Sheet 1XML Technology in E-Commerce 2001Lecture 7 XML Technology in E-Commerce Lecture 7 XSL...

Sheet 1XML Technology in E-Commerce 2001 Lecture 7

XML Technology in E-Commerce

Lecture 7

XSL Formatting Objects, Java Data Binding


• XSL Formatting Objects– Formatting Objects as a part of XSL suite;

– Page Model;

– Creating Templates;

– Creating Blocks and Inline elements;

• Java Data Binding– Purpose of Data Binding: translation of XML

documents to application objects;

– Examples:• Castor;

• Jato;

Lecture Outline


XML

XML Namespaces

XPath

XPointerXSLT

XLink

XML Schema

XML Languages

Parser

DOMSAX

Software Application

Overview

XSL FO

Data Binding Facility


Rendering XML• Transformation to a document suitable for presentation

on a device like display, aural device, etc;

• The result tree has a formatting semantics expressed in terms of formatting objects;

XMLDocument

CSSStylesheet Browser

Transformation(XSLT)

FODocument

HTML

WML

PDF


Formatting Objects• After an XSLT transformation the result tree can

contain nodes that are formatting objects;• Formatting objects correspond to typographic

abstractions like page, paragraph, table;• Finer control on the presentation is provided

through the properties of the formatting objects;• XSL FO provides XML vocabulary to specify the

presentation in terms of formatting objects and properties;


DemoConverting FO Tree to PDF

• Demo - Deitel 13.3, fig. 13.2, page 356;• Tools:

– Java 2;

– Apache FOP tool (http://xml.apache.org/fop/);

• Demo files:– welcome.fo;

– welcome.pdf;


Region-before

Region-after

Reg

ion-

star

t

Reg

ion-

end

Region-body

Page Model

• Simplified page and its regions used in structures that contain formatting objects

Page


Setting Up Page Templates<fo:root xmlns:fo = "http://www.w3.org/1999/XSL/Format">

<fo:layout-master-set>

<fo:simple-page-master master-name = "layout1"

page-height = "4in">

…………………………………………………….</fo:root>

• layout-master-set: defines page templates that can be used for page generation;

• simple-page-master: used for the generation of pages. The pages come from the page-sequence element;


Setting Up Page Regions

<fo:simple-page-master master-name = "layout1"

page-height = "4in">

<fo:region-body margin-top = "1in"

margin-bottom = "1in" margin-left = "1.5in"

margin-right = "1.5in"/>

<fo:region-before extent = "1in" margin-top = "0.2in"

margin-bottom = "0.2in" margin-left = "0.2in"

margin-right = "0.2in"/>

</fo:simple-page-master>


Describing the Page Content

<fo:page-sequence master-name = "run">

<fo:static-content flow-name = "xsl-region-before">

<fo:block font-size = "10pt" line-height = "12pt"

font-family = "sans-serif">

page <fo:page-number/>

</fo:block>

</fo:static-content>

……………………………………….

static-content element causes page numbers to be included in each page header;


Creating Paragraphs and Inline elements

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

<fo:block font-size = "36pt"

font-family = "sans-serif" font-weight = "bold"

space-after.optimum = "24pt" color = "blue"

text-align = "center">Welcome!

</fo:block>

……………………………………………………..

<fo:block font-size = "12pt"

font-family = "sans-serif" line-height = "14pt"

space-after.optimum = "12pt">Deitel & Associates,

Inc. is a member of the

<fo:inline-sequence font-weight = "bold">World

Wide Web</fo:inline-sequence>

Consortium.

