book

Learning XSLT

by Michael Fitzgerald

November 2003

Beginner

368 pages

9h 33m

English

O'Reilly Media, Inc.

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Who Should Read This Book?About the ExamplesXSLT and XPath ReferenceHow This Book Is OrganizedConventions Used in This BookUsing ExamplesComments and QuestionsAcknowledgments
1.1. How XSLT Works1.1.1. A Ridiculous XML Document1.1.2. A First XSLT Stylesheet1.1.2.1. The stylesheet element1.1.2.2. The XSLT namespace1.1.2.3. The output element1.1.2.4. The template element1.1.2.4.1. The root node1.2. Using Client-Side XSLT in a Browser1.2.1. The XML Stylesheet Processing Instruction1.2.1.1. Attributes and pseudoattributes1.3. Using apply-templates1.3.1. Analysis of message.xml1.3.1.1. The XML declaration1.3.2. Running Xalan1.3.3. More About Xalan C++1.3.4. Using Other XSLT Processors1.3.5. Using xRay21.4. Summary
2.1. Outputting Text2.1.1. Using the text Element2.1.1.1. The disable-output-escaping attribute2.2. Literal Result Elements2.2.1. Adding a Namespace Prefix2.2.2. Literal Result Elements for HTML2.2.2.1. The META tag2.2.3. XHTML Literal Result Elements2.2.3.1. Attribute value templates2.2.3.2. Applying namespaces2.3. Using the Element Called element2.3.1. The namespace attribute2.4. Adding Attributes2.4.1. Reusing a Set of Attributes2.4.1.1. Chaining attribute sets2.5. Outputting Comments2.6. Outputting Processing Instructions2.6.1. Mixed Content2.6.2. Using Multiple Template Rules2.6.2.1. What can go in a template rule?2.6.3. Creating the PI and Putting It to Work2.7. One Final Example2.8. Summary
3.1. The Output Method3.1.1. The Default Output Methods3.1.1.1. Default HTML output3.1.1.2. Default XML output3.2. Outputting XML3.2.1. The XML Declaration3.2.1.1. Omitting the XML declaration3.2.1.2. The encoding declaration3.2.1.2.1. ISO/IEC 88593.2.1.2.2. UTF-8 and UTF-163.2.1.2.3. The Byte Order Mark3.2.2. Unicode and the Command Shell Window3.2.3. Using Character Map and UniPad3.2.3.1. Entities and text declarations3.2.3.2. The standalone declaration3.2.3.3. XML version information3.2.4. Controlling Document Type Declarations3.2.4.1. Validation with transformation3.2.4.2. Adding a document type declaration with a system identifier3.2.4.3. Adding a document type declaration with a public identifier3.2.4.4. Validating XHTML3.2.5. Outputting CDATA Sections3.3. Outputting HTML3.4. Outputting Text3.5. Using a QName Output Method3.6. Media Types3.7. Summary
4.1. The XPath Data Model4.1.1. XPath Nodes4.1.2. A View of the Tree4.1.3. What’s a Context?4.2. Location Paths4.3. Expressions4.4. What Is a Pattern?4.5. Predicates4.5.1. Matching Multiple Nodes with a Pattern4.6. Axes4.6.1. Unabbreviated Syntax4.6.2. Reaching Out of Context with Unabbreviated Syntax4.7. Name and Node Tests4.8. Doing the Math with Expressions4.9. Summary
5.1. Boolean Functions5.1.1. The lang( ) Function5.2. Node-Set Functions5.2.1. The id( ) Function5.3. Number Functions5.3.1. The sum( ) Function5.3.2. The round( ) Function5.4. String Functions5.4.1. The concat( ) Function5.4.2. The normalize-space( ), translate( ), and substring( ) Functions5.4.3. The generate-id( ) Function5.5. Summary
6.1. The copy Element6.1.1. Adding Attributes with copy6.1.2. The Identity Transform6.2. The copy-of Element6.3. Copying Nodes from Two Documents6.4. Summary
7.1. Defining Variables and Parameters7.1.1. Defining Default Values for Parameters7.1.2. Defining Values with Expressions and Templates7.1.2.1. Using the select attribute to define variables7.1.2.2. Using result tree fragments to define variables7.2. Using Variables7.3. Using Parameters7.3.1. Passing in a Parameter with Xalan7.3.2. Passing in a Parameter with Instant Saxon7.4. Invoking Templates with Parameters7.5. Using Result Tree Fragments7.6. Summary
8.1. Simple Ascending Sort8.2. Reversing the Sort8.3. By the Numbers8.4. Multiple Sorts8.5. The lang and case-order Attributes8.6. Summary

