1 Dr Alexiei Dingli XML Technologies X-Languages

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Dr Alexiei Dingli

XML Technologies

X-Languages

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• X Link

• X Pointer

• X Path

• X Query (Brief)

• X Form (Brief)

• XSLT

• FO

Contents

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X Languages

X Query XPointer XLink

X Path

XSLT

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• Standard way of defining hyperlinks in XML

• Short for XML Linking

• Similar to HTML Links but more powerful

• Any element can have an XLink

X Link

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• In HTML we use the <A> tag

• In XML all tags can have a link

<homepages xmlns:xlink="http://www.w3.org/1999/xlink">

<homepage

xlink:type="simple" xlink:href="http://www.um.edu.mt">

University of Malta

</homepage>

</homepages>

X Link Syntax

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• Declare the namespace in the top element<homepages xmlns:xlink="http://www.w3.org/1999/xlink">

• Define a simple element i.e. Go from the current position to that address. Multidirectional are not supported by most browsers.

xlink:type="simple" xlink:href="http://www.um.edu.mt"

• To define whether to use the current window or a new one ...

xlink:show="new"

X Link Explanation

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• XLink gets more interesting when we want to access remote locations as resources, instead of standalone pages

• The value of the xlink:show attribute could have been set to "embed". This means that the resource should be processed inline within the page

• With XLink, you can also specify WHEN the resource should appear– xlink:actuate="onLoad" specifies that the resource should be loaded and

shown when the document loads

– xlink:actuate="onRequest" means that the resource is not read or shown before the link is clicked. This is very handy for low-bandwidth settings

Advanced X Links

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• XML Pointer Language

• Allow hyperlinks to point to specific parts of an XML document

• Uses XPath for navigation

X Pointer

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• If a hyperlink points to an XML document we can add an XPointer after the URL

href="http://www.example.com/cdlist.xml#id('rock').child(5)"

• Find the element with unique Id rock

• Point to the 5th item in the list

X Pointer Example

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href="http://www.example.com/cdlist.xml#id('rock')

Is equivalent to

href="http://www.example.com/cdlist.xml#rock

X Pointer Short Hand

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• Lies at the heart of the XML technologies

• Is a syntax for defining parts of document

• Uses path expressions to navigate

• Contains a library of standard function (over 100)

• Major element of XSLT

X Path

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• Element

• Attribute

• Text

• Namespace

• Processing-instruction (<?xml version="1.0"?>)

• Comment

• Root node

X Path Nodes

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• Parent

• Children

• Siblings

• Ancestors

• Descendants

Node relationships

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<?xml version="1.0" encoding="ISO-8859-1"?>

<bookstore>

<book>

<title lang="eng">Harry Potter</title>

<price>29.99</price>

</book>

<book>

<title lang="eng">Learning XML</title>

<price>39.95</price>

</book>

</bookstore>

Example

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Expression Description

nodename Selects all child nodes of the named node

/ Selects from the root node

// Selects nodes in the document from the current node that match the selection no matter where they are

. Selects the current node

.. Selects the parent of the current node

@ Selects attributes

Usage

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Path Expression Result

bookstore Selects all the child nodes of the bookstore element

/bookstore Selects the root element bookstoreNote: If the path starts with a slash ( / ) it always represents an absolute path to an element!

bookstore/book Selects all book elements that are children of bookstore

//book Selects all book elements no matter where they are in the document

bookstore//book Selects all book elements that are descendant of the bookstore element, no matter where they are under the bookstore element

//@lang Selects all attributes that are named lang

Examples

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/bookstore/book[1] Selects the first book element that is the child of the bookstore element.Note: IE5 and later has implemented that [0] should be the first node, but according to the W3C standard it should have been [1]!!

