Java/EJB3/Entity Inheritance

EJB Tutorial from JBoss: join inheritance

File: Cat.java
/*
 * JBoss, Home of Professional Open Source.
 * Copyright 2006, Red Hat Middleware LLC, and individual contributors
 * as indicated by the @author tags. See the copyright.txt file in the
 * distribution for a full listing of individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.jboss.tutorial.joininheritance.bean;
import javax.persistence.Entity;
import javax.persistence.Inheritance;
import javax.persistence.InheritanceType;
@Entity
@Inheritance(strategy = InheritanceType.JOINED)
public class Cat extends Pet
{
   int lives;
   public int getLives()
   {
      return lives;
   }
   public void setLives(int lives)
   {
      this.lives = lives;
   }
}

File: Dog.java
/*
 * JBoss, Home of Professional Open Source.
 * Copyright 2006, Red Hat Middleware LLC, and individual contributors
 * as indicated by the @author tags. See the copyright.txt file in the
 * distribution for a full listing of individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.jboss.tutorial.joininheritance.bean;
import javax.persistence.Entity;
import javax.persistence.Inheritance;
import javax.persistence.InheritanceType;
import javax.persistence.Inheritance;
import javax.persistence.InheritanceType;
import javax.persistence.Entity;
@Entity
@Inheritance(strategy = InheritanceType.JOINED)
public class Dog extends Pet
{
   private int numBones;
   public int getNumBones()
   {
      return numBones;
   }
   public void setNumBones(int numBones)
   {
      this.numBones = numBones;
   }
}

File: Pet.java
/*
 * JBoss, Home of Professional Open Source.
 * Copyright 2006, Red Hat Middleware LLC, and individual contributors
 * as indicated by the @author tags. See the copyright.txt file in the
 * distribution for a full listing of individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.jboss.tutorial.joininheritance.bean;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue; import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Inheritance;
import javax.persistence.GeneratedValue; import javax.persistence.GenerationType;
import javax.persistence.InheritanceType;
import javax.persistence.Entity;
@Entity
@Inheritance(strategy = InheritanceType.JOINED)
public class Pet implements java.io.Serializable
{
   private int id;
   private String name;
   private double weight;
   @Id @GeneratedValue(strategy=GenerationType.AUTO)
   public int getId()
   {
      return id;
   }
   public void setId(int id)
   {
      this.id = id;
   }
   public String getName()
   {
      return name;
   }
   public void setName(String name)
   {
      this.name = name;
   }
   public double getWeight()
   {
      return weight;
   }
   public void setWeight(double weight)
   {
      this.weight = weight;
   }
}

File: PetDAO.java
/*
 * JBoss, Home of Professional Open Source.
 * Copyright 2006, Red Hat Middleware LLC, and individual contributors
 * as indicated by the @author tags. See the copyright.txt file in the
 * distribution for a full listing of individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.jboss.tutorial.joininheritance.bean;
import java.util.List;
public interface PetDAO
{
   void createDog(String name, double weight, int bones);
   void createCat(String name, double weight, int lives);
   List findByWeight(double weight);
}

File: PetDAOBean.java
/*
 * JBoss, Home of Professional Open Source.
 * Copyright 2006, Red Hat Middleware LLC, and individual contributors
 * as indicated by the @author tags. See the copyright.txt file in the
 * distribution for a full listing of individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.jboss.tutorial.joininheritance.bean;
import java.util.List;
import javax.ejb.Remote;
import javax.ejb.Stateless;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import javax.persistence.PersistenceContext;
import javax.persistence.PersistenceContext;
@Stateless
@Remote(PetDAO.class)
public class PetDAOBean implements PetDAO
{
   @PersistenceContext
   private EntityManager manager;
   public void createDog(String name, double weight, int bones)
   {
      Dog dog = new Dog();
      dog.setName(name);
      dog.setWeight(weight);
      dog.setNumBones(bones);
      manager.persist(dog);
   }
   public void createCat(String name, double weight, int lives)
   {
      Cat cat = new Cat();
      cat.setName(name);
      cat.setWeight(weight);
      cat.setLives(lives);
      manager.persist(cat);
   }
   public List findByWeight(double weight)
   {
      return manager.createQuery("select p from Pet p where p.weight < :weight").setParameter("weight", weight).getResultList();
   }
}
File: Client.java
/*
 * JBoss, Home of Professional Open Source.
 * Copyright 2006, Red Hat Middleware LLC, and individual contributors
 * as indicated by the @author tags. See the copyright.txt file in the
 * distribution for a full listing of individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.jboss.tutorial.joininheritance.Client;
import org.jboss.tutorial.joininheritance.bean.Pet;
import org.jboss.tutorial.joininheritance.bean.PetDAO;
import javax.naming.InitialContext;
import java.util.List;
/**
 * Comment
 *
 * @author 