</fo:block>

block elements create paragraphs

inline element definesdifferent formattingfor a portion of text ina paragraph


DemoXSLT Transformation to FO Document

• Demo - Deitel 13.3, fig. 13.5, page 361;• Tools:

– Java 2;

– XML Spy with XSLT processor;

– Apache FOP tool (http://xml.apache.org/fop/);

• Demo files:– letter.xml;

– letter.xsl;


Summary on Formatting Objects

Read: Deitel 13

Assignment: Deitel Ex 13.3

• Part of XSL Suite;• XML application that provides vocabulary for

specifying formatting suitable for print media and aural devices ;

• Apache FOP tool allows easy generation of PDF files from XML documents;


• XSL Formatting Objects– Formatting Objects as a part of XSL suite;

– Page Model;

– Creating Templates;

– Creating Blocks and Inline elements;

• Java Data Binding– Purpose of Data Binding: translation of XML

documents to application objects;

– Examples:• Castor;

• Jato;

Lecture Outline


XML Processing

XML Parser

DOMSAX


XML Document

General Schema for XML Processing:

• Software application recognizes the markups in the XML doc;

• The application is bound to a low-level APIs (SAX, DOM);

• Dependence on the document format. Navigation through the document structure is rigidly encoded in the application;


Data Access• Example (simple address):<address>

<street>Baker Street 221b</street>

<city>London</city>

</address>

• Having the address element, obtaining the street through DOM is:

Node str=address.getFirstChild();

String street=str.getFirstChild().getNodeValue();

• But if we have the XML converted to an application

object address, the previous could be:

String street=address.getStreet();


The Idea behind the Data Binding

XML Parser

DOMSAX


XML Document

InterpreterMapping

Rules

Application Objects

• The application logic doesn’t contain code for XML data access;

• Conversion from XML to application objects is done by an Interpreter on the base of Mapping Rules. This process is called unmarshalling;

• The process of serialization of a set of objects to XML document is called marshalling;


Data Binding

Schema(DTD or XML Schema)

XML Document

Classes

Objects

Compile

Unmarshal

Marshal

Instance ofConforms to

Functionality of Data Binding Facility


Data Binding

• Every data binding implementation has to provide answer to two questions:– How to convert a schema to a hierarchy of

classes;

– What are the rules for mapping from and to XML and how they are represented;

• Two data binding implementations:– Castor (http://castor.exolab.org/);

– Jato (www.krumel.com/jato);


Castor

• Java-based data binding framework that supports marshalling and unmarshalling;

• Generates source of the classes on the base of XML Schema;

• Can use already existing application classes;

• Uses class and field descriptors to represent the mapping information;

• Based on Java Beans component model;


Class Descriptors• Mapping information is represented from

the Java object’s point of view;• Description is made on the base of Java

Beans name conventions;• Description takes the form of an XML

document;• Descriptors specify the mapping of classes

and fields to XML elements and attributes;• Example files for a simple order -

order.xml, MyOrder.java, Item.java, mapping.xml;


Jato

• Library for transforming XML to Java and Java to XML;

• JavaBeans naming convention support;• The correspondence between XML

elements and attributes and Java objects is specified in Jato transformation XML document;

• Transformation document is written in Jato script;


Jato Transformations

Jato Script XML Doc

Jato Interpreter

Object Helper

Jato Script XML Helper

XML Generator

XML

Objects

XML to Java Java to XML


XML to Java Example<system-properties>

<property name="awt.toolkit" value="sun.awt.windows.WToolkit" />

</system-properties>

We want to create an object instance of java.util.Properties class:<Jato:java-defs xmlns:Jato='http://www.krumel.com/jato' >

<Jato:import>java.util.*</Jato:import>

<Jato:translate elt='system-properties'>

<Jato:object class='Properties' publish='props’>

<Jato:on-elt name='property' action='Jato:invoke’ method='setProperty'>

<Jato:param type='string' path='@name'/>

<Jato:param type='string' path='@value'/>

</Jato:on-elt>

</Jato:object>

</Jato:translate>

</Jato:java-defs>


Summary on Data Binding

• Frameworks for translating XML to a set of application objects and objects to XML document;

• Usually uses Java language and JavaBeans naming conventions;

• Correspondence between XML and objects is specified in a separate descriptor document by using declarative syntax;

• Generation of classes on the base of DTD/XML Schema;

Sheet 1XML Technology in E-Commerce 2001Lecture 7 XML Technology in E-Commerce Lecture 7 XSL...

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