</xsl:stylesheet>

We can skip the publisherby matching and stoppingthe recursion.

Internet Technologies

<HTML><BODY> <H1>The Catcher in the Rye</H1> <H3>J. D. Salinger</H3> </BODY></HTML>

Internet Technologies

<?xml version="1.0" ?><?xml-stylesheet type="text/xsl" href="demo1.xsl"?><shelf> <book> <title>The Catcher in the Rye</title> <author>J. D. Salinger</author> <publisher>Little, Brown and Company</publisher> </book> <book> <title>The Catcher in the Rye</title> <author>J. D. Salinger</author> <publisher>Little, Brown and Company</publisher> </book> <book> <title>The Catcher in the Rye</title> <author>J. D. Salinger</author> <publisher>Little, Brown and Company</publisher> </book></shelf>

A shelfhas many books.

Internet Technologies

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

<xsl:template match = "book"> <HTML><BODY><xsl:apply-templates/></BODY></HTML> </xsl:template>

<xsl:template match = "title"> <H1><xsl:apply-templates/></H1> </xsl:template>

<xsl:template match = "author"> <H3><xsl:apply-templates/></H3> </xsl:template>

<xsl:template match = "publisher"> <i><xsl:apply-templates/></i> </xsl:template>

</xsl:stylesheet>

Will this do the job?

Internet Technologies

<HTML> <BODY> <H1>The Catcher in the Rye</H1> <H3>J. D. Salinger</H3> <i>Little, Brown and Company</i> </BODY></HTML><HTML> <BODY> <H1>The Catcher in the Rye</H1> <H3>J. D. Salinger</H3> <i>Little, Brown and Company</i> </BODY></HTML><HTML> <BODY> <H1>The Catcher in the Rye</H1> <H3>J. D. Salinger</H3> <i>Little, Brown and Company</i> </BODY></HTML>

This is not whatwe want.

Internet Technologies

<?xml version="1.0" ?><?xml-stylesheet type="text/xsl" href="demo1.xsl"?><shelf> <book> <title>The Catcher in the Rye</title> <author>J. D. Salinger</author> <publisher>Little, Brown and Company</publisher> </book> <book> <title>The Catcher in the Rye</title> <author>J. D. Salinger</author> <publisher>Little, Brown and Company</publisher> </book> <book> <title>The Catcher in the Rye</title> <author>J. D. Salinger</author> <publisher>Little, Brown and Company</publisher> </book></shelf>

Same input.

Internet Technologies

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

<xsl:template match = "shelf"> <HTML><BODY>Found a shelf</BODY></HTML> </xsl:template>

</xsl:stylesheet>

Checks for a shelf and quits.

Internet Technologies

<HTML><BODY>Found a shelf</BODY></HTML>

Output

Internet Technologies

<?xml version="1.0" ?><?xml-stylesheet type="text/xsl" href="demo1.xsl"?><shelf> <book> <title>The Catcher in the Rye</title> <author>J. D. Salinger</author> <publisher>Little, Brown and Company</publisher> </book> <book> <title>The Catcher in the Rye</title> <author>J. D. Salinger</author> <publisher>Little, Brown and Company</publisher> </book> <book> <title>The Catcher in the Rye</title> <author>J. D. Salinger</author> <publisher>Little, Brown and Company</publisher> </book></shelf>

Same input.

Internet Technologies

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

<xsl:template match = "shelf"> <HTML> <BODY> <b>These are a few of my favorite books</b> <table width = "640“ border = “5”> <xsl:apply-templates/> </table> </BODY> </HTML> </xsl:template> <xsl:template match = "book"> <tr> <td> <xsl:number/> </td> <xsl:apply-templates/> </tr> </xsl:template> <xsl:template match = "title | author | publisher"> <td><xsl:apply-templates/></td> </xsl:template></xsl:stylesheet>

Produce a table of books.

Internet Technologies

<HTML><BODY><b>These are a few of my favorite books</b><table width="640“ border = “5”> <tr><td>1</td> <td>The Catcher in the Rye</td> <td>J. D. Salinger</td> <td>Little, Brown and Company</td> </tr> <tr><td>2</td> <td>The XSLT Programmer's Reference</td> <td>Michael Kay</td> <td>Wrox Press</td> </tr> <tr>

<td>3</td> <td>Computer Organization and Design</td> <td>Patterson and Henessey</td> <td>Morgan Kaufmann</td> </tr></table></BODY></HTML>

Internet Technologies

Internet Technologies

XPATH

• Non-xml language used to identify particular parts of an xml document

• Used by XSLT for matching and selecting particular elements to be copied into the result tree.

