Head First EJB

Writing the Remote home interface for a session bean

Now that you’ve seen the lookup and create process from the client’s point of view, we’ll see what you have to do to write a home interface for your bean. For session beans, the process is very easy. In fact, for stateless session beans, it’s ludicrously easy—you just declare a single, no-arg create() method.

package headfirst;

import javax.ejb.*;
import java.rmi.RemoteException;


public interface AdviceHome extends EJBHome {

  public Advice create() throws CreateException, RemoteException;

}

Rules for the home interface

1. Import javax.ejb.* and java.rmi.RemoteException.

2. Extend EJBHome.

3. Declare a create() method that returns the component interface and declares a CreateException and RemoteException

   • For stateless session beans, there can be only one create(), and it must NOT have arguments.

   • Stateful session beans can have multiple, overloaded create() methods, and do NOT need to have a no-arg create().

   • All create() methods must declare a CreateException and RemoteException, but they can also declare other application (checked) exceptions.

   • The name of create methods in stateful beans must begin with “create” (createAccount(), createBigDog(), createFashionAdvisor(), etc.).

   • For stateful session beans, arguments must be RMI-IIOP compatible (you know, Serializable, primtive, Remote, or arrays or collections of any of those).