In EJB 3.0, your bean's interfaces are not required to extend any specific set of interfaces and generally have no requirements on them at all. These are referred to in EJB spec lingo as Business Interfaces.
In EJB 2.1 and prior, however, there were some pretty strict requirements on interfaces. Namely, you had to have a "home" interface that extended javax.ejb.EJBHome or javax.ejb.EJBLocalHome. This interface served as a sort of factory to create your bean's interface which itself had to extend either javax.ejb.EJBObject or javax.ejb.EJBLocalObject. These legacy styles of interfaces in EJB spec lingo are referred to as Component Interfaces.
In this example we see how one can support both business interfaces and component interfaces on the same bean. You may choose to do this for backwards compatibility with older clients or to maintain an older EJB 2.x API still being used. The advantage is that you can turn EJB 2.1 beans into EJB 3.0 beans without having to update any code consuming that EJB.
Source available in svn.
package org.superbiz;
import javax.ejb.Init;
import javax.ejb.Local;
import javax.ejb.LocalHome;
import javax.ejb.Remote;
import javax.ejb.RemoteHome;
import javax.ejb.Remove;
import javax.ejb.Stateful;
import java.text.MessageFormat;
import java.util.HashMap;
import java.util.Locale;
import java.util.Properties;
/**
* This is an EJB 3 style pojo stateful session bean
* it does not need to implement javax.ejb.SessionBean
*
* @author <a href="mailto:david.blevins@visi.com">David Blevins</a>
*/
//START SNIPPET: code
// EJB 3.0 Style business interfaces
// Each of these interfaces are already annotated in the classes
// themselves with @Remote and @Local, so annotating them here
// in the bean class again is not really required.
@Remote({FriendlyPersonRemote.class})
@Local({FriendlyPersonLocal.class})
// EJB 2.1 Style component interfaces
// These interfaces, however, must be annotated here in the bean class.
// Use of @RemoteHome in the FriendlyPersonEjbHome class itself is not allowed.
// Use of @LocalHome in the FriendlyPersonEjbLocalHome class itself is also not allowed.
@RemoteHome(FriendlyPersonEjbHome.class)
@LocalHome(FriendlyPersonEjbLocalHome.class)
@Stateful
public class FriendlyPerson implements FriendlyPersonLocal, FriendlyPersonRemote {
private final HashMap<String, MessageFormat> greetings;
private final Properties languagePreferences;
private String defaultLanguage;
public FriendlyPerson() {
greetings = new HashMap();
languagePreferences = new Properties();
defaultLanguage = Locale.getDefault().getLanguage();
addGreeting("en", "Hello {0}!");
addGreeting("es", "Hola {0}!");
addGreeting("fr", "Bonjour {0}!");
addGreeting("pl", "Witaj {0}!");
}
/**
* This method corresponds to the FriendlyPersonEjbHome.create() method
* and the FriendlyPersonEjbLocalHome.create()
* <p/>
* If you do not have an EJBHome or EJBLocalHome interface, this method
* can be deleted.
*/
@Init
public void create() {
}
/**
* This method corresponds to the following methods:
* - EJBObject.remove()
* - EJBHome.remove(ejbObject)
* - EJBLocalObject.remove()
* - EJBLocalHome.remove(ejbObject)
* <p/>
* If you do not have an EJBHome or EJBLocalHome interface, this method
* can be deleted.
