what is xml ?

What is What is XMLXML??

eeXXtensible tensible MMarkup arkup LLanguageanguage A subset of SGML (Standard A subset of SGML (Standard

Generalized Markup Language)Generalized Markup Language) Mechanism to identify structures in a Mechanism to identify structures in a

documentdocument Markup language for documents Markup language for documents

containing structured informationcontaining structured information Self-DescriptiveSelf-Descriptive Buzz WordBuzz Word

XML and HTMLXML and HTML Similar in natureSimilar in nature <tags> <tags>

LabelsLabels ElementsElements

<tags> plus <tags> plus contentcontent Reference SpecificationReference Specification

WWW consortium (W3C)WWW consortium (W3C) HTML transitionalHTML transitional XHTMLXHTML XML 1.0XML 1.0

XML Document XML Document StructureStructure

DeclarationDeclaration ElementsElements AttributesAttributes Character DataCharacter Data Processing InstructionsProcessing Instructions CommentsComments Entity ReferencesEntity References

DeclarationDeclaration

<xml version=“1.0” encoding=“iso-8859-<xml version=“1.0” encoding=“iso-8859-1”>1”>

Start of the fileStart of the file OptionalOptional Future proofFuture proof

ElementsElements

<Report><Report>XML ReportXML Report

</Report></Report> Highest level termed as the root Highest level termed as the root

elementelement Contains:Contains:

Start tagStart tag Some ContentSome Content End tagEnd tag

AttributesAttributes

<Report <Report Author=“Stevie”Author=“Stevie”>>

XML ReportXML Report

</Report></Report> Contains:Contains:

NameName ValueValue

Character DataCharacter Data

<Report Author=“Stevie”><Report Author=“Stevie”>

<type>XML </type> Report<type>XML </type> Report

</Report></Report> Element ContentElement Content Special SymbolsSpecial Symbols

‘‘&’ and ‘<‘&’ and ‘<‘ See Entity ReferencesSee Entity References

CommentsComments

<!-- This is a Comment --><!-- This is a Comment -->

Entity ReferencesEntity References

EntityEntity CharacterCharacter

&lt;&lt; <<

&gt;&gt; >>

&amp;&amp; &&

&apos;&apos; ‘‘

&quot;&quot; ““

Processing InstructionsProcessing Instructions

<?, <?, and end with the stringand end with the string ?> ?> Show a processing instruction at the Show a processing instruction at the

appropriate place in the node tree appropriate place in the node tree (DOM)(DOM)

Firing a processing instruction event Firing a processing instruction event (SAX)(SAX)

Well-Formed XMLWell-Formed XML

Tags must be nested properlyTags must be nested properly All start tags must have end tagsAll start tags must have end tags Use quotation marks properly for Use quotation marks properly for

tag attributestag attributes Use entity referencesUse entity references

Document Type Document Type DefinitionDefinition

Set of rulesSet of rules May be included in the document May be included in the document

itselfitself May be linked externallyMay be linked externally Confirming to a DTDConfirming to a DTD

Well-formedWell-formed validvalid

Document Type Document Type DefinitionDefinition

** <!DOCTYPE rootElementName [<!DOCTYPE rootElementName [

……insert declarations here…insert declarations here…

]>]>

** <!Element <!Element element element ((sub1sub1, , sub2sub2,,…,…,subnsubn)>)>

** <!ATTLIST <!ATTLIST element name (value1|element name (value1|value2)value2)

XML ParsingXML Parsing

Document Object Model (DOM)Document Object Model (DOM) Simple API for XML (SAX)Simple API for XML (SAX)

Document Object Model Document Object Model ((DOMDOM))

Document Model drivenDocument Model driven Build a tree model of the elements in Build a tree model of the elements in

the documentthe document Allow for application to access the Allow for application to access the

treetree DOM XML parserDOM XML parser

Converts XML documents into Java Tree Converts XML documents into Java Tree object modelobject model

Simple API for XML Simple API for XML ((SAXSAX))

Event drivenEvent driven SAX XML parser processes elements SAX XML parser processes elements

seriallyserially XML application provides callback XML application provides callback

functions to handle elementsfunctions to handle elements

Freely Available XML Freely Available XML ParsersParsers

Apache Software Foundation Xerces Apache Software Foundation Xerces XML Parser (XML Parser (xml.apache.orgxml.apache.org)) Open sourceOpen source

Oracle XML Parser Version 2 (Oracle XML Parser Version 2 (www.oracle.com/xmlwww.oracle.com/xml)) Must registerMust register

SAX2 Parser (SAX2 Parser (www.megginsion.com/SAXwww.megginsion.com/SAX)) Freely availableFreely available

ReferencesReferences

http://www.w3.org/XMLhttp://www.w3.org/XML http://www.xml.comhttp://www.xml.com http://www.w3schools.com/xml/http://www.w3schools.com/xml/

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