Java and XML - Beginning Java - page 1268

<position x="10" y="10"/>
<bounds x="10" y="10"
width="42" height="42"/>

</circle>
<line angle="0.0">
<color R="0" G="0" B="255"/>
<position x="10" y="10"/>
<bounds x="10" y="10"
width="22" height="32"/>
<endpoint x="30" y="40"/>
</line>
<rectangle width="30.0" height="20.0" angle="0.0">
<color R="255" G="0" B="0"/>
<position x="30" y="40"/>
<bounds x="30" y="40"

width="32" height="22"/>

</rectangle>
</sketch>

Directory "TryParsingSchemaInstance"

This defines a sketch that consists of three elements: a circle, a line, and a rectangle. The location of the
schema is specified by the value for the noNamespaceSchemaLocation attribute, which here corresponds to
the Sketcher.xsd file in the Beg Java Stuff directory. You can save the document as sketch1.xml in the
same directory.
An XML document may have the applicable schema identified by the value for the noNamespaceSchem-
aLocation attribute, or the schema may not be identified explicitly in the document. You have the means
for dealing with both of these situations in Java.
A javax.xml.validation.Schema object encapsulates a schema. You create a Schema object by calling
methods for a javax.xml.validation.SchemaFactory object that you generate by calling the static
newInstance() method for the SchemaFactory class. It works like this:
SchemaFactory sf =
SchemaFactory.newInstance("http://www.w3.org/2001/XMLSchema");

A SchemaFactory object compiles a schema from an external source in a given Schema Definition Lan-
guage into a Schema object that can subsequently be used by a parser. The argument to the static newIn-
stance() method in the SchemaFactory class identifies the schema language that the schema factory can
process. The only alternative to the argument used in the example to specify the XML Schema language
is “ http://relaxng.org/ns/structure/1.0 ,” which is another schema language for XML. At the time of writing,
Schema objects encapsulating DTDs are not supported.
The javax.xml.XMLConstants class defines String constants for basic values required when you are
processing XML. The class defines a constant with the name W3C_XML_NS_URI that corresponds to the URI
for the Schema Definition Language, so you could use this as the argument to the newInstance() method
in the SchemaFactory class, like this:
SchemaFactory sf = SchemaFactory.newInstance(W3C_XML_NS_URI);

This statement assumes you have statically imported the names from the XMLConstants class.