*/
@Remove
public void remove() {
}
public String greet(String friend) {
String language = languagePreferences.getProperty(friend, defaultLanguage);
return greet(language, friend);
}
public String greet(String language, String friend) {
MessageFormat greeting = greetings.get(language);
if (greeting == null) {
Locale locale = new Locale(language);
return "Sorry, I don't speak " + locale.getDisplayLanguage() + ".";
}
return greeting.format(new Object[]{friend});
}
public void addGreeting(String language, String message) {
greetings.put(language, new MessageFormat(message));
}
public void setLanguagePreferences(String friend, String language) {
languagePreferences.put(friend, language);
}
public String getDefaultLanguage() {
return defaultLanguage;
}
public void setDefaultLanguage(String defaultLanguage) {
this.defaultLanguage = defaultLanguage;
}
}
package org.superbiz;
//START SNIPPET: code
import javax.ejb.CreateException;
import javax.ejb.EJBHome;
import java.rmi.RemoteException;
public interface FriendlyPersonEjbHome extends EJBHome {
FriendlyPersonEjbObject create() throws CreateException, RemoteException;
}
package org.superbiz;
//START SNIPPET: code
import javax.ejb.CreateException;
import javax.ejb.EJBLocalHome;
import java.rmi.RemoteException;
public interface FriendlyPersonEjbLocalHome extends EJBLocalHome {
FriendlyPersonEjbLocalObject create() throws CreateException, RemoteException;
}
package org.superbiz;
import javax.ejb.EJBLocalObject;
public interface FriendlyPersonEjbLocalObject extends EJBLocalObject {
String greet(String friend);
String greet(String language, String friend);
void addGreeting(String language, String message);
void setLanguagePreferences(String friend, String language);
String getDefaultLanguage();
void setDefaultLanguage(String defaultLanguage);
}
package org.superbiz;
//START SNIPPET: code
import javax.ejb.EJBObject;
import java.rmi.RemoteException;
public interface FriendlyPersonEjbObject extends EJBObject {
String greet(String friend) throws RemoteException;
String greet(String language, String friend) throws RemoteException;
void addGreeting(String language, String message) throws RemoteException;
void setLanguagePreferences(String friend, String language) throws RemoteException;
String getDefaultLanguage() throws RemoteException;
void setDefaultLanguage(String defaultLanguage) throws RemoteException;
}
package org.superbiz;
//START SNIPPET: code
import javax.ejb.Local;
@Local
public interface FriendlyPersonLocal {
String greet(String friend);
String greet(String language, String friend);
void addGreeting(String language, String message);
void setLanguagePreferences(String friend, String language);
String getDefaultLanguage();
void setDefaultLanguage(String defaultLanguage);
}
package org.superbiz;
import javax.ejb.Remote;
//START SNIPPET: code
@Remote
public interface FriendlyPersonRemote {
String greet(String friend);
String greet(String language, String friend);
void addGreeting(String language, String message);
void setLanguagePreferences(String friend, String language);
String getDefaultLanguage();
void setDefaultLanguage(String defaultLanguage);
}
package org.superbiz;
import junit.framework.TestCase;
import javax.ejb.embeddable.EJBContainer;
import javax.naming.Context;
import java.util.Locale;
/**
* @author <a href="mailto:david.blevins@visi.com">David Blevins</a>
* @version $Rev: 1090810 $ $Date: 2011-04-10 07:49:26 -0700 (Sun, 10 Apr 2011) $
*/
public class FriendlyPersonTest extends TestCase {
private Context context;
protected void setUp() throws Exception {
context = EJBContainer.createEJBContainer().getContext();
}
/**
* Here we lookup and test the FriendlyPerson bean via its EJB 2.1 EJBHome and EJBObject interfaces
*
* @throws Exception
*/
//START SNIPPET: remotehome
public void testEjbHomeAndEjbObject() throws Exception {
Object object = context.lookup("java:global/component-interfaces/FriendlyPerson!org.superbiz.FriendlyPersonEjbHome");
FriendlyPersonEjbHome home = (FriendlyPersonEjbHome) object;
FriendlyPersonEjbObject friendlyPerson = home.create();
friendlyPerson.setDefaultLanguage("en");
assertEquals("Hello David!", friendlyPerson.greet("David"));
assertEquals("Hello Amelia!", friendlyPerson.greet("Amelia"));
friendlyPerson.setLanguagePreferences("Amelia", "es");
assertEquals("Hello David!", friendlyPerson.greet("David"));
assertEquals("Hola Amelia!", friendlyPerson.greet("Amelia"));
// Amelia took some French, let's see if she remembers
assertEquals("Bonjour Amelia!", friendlyPerson.greet("fr", "Amelia"));
// Dave should take some Polish and if he had, he could say Hi in Polish
assertEquals("Witaj Dave!", friendlyPerson.greet("pl", "Dave"));
// Let's see if I speak Portuguese
assertEquals("Sorry, I don't speak " + new Locale("pt").getDisplayLanguage() + ".", friendlyPerson.greet("pt", "David"));
// Ok, well I've been meaning to learn, so...
