Using JAXB

1. Using JAXB Revisited

2. An XSDL Document for an ItemList <?xml version="1.0" encoding="utf-8"?> <xsd:schema xmlns:xsd='http://www.w3.org/2001/XMLSchema'> <xsd:element name="itemList"> <xsd:complexType> <xsd:sequence> <xsd:element ref="item" minOccurs="0" maxOccurs="3"/> </xsd:sequence> </xsd:complexType> </xsd:element>

3. <xsd:element name="item"> <xsd:complexType> <xsd:sequence> <xsd:element ref="name"/> <xsd:element ref="quantity"/> </xsd:sequence> </xsd:complexType> </xsd:element> <xsd:element name="name" type="xsd:string"/> <xsd:element name="quantity" type="xsd:short"/> </xsd:schema>

4. A Document Instance <?xml version="1.0" encoding="utf-8"?> <itemList xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance' xsi:noNamespaceSchemaLocation="itemList.xsd"> <item> <name>pen</name> <quantity>5</quantity> </item> <item> <name>eraser</name> <quantity>7</quantity> </item> <item> <name>stapler</name> <quantity>2</quantity> </item> </itemList>

5. An Ant Build file <?xml version="1.0"?> <!– adapted from Sun’s jaxb build file  <project basedir="." default="run"> <path id="classpath"> <fileset dir="D:\jwsdp-1.2\jaxb\lib" includes="*.jar"/> <fileset dir="D:\jwsdp-1.2\common\lib" includes="*.jar"/> <fileset dir="D:\jwsdp-1.2\jaxp\lib\endorsed" includes="*.jar"/> <fileset dir="D:\jwsdp-1.2\jwsdp-shared\lib" includes="*.jar"/> <fileset dir="D:\jwsdp-1.2\jaxp\lib" includes="*.jar"/> <pathelement location="."/> </path>

6. <taskdef name="xjc" classname="com.sun.tools.xjc.XJCTask"> <classpath refid="classpath" /> </taskdef> <!-- generate Java source files --> <target name="generate"> <!-- generate the Java content classes from the schema --> <echo message="Compiling the schema..."/> <xjc schema="itemList.xsd" target="." package="itemListAPI"/> <!-- generate the javadocs from the content classes --> <mkdir dir="docs/api"/> <javadoc packagenames="itemListAPI" sourcepath="." destdir="docs/api" windowtitle="Generated Interfaces for itemList.xsd"> <classpath refid="classpath" /> </javadoc>

7. <!-- compile all of the java sources --> <echo message="Compiling the java source files..."/> <javac srcdir="." destdir="." debug="on"> <classpath refid="classpath" /> </javac> </target> <target name="JustJava"> <!-- compile all of the java sources --> <echo message="Compiling the java source files..."/> <javac srcdir="." destdir="." debug="on"> <classpath refid="classpath" /> </javac> </target>

8. <target name="JustJavaRun"> <echo message="java runtime"/> <java classname="Main" fork="true"> <classpath refid="classpath" /> </java> </target> <target name="run" depends="generate"> <echo message="Running the sample application..."/> <java classname="Main" fork="true"> <classpath refid="classpath" /> </java> </target> </project>

9. Running the build D:\McCarthy\www\95-733\examples\struts1\src\VO>ant generate Buildfile: build.xml generate: [echo] Compiling the schema... [xjc] Compiling file:/D:/McCarthy/www/95-733/examples/struts1/src/VO/itemL ist.xsd [xjc] Writing output to D:\McCarthy\www\95-733\examples\struts1\src\VO [javadoc] Generating Javadoc [javadoc] Javadoc execution [javadoc] Loading source files for package itemListAPI... [javadoc] Constructing Javadoc information... [javadoc] Standard Doclet version 1.4.2 [javadoc] Building tree for all the packages and classes... [javadoc] Building index for all the packages and classes... [javadoc] Building index for all classes... [echo] Compiling the java source files... [javac] Compiling 42 source files to D:\McCarthy\www\95-733\examples\struts1 \src\VO BUILD SUCCESSFUL

10. Viewing the docs

11. Write the client import java.io.File; import java.io.IOException; import java.math.BigDecimal; import javax.xml.bind.JAXBContext; import javax.xml.bind.JAXBException; import javax.xml.bind.Marshaller; import javax.xml.bind.UnmarshalException; import javax.xml.bind.Unmarshaller; import javax.xml.bind.ValidationEvent; import javax.xml.bind.util.ValidationEventCollector; // import java content classes generated by binding compiler import itemListAPI.*; public class Main { // This sample application demonstrates how to enable validation during // the unmarshal operations.

12. public static void main( String[] args ) { try { // create a JAXBContext capable of handling classes generated into // the itemListAPI package JAXBContext jc = JAXBContext.newInstance( "itemListAPI" ); // create an Unmarshaller Unmarshaller u = jc.createUnmarshaller(); // enable validation u.setValidating( true );

13. // in this example, we will allow the Unmarshaller's default // ValidationEventHandler to receive notification of warnings // and errors which will be sent to System.out. The default // ValidationEventHandler will cause the unmarshal operation // to fail with an UnmarshalException after encountering the // first error or fatal error. // unmarshal an invalid itemList instance document into a tree of Java // content objects composed of classes from the itemListAPI package. ItemList itemList = (ItemList)u.unmarshal( new File( "itemList.xml" ) ); java.util.List list = itemList.getItem(); System.out.println("The length of the list is " + list.size());

14. int n = list.size(); for(int k = 0; k < n; k++) { ItemType it = (ItemType)list.get(k); String st = it.getName(); System.out.println(st); } } catch( UnmarshalException ue ) { // The JAXB specification does not mandate how the JAXB provider // must behave when attempting to unmarshal invalid XML data. In // those cases, the JAXB provider is allowed to terminate the // call to unmarshal with an UnmarshalException. System.out.println( "Caught UnmarshalException" ); } catch( JAXBException je ) { je.printStackTrace(); } } }

15. Running the Client D:\McCarthy\www\95-733\examples\struts1\src\VO>ant JustJavaRun Buildfile: build.xml JustJavaRun: [echo] java runtime [java] The length of the list is 3 [java] pen [java] eraser [java] stapler BUILD SUCCESSFUL Total time: 2 seconds