• Used by Xpointer to identify a particular point in or part of an xml document that an Xlink links to.

Slides adapted from “XML in a Nutshell” by Harold

Internet Technologies

XPATH

First, we’ll look at three commonly used XSLT instructions:

xsl:value-of xsl:template xsl:apply-templates

Internet Technologies

XPATH

<xsl:value-of select = “XPathExpression” />

The xsl:value-of element computes the string value of an Xpathexpression and inserts it into the result tree. XPath allows us to select nodes in the tree and different node types produce differentvalues.

Internet Technologies

XPATH

<xsl:value-of select = “XPathExpression” />

element => the text content of the element after all tags are stripped text => the text of the node attribute => the value of the attribute root => the value of the root processing-instruction => the processing instruction data (<?, ?>, and the target are not included comment => the text of the comment (no comment symbols) namespace => the namespace URI node set => the value of the first node in the set

Internet Technologies

XPATH

<xsl:template match = “pattern” />

The xsl:template top-level element is the key to all of xslt.The match attribute contains a pattern (location path) againstwhich nodes are compared as they’re processed. If the patternmatches a node, then the contents are instantiated

Internet Technologies

XPATH

<xsl:apply-templates select = “XPath node set expression” />

Find and apply the highest priority template that matches the node set expression.

If the select attribute is not present then all children of the context node are processed.

Internet Technologies

The Tree Structure of an XML Document

<?xml version="1.0" ?><?xml-stylesheet type="text/xsl" href = "pi.xsl" ?><people> <person born="1912" died = "1954" id="p342"> <name> <first_name>Alan</first_name> <last_name>Turing</last_name> </name> <!-- Did the word "computer scientist" exist in Turing's day? --> <profession>computer scientist</profession> <profession>mathematician</profession> <profession>cryptographer</profession> </person>

See Harold Pg. 147

Internet Technologies

<person born="1918" died = "1988" id="p4567"> <name> <first_name>Richard</first_name> <middle_initial>&#x4D;</middle_initial> <last_name>Feynman</last_name> </name> <profession>physicist</profession> <hobby>Playing the bongoes</hobby> </person></people>

Unicode ‘M’

Internet Technologies

/

personborn = “1914”died = “1952”id=“p342”

person

name

first_name

Alan

<!– Did the word “computer scientist”exist in Turing’s day?”-- >

<?xml-stylesheet type="text/xsl" href = “some.xsl" ?>

profession

Internet Technologies

The rootElement NodesText NodesAttribute NodesComment NodesProcessing InstructionsNamespace Nodes

Nodes seen by XPath Constructs not seen by XPath

CDATA sectionsEntity referencesDocument Type Declarations

Internet Technologies

Note

The following appears in each example below so ithas been removed from the slides.

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"version="1.0"

>::</xsl:stylesheet>

Internet Technologies

Location Paths

• The root

<xsl:template match="/"><a>matched the root</a>

</xsl:template>

<?xml version="1.0" encoding="utf-8"?><a>matched the root</a>

Internet Technologies

Location Paths

• Child element location paths (relative to context node)

<xsl:template match="/"> <xsl:value-of select = "people/person/profession" /></xsl:template>

computer scientist

Internet Technologies

Location Paths

• Attribute location paths (relative to context node)

<xsl:template match="/"> <xsl:value-of select = "people/person/@born" /></xsl:template>

<?xml version="1.0" encoding="utf-8"?>1912

Internet Technologies

Location Paths

• Attribute location paths (relative to context node)<xsl:template match="/"> <xsl:apply-templates select = "people/person" /></xsl:template>

<xsl:template match = "person"> <date> <xsl:value-of select = "@born" /> </date></xsl:template>

<date>1912</date><date>1918</date>

Internet Technologies

Location Paths

• Comment Location Step (comments don’t have names)

<xsl:template match="/"> <xsl:value-of select = "people/person/comment()" /></xsl:template>

<?xml version="1.0" encoding="utf-8"?> Did the word "computer scientist" exist in Turing's day?