friendlyPerson.addGreeting("pt", "Ola {0}!");
assertEquals("Ola David!", friendlyPerson.greet("pt", "David"));
}
//END SNIPPET: remotehome
/**
* Here we lookup and test the FriendlyPerson bean via its EJB 2.1 EJBLocalHome and EJBLocalObject interfaces
*
* @throws Exception
*/
public void testEjbLocalHomeAndEjbLocalObject() throws Exception {
Object object = context.lookup("java:global/component-interfaces/FriendlyPerson!org.superbiz.FriendlyPersonEjbLocalHome");
FriendlyPersonEjbLocalHome home = (FriendlyPersonEjbLocalHome) object;
FriendlyPersonEjbLocalObject friendlyPerson = home.create();
friendlyPerson.setDefaultLanguage("en");
assertEquals("Hello David!", friendlyPerson.greet("David"));
assertEquals("Hello Amelia!", friendlyPerson.greet("Amelia"));
friendlyPerson.setLanguagePreferences("Amelia", "es");
assertEquals("Hello David!", friendlyPerson.greet("David"));
assertEquals("Hola Amelia!", friendlyPerson.greet("Amelia"));
// Amelia took some French, let's see if she remembers
assertEquals("Bonjour Amelia!", friendlyPerson.greet("fr", "Amelia"));
// Dave should take some Polish and if he had, he could say Hi in Polish
assertEquals("Witaj Dave!", friendlyPerson.greet("pl", "Dave"));
// Let's see if I speak Portuguese
assertEquals("Sorry, I don't speak " + new Locale("pt").getDisplayLanguage() + ".", friendlyPerson.greet("pt", "David"));
// Ok, well I've been meaning to learn, so...
friendlyPerson.addGreeting("pt", "Ola {0}!");
assertEquals("Ola David!", friendlyPerson.greet("pt", "David"));
}
/**
* Here we lookup and test the FriendlyPerson bean via its EJB 3.0 business remote interface
*
* @throws Exception
*/
//START SNIPPET: remote
public void testBusinessRemote() throws Exception {
Object object = context.lookup("java:global/component-interfaces/FriendlyPerson!org.superbiz.FriendlyPersonRemote");
FriendlyPersonRemote friendlyPerson = (FriendlyPersonRemote) object;
friendlyPerson.setDefaultLanguage("en");
assertEquals("Hello David!", friendlyPerson.greet("David"));
assertEquals("Hello Amelia!", friendlyPerson.greet("Amelia"));
friendlyPerson.setLanguagePreferences("Amelia", "es");
assertEquals("Hello David!", friendlyPerson.greet("David"));
assertEquals("Hola Amelia!", friendlyPerson.greet("Amelia"));
// Amelia took some French, let's see if she remembers
assertEquals("Bonjour Amelia!", friendlyPerson.greet("fr", "Amelia"));
// Dave should take some Polish and if he had, he could say Hi in Polish
assertEquals("Witaj Dave!", friendlyPerson.greet("pl", "Dave"));
// Let's see if I speak Portuguese
assertEquals("Sorry, I don't speak " + new Locale("pt").getDisplayLanguage() + ".", friendlyPerson.greet("pt", "David"));
// Ok, well I've been meaning to learn, so...
friendlyPerson.addGreeting("pt", "Ola {0}!");
assertEquals("Ola David!", friendlyPerson.greet("pt", "David"));
}
//START SNIPPET: remote
/**
* Here we lookup and test the FriendlyPerson bean via its EJB 3.0 business local interface
*
* @throws Exception
*/
public void testBusinessLocal() throws Exception {
Object object = context.lookup("java:global/component-interfaces/FriendlyPerson!org.superbiz.FriendlyPersonLocal");
FriendlyPersonLocal friendlyPerson = (FriendlyPersonLocal) object;
friendlyPerson.setDefaultLanguage("en");
assertEquals("Hello David!", friendlyPerson.greet("David"));
assertEquals("Hello Amelia!", friendlyPerson.greet("Amelia"));
friendlyPerson.setLanguagePreferences("Amelia", "es");
assertEquals("Hello David!", friendlyPerson.greet("David"));
assertEquals("Hola Amelia!", friendlyPerson.greet("Amelia"));
// Amelia took some French, let's see if she remembers
assertEquals("Bonjour Amelia!", friendlyPerson.greet("fr", "Amelia"));
// Dave should take some Polish and if he had, he could say Hi in Polish
assertEquals("Witaj Dave!", friendlyPerson.greet("pl", "Dave"));
// Let's see if I speak Portuguese
assertEquals("Sorry, I don't speak " + new Locale("pt").getDisplayLanguage() + ".", friendlyPerson.greet("pt", "David"));
// Ok, well I've been meaning to learn, so...
