Processing XML Processing XML using XSLT Processing XML documents with Java (DOM) Next week -- Processing XML documents with Java (SAX)

Processing XML using XSLT To use James Clark’s xt program visit his site at and click on XML. The following programs were tested with the command line C:>xt somefile.xml somefile.xsl resultfile.html The xt classes (and xslt processing) may also be accessed via a servlet.

The Catcher in the Rye J. D. Salinger Little, Brown and Company Input

<xsl:stylesheet xmlns:xsl=" version="1.0"> Processing

The Catcher in the Rye J. D. Salinger Little, Brown and Company Output

The Catcher in the Rye J. D. Salinger Little, Brown and Company Input

<xsl:stylesheet xmlns:xsl=" version="1.0"> The default rules matches the root, library and block elements.

The Catcher in the Rye J. D. Salinger Little, Brown and Company The output is the same.

The Catcher in the Rye J. D. Salinger Little, Brown and Company Cliff Notes on The Catcher in the Rye Two books in the input

<xsl:stylesheet xmlns:xsl=" version="1.0"> What’s the output?

The Catcher in the Rye J. D. Salinger Little, Brown and Company Cliff Notes on The Catcher in the Rye Illegal HTML

The Catcher in the Rye J. D. Salinger Little, Brown and Company Input

<xsl:stylesheet xmlns:xsl=" version="1.0"> <!-- --> We are not matching on publisher.

The Catcher in the Rye J. D. Salinger Little, Brown and Company We get the default rule matching the publisher and then printing its child.

The Catcher in the Rye J. D. Salinger Little, Brown and Company Input

<xsl:stylesheet xmlns:xsl=" version="1.0"> We can skip the publisher by matching and stopping the recursion.

The Catcher in the Rye J. D. Salinger

The Catcher in the Rye J. D. Salinger Little, Brown and Company The Catcher in the Rye J. D. Salinger Little, Brown and Company The Catcher in the Rye J. D. Salinger Little, Brown and Company A shelf has many books.

<xsl:stylesheet xmlns:xsl=" version="1.0"> Will this do the job?

The Catcher in the Rye J. D. Salinger Little, Brown and Company The Catcher in the Rye J. D. Salinger Little, Brown and Company The Catcher in the Rye J. D. Salinger Little, Brown and Company This is not what we want.

The Catcher in the Rye J. D. Salinger Little, Brown and Company The Catcher in the Rye J. D. Salinger Little, Brown and Company The Catcher in the Rye J. D. Salinger Little, Brown and Company Same input.

<xsl:stylesheet xmlns:xsl=" version="1.0"> Found a shelf Checks for a shelf and quits.

Found a shelf Output

The Catcher in the Rye J. D. Salinger Little, Brown and Company The Catcher in the Rye J. D. Salinger Little, Brown and Company The Catcher in the Rye J. D. Salinger Little, Brown and Company Same input.

<xsl:stylesheet xmlns:xsl=" version="1.0"> These are a few of my favorite books Produce a table of books.

These are a few of my favorite books 1 The Catcher in the Rye J. D. Salinger Little, Brown and Company 2 The XSLT Programmer's Reference Michael Kay Wrox Press 3 Computer Organization and Design Patterson and Henessey Morgan Kaufmann

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

XPATH First, we’ll look at three commonly used XSLT instructions: xsl:value-of xsl:template xsl:apply-templates

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

XPATH 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

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

XPATH 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.

The Tree Structure of an XML Document Alan Turing computer scientist mathematician cryptographer

Richard M Feynman physicist Playing the bongoes

/ person born = “1914” died = “1952” id=“p342” person name first_name Alan <!– Did the word “computer scientist” exist in Turing’s day?”-- > profession

The root Element Nodes Text Nodes Attribute Nodes Comment Nodes Processing Instructions Namespace Nodes Nodes seen by XPath Constructs not seen by XPath CDATA sections Entity references Document Type Declarations

Location Paths The root <xsl:stylesheet xmlns:xsl=" version="1.0" > matched the root matched the root

Location Paths Child element location paths (relative to context node) <xsl:stylesheet xmlns:xsl=" version="1.0" > computer scientist

Location Paths Attribute location paths (relative to context node) <xsl:stylesheet xmlns:xsl=" version="1.0" > 1912

Location Paths Attribute location paths (relative to context node) <xsl:stylesheet xmlns:xsl=" version="1.0" >

Location Paths Comment Location Step (comments don’t have names) <xsl:stylesheet xmlns:xsl=" version="1.0" > Did the word "computer scientist" exist in Turing's day?

