XSLT I Robin Burke ECT 360. Outline XSLT processing XSLT syntax XPath XSLT basics Lab.

XSLT I

Robin Burke

ECT 360

Outline

XSLT processing XSLT syntax XPath XSLT basics Lab

Admin

Announcement Milestone #4

high-techentrepreneurshipnetworking event

Friday, October 21 5-7pm, CTI Collaboration Lab, Free

Surf to www.depaulcti.com for more information

Have you ever thought of using your IT skills to start your own company?

Join other CTI students and alumni in exploring the possibilities. e, CTI’s new high-tech entrepreneurship club invites you to an open house to mingle, network, and learn. We will present info on DePaul’s New Venture (business plan) Competition, with $5,000 in prizes – and help you find teammates. Refreshments served.

XML

XSL "family" of standards

XSL-FO formatting objects typesetting document = a set of geometric areas organized on

pages XSLT

transformations XPath

supports both a language for addressing individual XML nodes

XSL-FO Example

XMLdocument

XML-FOdocument

PDFdocument

XSLTstylesheet

XSLTengine

Renderingengine

XSLT HTML example

XMLdocument

HTMLdocument

XSLTstylesheet

XSLTengine

Browser

XSLT syntax

XML document stylesheet

root element templates

"rule-based" processing

XSLT Processing

Let L be a list of nodes Let T be a list of templates style (L, T) =

Find a template t matching L• Instantiate t using L

• May call style (L', T)

• Return instantiated template To process a document

style ( { root }, T )

Special purpose

XSLT is not a general-purpose programming languagelacks many conventional facilitiestechnically a "tree-rewriting" language

XSLT 2.0is more general purpose

Example

<?xml version="1.0" encoding="UTF-8"?><xsl:stylesheet version="1.0"

xmlns:xsl="http://www.w3.org/1999/XSL/Transform"><xsl:output method="html" version="4.0" encoding="UTF-8" indent="yes"/><xsl:template match="/">

<html><head>

<title>Jeep suppliers</title></head><body>The first one is

<xsl:value-of select="/child::entries/child::entry[position() =

1]/child::address/child::name/child::text()" /></body></html>

</xsl:template></xsl:stylesheet>

Note

stylesheet element output type element

Running example

value-of1

XPath

XPath expression"/child::entries/child::entry[position() =

1]/child::address/child::name/child::text()"

How to read "/" = root and delimiter for steps axis::step = a move in the XML document

• :: = "that is" or "that are" [] = apply some predicate position () = compute the position of this

element in its list of siblings text() = the element content

Result is a set of nodes

Axes

self this node

child immediate descendant

descendant any descendant

attribute attribute list

following siblings to the right

preceding siblings to the left

Steps

Depends on axis element name attribute name can be associated with a predicate

foo[attribute::bar='5']entry[position() = 2]

XPath shortcuts

Axes can be abbreviated default = child @ = attribute // = descendant . = self .. = parent

Steps text() can be omitted [position() = n] can be [n]

Abbreviated version"/child::entries/child::entry[1]/child::address/child::name/child::text()""/entries/entry[1]/address/name"

Example

with simplified syntax

XML Document

entries

entry

address descrip

name line line phone

TEXTA & B

PerformanceAutomotive,

Inc.

TEXT20 FourthAvenue

TEXTHawthorne,NJ 07506

TEXT201-427-4464

TEXTEarly pickups and wagons;

has '45-87 Jeep parts

advertiser = "true"averageRating = "3.3" entry

address descrip

name line line phone

TEXTAJ's 4 WheelDrive Center

TEXT86 Guinter

Road

TEXTJersey Shore,

PA 17740

TEXT570-398-7520

TEXTFiberglass bodies and

accessories CJ-2A thruWrangler; one piece Wrangler

hood/fenders, tops

averageRating = "4.1"

web

TEXTwww.ajsjeepb

odies.com

Paths

All "name" elements? All advertisers? All non-advertisers? The rating of the second entry? All advertisers with a rating above 3? The second line of every address?

For-each

May want to operate on all nodes in a set

for-each elementinstantiates contents once for every

node in set

Example

listing just names

Multiple templates

Typically a stylesheet will have multiple templatesEasier to read / debugTemplates often correspond to

elementsMore modular

Templates

template element match attribute

• describes nodes that use the template content

• template to instantiate apply-templates element

select attribute• what nodes to use

position shows where in the parent element the result is inserted

Example

Whitespace

XSLT automatically removes whitespacethis is often correctwhen it isn't

• use text element

Path mismatch

Biggest source of errorsend path has no content

Check pathlocal pathtemplate matchapply-template select

Match/select should overlap by one step

Example

template choice

Building an element

<xsl:element name="a">

<xsl:attribute name="href">http://

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

</xsl:attribute>

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

</xsl:element>

Becomes

<a href="http://foo.org/">foo.org</a>

Alternate syntax

<a href="http://{.}">

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

Becomes

<a href="http://foo.org/">foo.org</a>

Sorting

We can sort node lists after they are selectedbefore they are operated onfor-eachapply-templates

Embed sort element

Sorting, cont'd

<xsl:apply-templates select="some/path">

<xsl:sort select="whatever/@foo" />

</xsl:apply-templates>

What does this do?

Example

complex selection and sorting

Break / Lab

XSLT I Robin Burke ECT 360. Outline XSLT processing XSLT syntax XPath XSLT basics Lab.

Documents

Transcript of XSLT I Robin Burke ECT 360. Outline XSLT processing XSLT syntax XPath XSLT basics Lab.