31.6.8. BMP Custom Finders

JBoss also supports bean managed persistence custom finders. If a custom finder method matches a finder declared in the home or local home interface, JBoss will always call the custom finder over any other implementation declared in the ejb-jar.xml or jbosscmp-jdbc.xml files. The following simple example finds the entities by a collection of primary keys:

public abstract class GangsterBean
    implements EntityBean 
{
    public Collection ejbFindByPrimaryKeys(Collection keys)
    {
        return keys;
    }
}

public abstract class GangsterBean
    implements EntityBean 
{
    public Collection ejbFindByPrimaryKeys(Collection keys)
    {
        return keys;
    }
}

This is a very useful finder because it quickly coverts primary keys into real Entity objects without contacting the database. One drawback is that it can create an Entity object with a primary key that does not exist in the database. If any method is invoked on the bad Entity, a NoSuchEntityException will be thrown. Another drawback is that the resulting entity bean violates the EJB specification in that it implements a finder, and the JBoss EJB verifier will fail the deployment of such an entity unless the StrictVerifier attribute is set to false.