/bookstore/book[last()] Selects the last book element that is the child of the bookstore element

/bookstore/book[last()-1] Selects the last but one book element that is the child of the bookstore element

/bookstore/book[position()<3] Selects the first two book elements that are children of the bookstore element

//title[@lang] Selects all the title elements that have an attribute named lang

//title[@lang='eng'] Selects all the title elements that have an attribute named lang with a value of 'eng'

/bookstore/book[price>35.00] Selects all the book elements of the bookstore element that have a price element with a value greater than 35.00

/bookstore/book[price>35.00]/title Selects all the title elements of the book elements of the bookstore element that have a price element with a value greater than 35.00

Example predicates

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Wildcard Description

* Matches any element node

@* Matches any attribute node

node() Matches any node of any kind

Using Wildcards


/bookstore/* Selects all the child nodes of the bookstore element

//* Selects all elements in the document

//title[@*] Selects all title elements which have any attribute

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//book/title | //book/price Selects all the title AND price elements of all book elements

//title | //price Selects all the title AND price elements in the document

/bookstore/book/title | //price Selects all the title elements of the book element of the bookstore element AND all the price elements in the document

Selecting several paths

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AxisName Result

ancestor Selects all ancestors (parent, grandparent, etc.) of the current node

ancestor-or-self Selects all ancestors (parent, grandparent, etc.) of the current node and the current node itself

attribute Selects all attributes of the current node

child Selects all children of the current node

descendant Selects all descendants (children, grandchildren, etc.) of the current node

descendant-or-self Selects all descendants (children, grandchildren, etc.) of the current node and the current node itself

following Selects everything in the document after the closing tag of the current node

following-sibling Selects all siblings after the current node

namespace Selects all namespace nodes of the current node

parent Selects the parent of the current node

preceding Selects everything in the document that is before the start tag of the current node

preceding-sibling Selects all siblings before the current node

self Selects the current node

Axes

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• an axis (defines the tree-relationship between the selected nodes and the current node)

• a node-test (identifies a node within an axis)

• zero or more predicates (to further refine the selected node-set)

axisname::nodetest[predicate]

Location step

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Example Result

child::book Selects all book nodes that are children of the current node

attribute::lang Selects the lang attribute of the current node

child::* Selects all children of the current node

attribute::* Selects all attributes of the current node

child::text() Selects all text child nodes of the current node

child::node() Selects all child nodes of the current node

descendant::book Selects all book descendants of the current node

ancestor::book Selects all book ancestors of the current node

ancestor-or-self::book Selects all book ancestors of the current node - and the current as well if it is a book node

child::*/child::price Selects all price grandchildren of the current node

Location step example

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An absolute location path:

/step/step/...

A relative location path:

step/step/...

The difference is the initial /

Absolute vrs Relative

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Operator Description Example Return value

| Computes two node-sets //book | //cd Returns a node-set with all book and cd elements

+ Addition 6 + 4 10

- Subtraction 6 - 4 2

* Multiplication 6 * 4 24

div Division 8 div 4 2

= Equal price=9.80 true if price is 9.80false if price is 9.90

!= Not equal price!=9.80 true if price is 9.90false if price is 9.80

< Less than price<9.80 true if price is 9.00false if price is 9.80

<= Less than or equal to price<=9.80 true if price is 9.00false if price is 9.90

> Greater than price>9.80 true if price is 9.90false if price is 9.80

>= Greater than or equal to price>=9.80 true if price is 9.90false if price is 9.70

or or price=9.80 or price=9.70 true if price is 9.80false if price is 9.50

and and price>9.00 and price<9.90 true if price is 9.80false if price is 8.50

mod Modulus (division remainder) 5 mod 2 1

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xmlDoc=new ActiveXObject("Microsoft.XMLDOM");

xmlDoc.async=false;

xmlDoc.load("books.xml");

xpath="/bookstore/book[1]/title";

xmlDoc.selectNodes(xpath);

Programming example

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• Designed to query XML Data

• Like SQL for databases

• Built on XPath

X Query

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doc("books.xml")/bookstore/book/title

Load the document and use XPath to get the data

For more powerful queries use FLWOR expressions

XQuery Example

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• Similar to HTML forms but defined in XML

• Richer and more flexible

• Platform and device independent

• Standard in XHTML 2.0

X Forms

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X Forms Example

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• The form

• The XML

• The Text

X Forms Result

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• XML Stylesheet Language

• Consist of three parts– XSLT– Xpath– XSL-FO

XSL

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• XSL Transformations

• Transforms XML to another XML document

• Uses XPath to navigate

• Most important part of XSL

• Supported by most browsers

XSLT

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• Add

• Remove

• Sort

• Rearrange

• Perform Tests

• Make decisions

• Hide

• Etc ...

