Inheritance, Polymorphism, and Butler with no eyebrows.
So for latest plea for help, I have a superclass entity (Animal), and two subclass entities (Dog, Cat) and an inheritance problem. The problem I have is in a stateful bean very similar to the example 'Messages' except mine is called "findAnimalLikeNameBean", and it runs queries on generalized animals. The problem I have with the following example is that the animal never gets outjected to the Animal field in my "findAnimalLikeNameBean", Please note the (//THIS ALWAYS RETURNS NULL") in the last code snippet of this post. I think I did a pretty good job scouring stuff to see what I did wrong but couldn't find anything (yet). Are there special cicumstances concerning inheritance and polymorphism?
@Entity(name="Animal")
@Table(name="ag_animal")
@Inheritance(strategy = InheritanceType.JOINED)
@Name(value="animal")
@Scope(value=ScopeType.SESSION)
public class Animal implements Serializable {
....
}
@Entity(name="Cat")
@Table(name="ag_cat")
@Inheritance(strategy = InheritanceType.JOINED)
@Name(value="cat")
public class Cat extends Animal implements Serializable {
....
}
@Entity(name="Dog")
@Table(name="ag_dog")
@Inheritance(strategy = InheritanceType.JOINED)
@Name(value="dog")
public class Dog extends Animal implements Serializable {
....
}
@Stateful
@Name(value="findAnimalsLikeNameBean")
@Scope(value=ScopeType.SESSION)
public class FindAnimalsLikeNameBean extends AnimalQueryBean
implements FindAnimalsLikeNameLocal{
@PersistenceContext(unitName="mypets",
type=PersistenceContextType.EXTENDED)
private EntityManager entityManager;
private String name;
public void setName(String name) {
this.name = name;
}
public String getName() {
return name;
}
// public void setAnimal(Animal animal) {
// this.animal = animal;
// }
//
// public Animal getAnimal() {
// return animal;
// }
@DataModel
private List<Animal> animalList;
@DataModelSelection @Out
private Animal animal;
@Logger
private Log log;
public void setAnimalList(List<Animal> animalList) {
this.animalList = animalList;
}
public List<Animal> getAnimalList() {
return animalList;
}
public String execute() {
animalList = findLikeName(getName());
return "Success";
}
@TransactionAttribute(value=TransactionAttributeType.REQUIRED)
public List<Animal> findLikeName(String name) {
String queryString = "SELECT p FROM Animal p " +
"WHERE UPPER(p.name) LIKE UPPER(:name)) " +
"ORDER BY p.name ASC";
Query query = entityManager.createQuery(queryString);
query.setParameter("name", '%' + name + '%');
return createAnimalList(query.getResultList());
}
public String select() {
System.out.println(">>" + animal); //THIS ALWAYS RETURNS NULL
if (animal != null) {
if (animal instanceof Dog {
return "Dog";
}
if (animal instanceof Cat) {
return "Cat";
}
}
return "Success";
}
@Remove @Destroy
public void destroy() {}
}
