Enterprise JavaBeans, Fourth Edition

The ejbFind( ) Methods

In bean-managed persistence, the find methods in the remote or local home interface must match the ejbFind( ) methods in the actual bean class. In other words, for each method named find< SUFFIX >( ) in a home interface, there must be a corresponding ejbFind< SUFFIX >( ) method in the entity bean class with the same arguments and application exceptions. When a find method is invoked on an EJB home, the container delegates the find( ) method to a corresponding ejbFind( ) method on the bean instance. The bean-managed entity is responsible for locating records that match the find requests. There are two find methods in ShipHomeRemote:

public interface ShipHomeRemote extends javax.ejb.EJBHome {

    public ShipRemote findByPrimaryKey(Integer primaryKey) 
        throws FinderException, RemoteException;
    public Collection findByCapacity(int capacity) 
        throws FinderException, RemoteException;
}

Here are the signatures of the corresponding ejbFind( ) methods in the ShipBean:

public class ShipBean implements javax.ejb.EntityBean {

    public Integer ejbFindByPrimaryKey(Integer primaryKey) 
        throws FinderException {}
    public Collection ejbFindByCapacity(int capacity) 
        throws FinderException {}
}

Aside from the names, there’s a significant difference between these two groups of methods. The find methods in the home interface return either an EJB object implementing the bean’s remote interface—in this case, ShipRemote--or a collection of EJB objects in the form of a java.util.Enumeration or ...