Location Paths Comment Location Step <xsl:stylesheet xmlns:xsl=" version="1.0" > comment deleted Document content with comments replaced as shown. Default – no comments output

Location Paths Text Location Step (Text nodes don’t have names) <xsl:stylesheet xmlns:xsl=" version="1.0" > computer scientist

Location Paths Processing Instruction Location Step <xsl:stylesheet xmlns:xsl=" version="1.0" > type="text/xsl" href = "pi.xsl"

Location Paths Wild cards There are three wild cards: *, The * matches any element node. It will not match attributes, text nodes, comments or processing instructions nodes.

Location Paths Matching with * <xsl:stylesheet xmlns:xsl=" version="1.0" > Matches all elements and requests calls on sub-elements only. Nothing is displayed. The text nodes are never reached.

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

Location Paths Matching wild card matches all attribute nodes. XT does not like it in an but likes it in an

Location Paths Matching <xsl:stylesheet xmlns:xsl=" version="1.0" > p p4567

Location Paths Multiple matches with | Matches all the elements. Skips the text nodes unless they describe a profession or hobby.

Location Paths Selecting from all descendants with // // selects from all descendants of the context node as well as the context node itself. At the beginning of an Xpath expression, it selects from all descendants of the root node.

Location Paths Selecting from all descendants with // TuringFeynman

Location Paths Selecting from all descendants with // Alan

Location Paths Selecting from all descendants with // AlanRichard

Location Paths Selecting from all descendants with // Richard

Predicates In general, an Xpath expression may refer to more than one node. Predicates allow us to reduce the number of nodes we are interested in. Each step in a location path may have a predicate that selects from the node list that is current at that step in the expression. The boolean expression in the predicate is tested against each node in the context node list. If the expression is false then that node is deleted from the list.

Predicates Richard M Feynman

Predicates Richard M Feynman physicist Playing the bongoes

Predicates Alan Turing computer scientist mathematician cryptographer

Predicates Richard M Feynman physicist Playing the bongoes

Predicates <xsl:apply-templates select = < 1950]/ name[first_name='Alan']" /> Alan Turing

General XPath Expressions Xpath expressions that are not node sets can’t be used in the match attribute of an xsl:template element. They can be used for the values for the select attribute of xsl:value-of elements and in location path predicates.

General XPath Expressions

General XPath Expressions Xpath Functions Person Person 1 Person 2

General XPath Expressions Xpath Functions Mr. T. Mr. T. Alan Turing Node set converted to string

Escaping to Java Extension functions provide a mechanism for extending the capabilities of XSLT by escaping into another language Such as Java or JavaScript. If there is no namespace prefix on the function then it must be a core function built into XSLT. Otherwise, it’s an extension function.

General XPath Expressions Extended Xpath Functions <xsl:template name = "show-date" xmlns:Date = "

Escaping to Java Mon Mar 19 10:46:17 EST 2001

Escaping to Java // A simple bean saved under Www/beans/MyDate.java // The classpath c:\Jigsaw\Jigsaw\Jigsaw\Www\beans import java.util.*; public class MyDate { Date d; public MyDate() { d = new Date(); } public Date getDate() { return d; }

public String toString() { return "The date is " + d.toString(); } public static void main(String a[]) { MyDate x = new MyDate(); System.out.println(x); }

Escaping to Java <xsl:template name = "show-date" xmlns:Date = " The date is Mon Mar 19 11:17:24 EST 2001