CMP bean with auto-increment ID as primary key

[nitesh]

Hello,

I'm developing a CMP entity bean and I want to have an auto-increment identity column of the database table as the primary-key. Can this be done? How do I specify this in the ejb-jar.xml and jaws.xml?

Thanks,

Nitesh

[davidjencks]

No it can't. This is one of the most frequently asked questions, you can find many viewpoints in the forum.

[nathanf]

Here's what I did.

I used "JBossUtilAutoNumber" which is located at org.jboss.util.AutoNumberFactory.

In your ejb-jar.xml put:


<ejb-name>JBossUtilAutoNumber</ejb-name>
org.jboss.util.AutoNumberHome
org.jboss.util.AutoNumber
<ejb-class>org.jboss.util.AutoNumberEJB</ejb-class>
<persistence-type>Container</persistence-type>
<prim-key-class>java.lang.String</prim-key-class>
True
<cmp-field><field-name>name</field-name></cmp-field>
<cmp-field><field-name>value</field-name></cmp-field>
<primkey-field>name</primkey-field>


In jaws.xml:


<ejb-name>JBossUtilAutoNumber</ejb-name>
<table-name>JBossUtilAutoNumberEJBTable</table-name>
<create-table>true</create-table>
<remove-table>false</remove-table>
<tuned-updates>true</tuned-updates>
<read-only>false</read-only>
<time-out>300</time-out>
<cmp-field>
<field-name>name</field-name>
<column-name>name</column-name>
<sql-type>VARCHAR(30)</sql-type>
<jdbc-type>VARCHAR</jdbc-type>
</cmp-field>
<cmp-field>
<field-name>value</field-name>
<column-name>value</column-name>
</cmp-field>



In your actual EJB (not any of the interfaces), import org.jboss.util.AutoNumberFactory.

Then in the ejbCreate method:

id = AutoNumberFactory.getNextInteger("nameofbean");

Just remember to have id as a member variable of your bean.

So far this method has been working perfectly and performance has been great.

[cincaipatron]

http://www.theserverside.com/patterns/index.jsp
http://sourceforge.net/projects/ejbutils/

[garymarsh]

nathanf;

I have attempted to use your suggestion in my CMP Entity Bean project but when I startup the JBoss server I get the following message:

------------

[Container factory] Deploying JBossUtilAutoNumber
[Container factory] Deploying Client
[Container factory] Deploying Employee
[JAWS] Table 'JBossUtilAutoNumberEJBTable' already exists
[Container factory] java.lang.NoSuchMethodException
[Container factory] at java.lang.Class.getMethod0(Native Method)
[Container factory] at java.lang.Class.getMethod(Class.java:888)
[Container factory] at org.jboss.ejb.plugins.CMPPersistenceManager.createMethodCache(CMPPersistenceManager.java:122)
[Container factory] at org.jboss.ejb.plugins.CMPPersistenceManager.init(CMPPersistenceManager.java:102)
[Container factory] at org.jboss.ejb.EntityContainer.init(EntityContainer.java:291)
[Container factory] at org.jboss.ejb.Application.init(Application.java:202)
[Container factory] at org.jboss.ejb.ContainerFactory.deploy(ContainerFactory.java:372)
[Container factory] at org.jboss.ejb.ContainerFactory.deploy(ContainerFactory.java:304)
[Container factory] at java.lang.reflect.Method.invoke(Native Method)
[Container factory] at com.sun.management.jmx.MBeanServerImpl.invoke(MBeanServerImpl.java:1628)
[Container factory] at com.sun.management.jmx.MBeanServerImpl.invoke(MBeanServerImpl.java:1523)
[Container factory] at org.jboss.deployment.J2eeDeployer.startModules(J2eeDeployer.java:494)
[Container factory] at org.jboss.deployment.J2eeDeployer.startApplication(J2eeDeployer.java:468)
[Container factory] at org.jboss.deployment.J2eeDeployer.deploy(J2eeDeployer.java:208)
[Container factory] at java.lang.reflect.Method.invoke(Native Method)
[Container factory] at com.sun.management.jmx.MBeanServerImpl.invoke(MBeanServerImpl.java:1628)
[Container factory] at com.sun.management.jmx.MBeanServerImpl.invoke(MBeanServerImpl.java:1523)
[Container factory] at org.jboss.ejb.AutoDeployer.deploy(AutoDeployer.java:379)
[Container factory] at org.jboss.ejb.AutoDeployer.run(AutoDeployer.java:217)
[Container factory] at java.lang.Thread.run(Thread.java:484)
[J2EE Deployer Default] Starting Paye_Payroll-20011228.jar failed!

-----------------------

I am not sure from the message whether the problem is with the auto numbering or if it is something else. Is the message :

[JAWS] Table 'JBossUtilAutoNumberEJBTable' already exists

normal after the first time you start the server??

Gary