Power

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• Use XPath to define elements of source

• When a match occurs– Transform the matching part into the resulting

document

Workings

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CD Catalogue (XML)

CD Catalogue (XSL)

CD Catalogue (XML + XSL)

Combined by adding the following line in the XML document<?xml-stylesheet type="text/xsl" href="cdcatalog.xsl"?>

Example

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

Declaration part of a Stylesheet

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• XSL style sheet made up of different rules called templates

• The Match attribute is used to associate a template to an element in the XML document

<xsl:template>

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Simple Template 1

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Simple Template 1 Result

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Simple Template 2

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Simple Template 3

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Simple Template 4

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Simple Template 5

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Simple Template 6

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Simple Template 7

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Simple Template 8

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• Script to transform using Java Script and XSLT

From the Client Side

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<%

'Load XML

set xml = Server.CreateObject("Microsoft.XMLDOM")

xml.async = false xml.load(Server.MapPath("cdcatalog.xml"))

'Load XSL

set xsl = Server.CreateObject("Microsoft.XMLDOM")

xsl.async = false xsl.load(Server.MapPath("cdcatalog.xsl"))

'Transform file

Response.Write(xml.transformNode(xsl))

%>

From the Server Side (ASP)

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• Language for formatting XML objects

• Can output to screen, paper and other media

• XML files with output information (layout and content)

• Normally stored in .fo, .fob or even .xml

Formatting Objects

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Example FO

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< Root

^ Namespace

< One or more page template

< Page

content

Explanation

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• Pages (Contain many regions)

• Regions (Contain Block Areas)

• Block Areas (Contain Line Areas)

• Line Areas (Contain Inline Areas)

• Inline Areas

Areas

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• region-body (the body of the page)

• region-before (the header of the page)

• region-after (the footer of the page)

• region-start (the left sidebar)

• region-end (the right sidebar)

Regions

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Page Regions

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Page Example

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• Blocks flow into pages

Flow

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• xsl-region-body (into the region-body)

• xsl-region-before (into the region-before)

• xsl-region-after (into the region-after)

• xsl-region-start (into the region-start)

• xsl-region-end (into the region-end)

Where to flow?

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Block Area

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<fo:page-sequence>

<fo:flow flow-name="xsl-region-body"> <fo:block>



</fo:block>

</fo:flow>

</fo:page-sequence>

Block Example

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Block Attributes (1)• Block Margin

– margin

– margin-top

– margin-bottom

– margin-left

– margin-right

• Border style attributes

– border-style

– border-before-style

– border-after-style

– border-start-style

– border-end-style

– border-top-style (same as border-before)

– border-bottom-style (same as border-after)

– border-left-style (same as border-start)

– border-right-style (same as border-end)

• Border color attributes– border-color– border-before-color– border-after-color– border-start-color– border-end-color– border-top-color (same as border-before)– border-bottom-color (same as border-after)– border-left-color (same as border-start)– border-right-color (same as border-end)

• Border width attributes– border-width– border-before-width– border-after-width– border-start-width– border-end-width– border-top-width (same as border-before)– border-bottom-width (same as border-after)– border-left-width (same as border-start)– border-right-width (same as border-end)

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Block Attributes (2)• Block Padding

– padding– padding-before– padding-after– padding-start– padding-end– padding-top (same as padding-before)– padding-bottom (same as padding-after)– padding-left (same as padding-start)– padding-right (same as padding-end)

• Block Background– background-color– background-image– background-repeat – background-attachment (scroll or fixed)

• Font attributes– font-family– font-weight– font-style– font-size– font-variant

• Text attributes– text-align– text-align-last– text-indent– start-indent– end-indent – wrap-option (defines word wrap)– break-before (defines page breaks)– break-after (defines page breaks)– reference-orientation (defines text rotation

in 90" increments)

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Attribute Example

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Attribute Result

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Lists

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Tables

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XSLT + FOC

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• To use a .fo to generate a document in any other format use:

– Apache FO processor

Software Hint

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Questions?

Documents

1 Dr Alexiei Dingli XML Technologies X-Languages