Enterprise JavaBeans, Fourth Edition

Exercise 6.3: A Simple Relationship in CMP 2.0

The example program in Exercise 6.3 shows how to implement a simple CMP relationship between the Customer EJB and the Address EJB. The client again uses dependent value classes, to pass address information along to the Customer EJB.

Build and Deploy the Example Programs

Perform the following steps:

1. Open a command prompt or shell terminal and change to the ex06_3 directory created by the extraction process.

2. Set the JAVA_HOME and JBOSS_HOME environment variables to point to where your JDK and JBoss 4.0 are installed. Examples:

   Windows:C:\workbook\ex06_3> set JAVA_HOME=C:\jdk1.4.2 C:\workbook\ex06_3> set JBOSS_HOME=C:\jboss-4.0

   Unix:$ export JAVA_HOME=/usr/local/jdk1.4.2 $ export JBOSS_HOME=/usr/local/jboss-4.0

3. Add ant to your execution path.

   Windows:C:\workbook\ex06_3> set PATH=..\ant\bin;%PATH%

   Unix:$ export PATH=../ant/bin:$PATH

4. Perform the build by typing ant.

As in the last exercise, you will see titan.jar rebuilt, copied to the JBoss deploy directory, and redeployed by the application server.

Examine the JBoss-Specific Files

The Customer-Address relationship in this example can be mapped to a database table by defining the mapping in jbosscmp-jdbc.xml.

jbosscmp-jdbc.xml

<jbosscmp-jdbc> ... </enterprise-beans> <relationships> <ejb-relation> <ejb-relation-name>Customer-Address</ejb-relation-name> <foreign-key-mapping/> <ejb-relationship-role> <ejb-relationship-role-name>Customer-has-a-Address </ejb-relationship-role-name> <key-fields/> </ejb-relationship-role> ...