Internet Technologies

Location Paths

• Comment Location Step

<xsl:template match = "comment()" > <i>comment deleted</i></xsl:template>

Document content withcomments replaced as shown.Default – no comments output

Internet Technologies

Location Paths

• Text Location Step (Text nodes don’t have names)

<xsl:template match="/"> <xsl:value-of select = "people/person/profession/text()" /></xsl:template>

computer scientist

Internet Technologies

Location Paths

• Processing Instruction Location Step

<xsl:template match="/"> <xsl:value-of select = "processing-instruction()" /></xsl:template>

<?xml version="1.0" encoding="utf-8"?>type="text/xsl" href = "pi.xsl"

Internet Technologies

Location Paths

• Wild cards

There are three wild cards: *, node(), @*

The * matches any element node. It will not match attributes, text nodes, comments or processing instructions nodes.

Internet Technologies

Location Paths

• Matching with *<xsl:template match = "*" > <xsl:apply-templates select ="*" /></xsl:template>

Matches all elements and requestscalls on sub-elements only. Nothingis displayed. The text nodes are never reached.

Internet Technologies

Location Paths

• Matching with node()

The node() wild card matches all nodes: element nodes,text nodes, attribute nodes, processing instruction nodes,namespace nodes and comment nodes.

Not implemented in XT

Internet Technologies

Location Paths

• Matching with @*

The @* wild card matches all attribute nodes.

XT does not like it in an <xsl:template match ..>but likes it in an <xsl:apply-templates select=…>

Internet Technologies

Location Paths

• Matching with @*

<xsl:template match = "person" > <b> <xsl:apply-templates select = "@*" /> </b></xsl:template>

<?xml version="1.0" encoding="utf-8"?>

<b>19121954p342</b>

<b>19181988p4567</b>

Internet Technologies

Location Paths

• Multiple matches with |

<xsl:template match = "profession|hobby" > <activity> <xsl:value-of select = "text()"/> </activity></xsl:template>

<xsl:template match = "*" > <xsl:apply-templates /></xsl:template>

<xsl:template match = "text()" ></xsl:template>

Matches all the elements.Skips the text nodes unlessthey describe a professionor hobby.

Internet Technologies

Location Paths

• Selecting from all descendants with //

// selects from all descendants of the context node as well as the context nodeitself. At the beginning of an Xpathexpression, it selects from all descendantsof the root node.

Internet Technologies

Location Paths

• Selecting from all descendants with //

<xsl:template match = "//name/last_name/text()" > <xsl:value-of select = "." /></xsl:template>

<xsl:template match = "text()" ></xsl:template>

<?xml version="1.0" encoding="utf-8"?>TuringFeynman

Internet Technologies

Location Paths

• Selecting from all descendants with //

<xsl:template match = "/" >

<xsl:value-of select = "//first_name/text()" />

</xsl:template>

<?xml version="1.0" encoding="utf-8"?>Alan

Internet Technologies

Location Paths

• Selecting from all descendants with //

<xsl:template match = "/" >

<xsl:apply-templates select = "//first_name/text()" />

</xsl:template>

<xsl:template select = "text()" >

<xsl:value-of select = "." />

</xsl:template> <?xml version="1.0" encoding="utf-8"?>AlanRichard

Internet Technologies

Location Paths

• Selecting from all descendants with //

<xsl:template match = "/" >

<xsl:apply-templates select = "//middle_initial/../first_name" />

</xsl:template>

<xsl:template select = "text()" >

<xsl:value-of select = "." />

</xsl:template>

</xsl:stylesheet>

<?xml version="1.0" encoding="utf-8"?>Richard

Internet Technologies

PredicatesIn general, an Xpath expression may refer to morethan one node. Predicates allow us to reduce the number of nodes we are interested in.

Each step in a location path may have a predicatethat selects from the node list that is current at thatstep in the expression.

The boolean expression in the predicate is tested against each node in the context node list. If the expressionis false then that node is deleted from the list.