friendlyPerson.addGreeting("pt", "Ola {0}!");
assertEquals("Ola David!", friendlyPerson.greet("pt", "David"));
}
}
-------------------------------------------------------
T E S T S
-------------------------------------------------------
Running org.superbiz.FriendlyPersonTest
Apache OpenEJB 4.0.0-beta-1 build: 20111002-04:06
http://tomee.apache.org/
INFO - openejb.home = /Users/dblevins/examples/component-interfaces
INFO - openejb.base = /Users/dblevins/examples/component-interfaces
INFO - Using 'javax.ejb.embeddable.EJBContainer=true'
INFO - Configuring Service(id=Default Security Service, type=SecurityService, provider-id=Default Security Service)
INFO - Configuring Service(id=Default Transaction Manager, type=TransactionManager, provider-id=Default Transaction Manager)
INFO - Found EjbModule in classpath: /Users/dblevins/examples/component-interfaces/target/classes
INFO - Beginning load: /Users/dblevins/examples/component-interfaces/target/classes
INFO - Configuring enterprise application: /Users/dblevins/examples/component-interfaces
INFO - Configuring Service(id=Default Stateful Container, type=Container, provider-id=Default Stateful Container)
INFO - Auto-creating a container for bean FriendlyPerson: Container(type=STATEFUL, id=Default Stateful Container)
INFO - Configuring Service(id=Default Managed Container, type=Container, provider-id=Default Managed Container)
INFO - Auto-creating a container for bean org.superbiz.FriendlyPersonTest: Container(type=MANAGED, id=Default Managed Container)
INFO - Enterprise application "/Users/dblevins/examples/component-interfaces" loaded.
INFO - Assembling app: /Users/dblevins/examples/component-interfaces
INFO - Jndi(name="java:global/component-interfaces/FriendlyPerson!org.superbiz.FriendlyPersonLocal")
INFO - Jndi(name="java:global/component-interfaces/FriendlyPerson!org.superbiz.FriendlyPersonRemote")
INFO - Jndi(name="java:global/component-interfaces/FriendlyPerson!org.superbiz.FriendlyPersonEjbLocalHome")
INFO - Jndi(name="java:global/component-interfaces/FriendlyPerson!org.superbiz.FriendlyPersonEjbHome")
INFO - Jndi(name="java:global/component-interfaces/FriendlyPerson")
INFO - Jndi(name="java:global/EjbModule803660549/org.superbiz.FriendlyPersonTest!org.superbiz.FriendlyPersonTest")
INFO - Jndi(name="java:global/EjbModule803660549/org.superbiz.FriendlyPersonTest")
INFO - Created Ejb(deployment-id=FriendlyPerson, ejb-name=FriendlyPerson, container=Default Stateful Container)
INFO - Created Ejb(deployment-id=org.superbiz.FriendlyPersonTest, ejb-name=org.superbiz.FriendlyPersonTest, container=Default Managed Container)
INFO - Started Ejb(deployment-id=FriendlyPerson, ejb-name=FriendlyPerson, container=Default Stateful Container)
INFO - Started Ejb(deployment-id=org.superbiz.FriendlyPersonTest, ejb-name=org.superbiz.FriendlyPersonTest, container=Default Managed Container)
INFO - Deployed Application(path=/Users/dblevins/examples/component-interfaces)
INFO - EJBContainer already initialized. Call ejbContainer.close() to allow reinitialization
INFO - EJBContainer already initialized. Call ejbContainer.close() to allow reinitialization
INFO - EJBContainer already initialized. Call ejbContainer.close() to allow reinitialization
Tests run: 4, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 1.444 sec
Results :
Tests run: 4, Failures: 0, Errors: 0, Skipped: 0