Trying to use EntityHome

[iklein99]

I'm trying to do a very simple "hello world" where I'm using an extended version EntityHome (which is created by the Eclipse plugin.

I have an EJB that instantiates this extended Entity, gets the instance, sets a field, and calls persist().  The result is that the entity is persisted, but it also crashes with a Null Pointer along the way.

Here is the extended EntityHome:


@Entity
@Name("person")
public class Person implements Serializable
{
    /**
         *
         */
        private static final long serialVersionUID = 1L;
        // seam-gen attributes (you should probably edit these)
    private Long id;
    private String name;

    // add additional entity attributes

    // seam-gen attribute getters/setters with annotations (you probably should edit)

    @Id @GeneratedValue
    public Long getId() {
        return id;
    }

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

    @Length(max = 20)
    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

}


Here is the bean that uses it...


     public void sayHello(String name)
    {
         PersonHome personHome = new PersonHome();
        
        
        // implement your business logic here
        log.info("Hello.sayHello() action called with: #{person.name}");
        statusMessages.add("sayHello #{person.name}");
       
         Person p = (Person) personHome.getInstance();
         p.setName(name);
         personHome.persist();
         ...

Here is the stack trace...

Caused by: java.lang.NullPointerException
        at org.jboss.seam.framework.Controller.debug(Controller.java:197)
        at org.jboss.seam.framework.Home.updatedMessage(Home.java:54)
        at org.jboss.seam.framework.EntityHome.update(EntityHome.java:65)
        at org.domain.helloworld2.session.HelloBean.sayHello(HelloBean.java:47)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)

[vata2999]

as i know while you're using @Name annotation in your entity class you don't need to use EntityHome if you want to use entityHome put @Name annotation in your EntityHome
in addition to get component instance use this

Person p = (Person) Component.getInstance("person");

[lvdberg]

Hi,

This happens because you're not using the bean correctly (because you're constructing it yourself). When you try to print (log.info) it will find a not-injected log-instance, which results in your NPE.

Leo