Internet Technologies

Predicates<xsl:template match = "/" >

<xsl:apply-templates select = "//profession[.='physicist']/../name" />

</xsl:template>

<xsl:template select = "text()" >

<xsl:value-of select = "." />

</xsl:template><?xml version="1.0" encoding="utf-8"?>

Richard M Feynman

Internet Technologies

Predicates<xsl:template match = "/" >

<xsl:apply-templates select = "//person[@id='p4567']" />

</xsl:template>

<xsl:template select = "text()" >

<xsl:value-of select = "." />

</xsl:template>

<?xml version="1.0" encoding="utf-8"?>

Richard M Feynman

physicist Playing the bongoes

Internet Technologies

Predicates<xsl:template match = "/" >

<xsl:apply-templates select = "//person[@born &lt;= 1915]" />

</xsl:template>

<xsl:template select = "text()" >

<xsl:value-of select = "." />

</xsl:template>

<?xml version="1.0" encoding="utf-8"?>

Alan Turing

computer scientist mathematician cryptographer

Internet Technologies

Predicates<xsl:template match = "/" >

<xsl:apply-templates select = "//person[@born &lt;= 1919 and @born &gt;= 1917]" />

</xsl:template>

<xsl:template select = "text()" >

<xsl:value-of select = "." />

</xsl:template>

<?xml version="1.0" encoding="utf-8"?>

Richard M Feynman

physicist Playing the bongoes

Internet Technologies

Predicates<xsl:template match = "/" >

<xsl:apply-templates select = "/people/person[@born &lt; 1950]/ name[first_name='Alan']" />

</xsl:template>

<?xml version="1.0" encoding="utf-8"?>

Alan Turing

Internet Technologies

General XPath Expressions

Xpath expressions that are not node sets can’t be usedin the match attribute of an xsl:template element.

They can be used for the values for the select attributeof xsl:value-of elements and in location path predicates.

Internet Technologies

General XPath Expressions<xsl:template match = "/" > <xsl:apply-templates select = "/people/person" /></xsl:template>

<xsl:template match = "person"> <xsl:value-of select="@born div 10" /></xsl:template>

<xsl:template match = "text()"></xsl:template>

<?xml version="1.0" encoding="utf-8"?>191.2191.8

Internet Technologies

General XPath ExpressionsXpath Functions

<xsl:template match = "/" > <xsl:apply-templates select = "/people/person" /></xsl:template>

<xsl:template match = "person"> Person <xsl:value-of select="position()" /></xsl:template>

<xsl:template match = "text()"></xsl:template> <?xml version="1.0" encoding="utf-8"?>

Person 1

Person 2

Internet Technologies

General XPath ExpressionsXpath Functions

<xsl:template match = "/" > <xsl:apply-templates select = "//name[starts-with(last_name,'T')]"/></xsl:template>

<xsl:template match = "name"> Mr. T. <xsl:value-of select="." /></xsl:template>

<?xml version="1.0" encoding="utf-8"?>

Mr. T. Alan Turing

Node set convertedto string

Internet Technologies

Escaping to Java

Extension functions provide a mechanism for extendingthe capabilities of XSLT by escaping into another languageSuch as Java or JavaScript.

If there is no namespace prefix on the function then it mustbe a core function built into XSLT.

Otherwise, it’s an extension function.

Internet Technologies

General XPath ExpressionsExtended Xpath Functions

<xsl:template match = "/" >

<xsl:call-template name = "show-date"/>

</xsl:template>

<xsl:template name = "show-date" xmlns:Date = "http://www.jclark.com/xt/java/java.util.Date"> <xsl:variable name = "today" select = "Date:new()" /> <xsl:value-of select = "Date:toString($today)" />

</xsl:template>

</xsl:stylesheet>Using James Clarke’sXT

Internet Technologies

Escaping to Java

<?xml version="1.0" encoding="utf-8"?>Mon Mar 19 10:46:17 EST 2001

Internet Technologies

Escaping to Java // A simple bean saved under Www/beans/MyDate.java// The classpath c:\Jigsaw\Jigsaw\Jigsaw\Www\beansimport java.util.*;

public class MyDate {

Date d;

public MyDate() {

d = new Date(); }

public Date getDate() { return d; }

Internet Technologies

public String toString() { return "The date is " + d.toString(); } public static void main(String a[]) {

MyDate x = new MyDate(); System.out.println(x); }}

Internet Technologies

Escaping to Java<xsl:template match = "/" > <xsl:call-template name = "show-date"/></xsl:template>

<xsl:template name = "show-date" xmlns:Date = "http://www.jclark.com/xt/java/MyDate"> <xsl:variable name = "today" select = "Date:new()" /> <xsl:value-of select = "Date:toString($today)" />

</xsl:template><?xml version="1.0" encoding="utf-8"?>The date is Mon Mar 19 11:17:24 EST 2001

Recommended