9.1. Numbered Lists9.1.1. The number Element9.1.2. The count Attribute9.1.3. More on Formatting9.2. Alphabetical Lists9.2.1. Using Uppercase9.2.2. Longer Alphabetical Lists9.3. Roman Numerals9.3.1. Uppercase Roman Numerals9.4. Inserting an Individual Formatted Value9.5. Numbering Levels9.5.1. Counting on Multiple Levels9.5.2. More Depth9.5.3. Counting on Any Level9.6. The from Attribute9.7. The lang and letter-value Attributes9.8. More Help with Formatted Numbers9.9. Summary
10.1. Template Priority10.1.1. The priority Attribute10.2. Calling a Named Template10.2.1. Using the name and match Attributes Together10.3. Using Templates with Parameters10.4. Modes10.5. Built-in Template Rules10.6. Summary
11.1. A Simple Key11.1.1. The key Element11.1.2. The key( ) Function11.2. More Than One Key11.3. Using a Parameter with Keys11.3.1. Passing in a Parameter to the Stylesheet11.4. Cross-Referencing with Keys11.5. Grouping with Keys11.6. Summary
12.1. The if Element12.2. The choose and when Elements12.2.1. The otherwise Element12.2.2. Processing More Than One Kind of Document12.3. Summary
13.1. Including Stylesheets13.2. Importing Stylesheets13.2.1. Import Tree13.2.2. Applying Imports13.3. Using the document( ) Function13.4. Summary
14.1. A Literal Result Element Stylesheet14.1.1. Pull and Push Stylesheets14.1.2. A Literal XHTML Stylesheet14.2. An Embedded Stylesheet14.3. Aliasing a Namespace14.4. Excluding Namespaces14.5. Summary
15.1. Xalan, Saxon, and EXSLT Extensions15.2. Using a Saxon Extension Attribute15.3. Result Tree Fragment to Node-Set15.4. Using EXSLT15.4.1. EXSLT’s exsl:node-set Function15.5. Fallback Behavior15.5.1. Invoking the Fallback Behavior15.6. Checking for Extension Availability15.7. Summary
16.1. New XSLT 2.0 Features16.2. New XPath 2.0 Features16.3. Multiple Result Trees16.4. Using Regular Expressions16.4.1. The matches( ) Function16.4.2. The replace( ) Function16.4.3. The analyze-string Element16.5. Grouping in XSLT 2.016.6. Extension Functions16.7. Summary
17.1. Running an XSLT Processor from Java17.1.1. The Moxie Source Code17.1.2. Looking at the Moxie Code17.1.3. Running Moxie17.1.4. Compiling Moxie17.1.5. Using Ant17.1.6. Other Java Resources17.2. Writing an XSLT Processor with C#17.2.1. The Pax Code17.2.2. Looking at the Pax Code17.2.3. Running Pax17.2.4. Compiling Pax17.3. Summary
18.1. The Ox Documentation Tool18.2. Signing Off
A.1. Installing and Running XSLT ProcessorsA.1.1. Installing and Running JavaA.1.1.1. Setting the path variableA.1.1.1.1. The path environment variable on WindowsA.1.1.1.2. The path environment variable on UnixA.1.1.2. Running the Java compilerA.1.2. Using the ClasspathA.1.2.1. The jar methodA.1.3. Installing and Running Instant SaxonA.1.3.1. Downloading Instant SaxonA.1.3.2. Running Instant SaxonA.1.4. Installing and Running Saxon (Full Java Version)A.1.4.1. Downloading SaxonA.1.4.2. Running SaxonA.1.4.3. Using a Windows batch file with SaxonA.1.4.4. Using a Unix shell script with SaxonA.1.5. Installing and Running MSXSLA.1.5.1. Downloading MSXSLA.1.5.2. Running MSXSLA.1.6. Installing and Running Xalan C++A.1.6.1. Downloading and installing Xalan C++A.1.6.2. Setting the path variable for Xalan on WindowsA.1.6.3. Setting the path variable for Xalan on a Unix platformA.1.6.4. Running Xalan C++A.2. Using jd.xsltA.2.1. Downloading and installing jd.xsltA.2.1.1. Running jd.xsltA.2.2. Using xmlspyA.2.3. Using xRay2

Content preview from Learning XSLT

Chapter 11. Using Keys

A key provides a means of identifying some of the data that is associated with it. A key might identify a record in a database, for example, or an element in a collection, as in Java. XSLT also uses keys.

XSLT’s support for keys is provided through the key element and the key( ) function in tandem. The key element declares the key, and the key( ) function invokes it. The examples that follow in this chapter will show you how to declare and apply keys in several ways, including grouping.

These examples are simple by design, but they don’t clearly demonstrate the main benefit of keys, which is better performance. One way you could see a performance hike would be to call a key repeatedly on a document with many nodes. The reason for improved performance is that an XSLT processor creates an internal index for nodes that makes finding those nodes much faster.

By the way, you can read about keys in Section 12.2 of the XSLT specification.

A Simple Key

Following is part of the valid XML document un.xml (found in examples/ch11), which stores information about the 190 member states of the United Nations (UN). Example 11-1 is just a fragment of the document as, at over 700 lines, it’s too long to list in its entirety.

Example 11-1. Information about countries that belong to the UN

<?xml version="1.0" encoding="ISO-8859-1"?> <un> <state cc="af"> <name>Afghanistan</name> <admitted>19 Nov. 1946</admitted> </state> <state cc="al"> <name>Albania</name> <admitted>14 Dec. 1955</admitted> ...