== EJB Tutorial from JBoss: single inheritance ==






   
  <!-- start source code -->
   
    <source lang="java">

File: Cat.java
/*
 * JBoss, Home of Professional Open Source.
 * Copyright 2006, Red Hat Middleware LLC, and individual contributors
 * as indicated by the @author tags. See the copyright.txt file in the
 * distribution for a full listing of individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.jboss.tutorial.singleinheritance.bean;
import javax.persistence.DiscriminatorType;
import javax.persistence.Entity;
import javax.persistence.Inheritance;
import javax.persistence.InheritanceType;
import javax.persistence.DiscriminatorColumn;
import javax.persistence.DiscriminatorValue;
@Entity
@Inheritance(strategy = InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn(discriminatorType = DiscriminatorType.STRING)
@DiscriminatorValue("CAT")
public class Cat extends Pet
{
   public String getHairball()
   {
      return hairball;
   }
   public void setHairball(String hairball)
   {
      this.hairball = hairball;
   }
   String hairball;
}

File: Dog.java
/*
 * JBoss, Home of Professional Open Source.
 * Copyright 2006, Red Hat Middleware LLC, and individual contributors
 * as indicated by the @author tags. See the copyright.txt file in the
 * distribution for a full listing of individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.jboss.tutorial.singleinheritance.bean;
import javax.persistence.DiscriminatorType;
import javax.persistence.Entity;
import javax.persistence.Inheritance;
import javax.persistence.InheritanceType;
import javax.persistence.DiscriminatorColumn;
import javax.persistence.DiscriminatorValue;
@Entity
@Inheritance(strategy = InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn(discriminatorType = DiscriminatorType.STRING)
@DiscriminatorValue("DOG")
public class Dog extends Pet
{
   private String trick;
   public String getTrick()
   {
      return trick;
   }
   public void setTrick(String trick)
   {
      this.trick = trick;
   }
}

File: Pet.java
/*
 * JBoss, Home of Professional Open Source.
 * Copyright 2006, Red Hat Middleware LLC, and individual contributors
 * as indicated by the @author tags. See the copyright.txt file in the
 * distribution for a full listing of individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.jboss.tutorial.singleinheritance.bean;
import javax.persistence.DiscriminatorColumn;
import javax.persistence.DiscriminatorType;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Inheritance;
import javax.persistence.InheritanceType;
@Entity
@Inheritance(strategy = InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn(name = "ANIMAL_TYPE", discriminatorType = DiscriminatorType.STRING)
public class Pet implements java.io.Serializable
{
   private int id;
   private String name;
   private double weight;
   @Id @GeneratedValue(strategy=GenerationType.AUTO)
   public int getId()
   {
      return id;
   }
   public void setId(int id)
   {
      this.id = id;
   }
   public String getName()
   {
      return name;
   }
   public void setName(String name)
   {
      this.name = name;
   }
   public double getWeight()
   {
      return weight;
   }
   public void setWeight(double weight)
   {
      this.weight = weight;
   }
}

File: PetDAO.java
/*
 * JBoss, Home of Professional Open Source.
 * Copyright 2006, Red Hat Middleware LLC, and individual contributors
 * as indicated by the @author tags. See the copyright.txt file in the
 * distribution for a full listing of individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.jboss.tutorial.singleinheritance.bean;
import java.util.List;
public interface PetDAO
{
   void createDog(String name, double weight, int bones);
   void createCat(String name, double weight, int lives);
   List findByWeight(double weight);
}

