Re: Entity EJB3 Example with Hibernate as persistance Layer

[leonell]

Hello,
you cannot obtain entity bean (XText) directly.
You must create session bean and remote interface.
Then in session bean you can use EntityManager to obtain (persist, remove,..) entity beans.
From client you ask remote interface of this session bean and call its method (and obtain detached entity bean or if you want, DTOs ).

See tutorial of JBOSS EJB3 distribution.

Leonell

[sanjaya5]

RTFM, my friend :}

[sanjaya5]

Hey, I'm using San's accout for posting, becouse I get only exception if I want to register.

OK, I created a Remote Interface and a Stateful Session Bean. If I want to access to the Remote Interface I get only $proxy[64|63|74|...] so I get a TypeCastException.
client

...
public String getResult() {
 System.out.println("Bitch");
 try {
 InitialContext ctx = new InitialContext();
 System.out.println(XText.class.getName());
 XText xtext = (XText) ctx.lookup(XText.class.getName()); // Type Cast Exception
 /*xtext.sayHello();
 System.out.println("Hello World");*/
 return XText.class.getName();
 }catch(NamingException e){
 e.printStackTrace();
 return "Hello";
 }
 }...

RemoteInterface

package de.anwend.ejb;

import javax.ejb.Remote;
import javax.ejb.Remove;

@Remote
public interface XText
{
 void setText(String text);
 String getText();
 @Remove void remove();
 void sayHello();
}

Stateful Bean

package de.anwend.ejb;
import javax.ejb.Remove;
import javax.ejb.Stateful;
import javax.persistence.EntityManager;


@Stateful
public class XTextBean implements XText
{
 private EntityManager manager;
 private XTextEntity xtext;

 public void setText(String text) {
 if(xtext == null) xtext = new XTextEntity();
 xtext.setText(text);
 }

 public String getText() {
 return xtext.getText();
 }

 public void sayHello() {
 System.out.println("Hello fucking world");
 }

 @Remove
 public void remove()
 {
 manager.persist(xtext);
 }
}

Entity Bean

package de.anwend.ejb;

import java.io.Serializable;

import javax.persistence.GeneratorType;
import javax.persistence.Id;
import javax.persistence.Table;

import org.hibernate.annotations.Entity;

@Entity
@Table(name = "xyz")
public class XTextEntity implements Serializable{
 private Long id;
 private String text;

 @Id(generate = GeneratorType.AUTO)
 public Long getId() {
 return id;
 }

 public void setId(Long id) {
 this.id = id;
 }

 public String getText() {
 return text;
 }

 public void setText(String text) {
 this.text = text;
 }
}

Exception

javax.servlet.ServletException: javax.servlet.jsp.JspException: javax.faces.el.EvaluationException: Error getting property 'result' from bean of type de.anwend.bean.Ausgabe: java.lang.ClassCastException: $Proxy63

Regards
Michael Ernst

PS: Yes, he knows, that I'm using his account

[leonell]

Michael,
in Topic "Problem with removing item from collection in detached object" is example of EJB3 application (EB, SB, interface and client) for 1:N mapping.
Use it as base for your application.

In your code are at least these errors:
- you dont inject Entity manager (@Inject, @PersistenceContext in Beta)
- you don't work with EB (see find, persist, merge method of EntityManager).

You also use org.hibernate.annotations.Entity instead javax.persistence.Entity (I dont know if here is some difference).

If problem still occurs then undeploy your ejb3 project and deploy it again and check server.log for ERROR.

Leonell

[sanjaya5]

OK, thanks!

I don't want to use, your Bean becouse I think it's a little bit to complicated to be an easy example of EJB3.
I deleted my XText.ejb3 from the server.
Now I have copied the entity Bean example of jboss (jboss-EJB-3.0_Preview_5\docs\tutorial\entity). I also copied the cliend's code to the managed Bean. If I deploy the whole example it looks very well becouse tables are createt and so on. But if is start the Client I get the same error message

 InitialContext ctx = new InitialContext();
 ShoppingCart cart = (ShoppingCart) ctx.lookup(ShoppingCart.class.getName()); // Exception

2005-06-26 12:50:38,543 DEBUG [com.sun.faces.el.ValueBindingImpl] getValue(ref=ausgabe.result)
2005-06-26 12:50:38,663 DEBUG [com.sun.faces.application.ApplicationImpl] Created bean ausgabe successfully
2005-06-26 12:50:38,663 DEBUG [com.sun.faces.application.ApplicationImpl] Storing ausgabe in scope request
2005-06-26 12:50:38,663 DEBUG [com.sun.faces.el.VariableResolverImpl] resolveVariable: Resolved variable:de.anwend.bean.Ausgabe@1125a40
2005-06-26 12:50:38,863 DEBUG [javax.faces.el.PropertyResolver] Error getting property 'result' from bean of type de.anwend.bean.Ausgabe: java.lang.ClassCastException: $Proxy70
java.lang.ClassCastException: $Proxy70
 at de.anwend.bean.Ausgabe.getResult(Ausgabe.java:18)
 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

What can I do to get a running example! I don't think that ist very difficult. Why I get a $proxy and not the RemoteInterface?

Regards
Michael Ernst

[leonell]

Michael,
I don't know if this is solution of your problem but check if you have all needed JAR files in your client classpath (and in correct version ).

I use the following packages (Beta1 - I mean but for Preview 5 was the same packages):

commons-logging-api.jar
commons-logging.jar
jboss-ejb3.jar
jboss-ejb3x.jar
jboss-aop-jdk50.jar
jbossall-client.jar
jboss-aspect-library-jdk50.jar
hibernate3.jar
hibernate-metadata.jar
ejb3-persistence.jar
hibernate-entitymanager.jar
jaxen-1.1-beta-4.jar
jboss-remoting.jar

You can found all these libraries in your JBOSS distribution.

Not all are needed * !!!

* But it works for me and I don't have reason to search their subset for now...

Hope it helps.

Leonell