Java Reference
In-Depth Information
identifies the target namespace for the schema, and the second value (
recipe.xsd
)
identifies the location of the schema within this namespace.
Note
SchemafilesthatconformtoXMLSchema'sgrammararecommonlyassigned
the
.xsd
file extension.
If an XML document declares a namespace (
xmlns
default or
xmlns:
prefix
),
thatnamespacemustbemadeavailabletotheschemasothatavalidatingparsercanre-
solveallreferencestoelementsandotherschemacomponentsforthatnamespace.We
alsoneedtomentionwhichnamespacetheschemadescribes,andwedosobyincluding
the
targetNamespace
attributeonthe
schema
element.Forexample,supposeour
recipe document declares a default XML namespace, as follows:
<?xml version="1.0"?>
<recipe xmlns="http://www.tutortutor.ca/">
targetNameSpace
and the recipe document's default namespace as
tar-
getNameSpace
's value, as follows:
<xs:schema targetNamespace="http://www.tutortutor.ca/"
xmlns:xs="http://www.w3.org/2001/XMLSchema">
Perhaps you're wondering why you need to learn about XML Schema when DTD
shouldbegoodenoughforyourXMLprojects.ThereasonforlearningXMLSchemais
that
Chapter11
introducesyoutotheXML-basedWebServicesDescriptionLanguage
(WSDL), and the WSDL example that's presented in that chapter includes an XML
Schema-based schema.
Parsing XML Documents with SAX
Simple API for XML (SAX)
isanevent-basedAPIforparsinganXMLdocumentsequen-
tiallyfromstarttofinish.AsaSAX-orientedparserencountersanitemfromthedocu-
ment's
infoset
(anabstractdatamodeldescribinganXMLdocument'sinformation—see
http://en.wikipedia.org/wiki/XML_Information_Set
)
, it makes this
itemavailabletoanapplicationasan
event
,bycallingoneofthemethodsinoneofthe
application's
handlers
(anobjectwhosemethodsarecalledbytheparsertomakeevent
information available), which the application has previously registered with the pars-
er.Theapplicationcanthen
consume
thiseventbyprocessingtheinfosetiteminsome
manner.