File: PetDAOBean.java
/*
 * JBoss, Home of Professional Open Source.
 * Copyright 2006, Red Hat Middleware LLC, and individual contributors
 * as indicated by the @author tags. See the copyright.txt file in the
 * distribution for a full listing of individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.jboss.tutorial.singleinheritance.bean;
import java.util.List;
import javax.ejb.Remote;
import javax.ejb.Stateless;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
@Stateless
@Remote(PetDAO.class)
public class PetDAOBean implements PetDAO
{
   @PersistenceContext
   private EntityManager manager;
   public void createDog(String name, double weight, int bones)
   {
      Dog dog = new Dog();
      dog.setName(name);
      dog.setWeight(weight);
      dog.setTrick("Sit");
      manager.persist(dog);
   }
   public void createCat(String name, double weight, int lives)
   {
      Cat cat = new Cat();
      cat.setName(name);
      cat.setWeight(weight);
      cat.setHairball("#$@#%@");
      manager.persist(cat);
   }
   public List findByWeight(double weight)
   {
      return manager.createQuery("select p from Pet p where p.weight < :weight").setParameter("weight", weight).getResultList();
   }
}

File: Client.java
/*
 * JBoss, Home of Professional Open Source.
 * Copyright 2006, Red Hat Middleware LLC, and individual contributors
 * as indicated by the @author tags. See the copyright.txt file in the
 * distribution for a full listing of individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.jboss.tutorial.singleinheritance.Client;

import org.jboss.tutorial.singleinheritance.bean.Pet;
import org.jboss.tutorial.singleinheritance.bean.PetDAO;
import javax.naming.InitialContext;
import java.util.List;
/**
 * Comment
 *
 * @author 



== Hierarchical entities ==






   
  <!-- start source code -->
   
    <source lang="java">
File: Employee.java
import javax.persistence.DiscriminatorColumn;
import javax.persistence.DiscriminatorType;
import javax.persistence.DiscriminatorValue;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Inheritance;
import javax.persistence.InheritanceType;
import javax.persistence.Table;

@Entity
public class Employee extends Customer {
   private int employeeId;
   public int getEmployeeId() { return employeeId; }
   public void setEmployeeId(int id) { employeeId = id; }
}

@Entity
@DiscriminatorValue("CUST")
class Customer extends Person {
   private String street;
   private String city;
   private String state;
   private String zip;
   
   public String getStreet() { return street; }
   public void setStreet(String street) { this.street = street; }
   public String getCity() { return city; }
   public void setCity(String city) { this.city = city; }
   public String getState() { return state; }
   public void setState(String state) { this.state = state; }
   public String getZip() { return zip; }
   public void setZip(String zip) { this.zip = zip; }
}

@Entity
@Table(name="PERSON_HIERARCHY")
@Inheritance(strategy=InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn(name="DISCRIMINATOR",
                     discriminatorType=DiscriminatorType.STRING)
@DiscriminatorValue("PERSON")
class Person implements java.io.Serializable
{
   private int id;
   private String firstName;
   private String lastName;
   @Id @GeneratedValue
   public int getId() { return id; }
   public void setId(int id) { this.id = id; }
   public String getFirstName() { return firstName; }
   public void setFirstName(String first) { this.firstName = first; }
   public String getLastName() { return lastName; }
   public void setLastName(String last) { this.lastName = last; }
}
    

File: EmployeeService.java

import javax.ejb.Stateless;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
@Stateless
public class EmployeeService implements EmployeeServiceLocal, EmployeeServiceRemote {
  @PersistenceContext(unitName="EmployeeService")
  EntityManager em;
  
  public EmployeeService() {
  }
  public void doAction(){
    Person p = new Person();
    p.setFirstName("P");
    p.setLastName("P");
    em.persist(p);
    Customer cust = new Customer();
    cust.setFirstName("C");
    cust.setLastName("C");
    cust.setStreet("Street");
    cust.setCity("City");
    cust.setState("State");
    cust.setZip("11111");
    em.persist(cust);
    Employee employee = new Employee();
    employee.setFirstName("E");
    employee.setLastName("E");
    employee.setStreet("1st Street");
    employee.setCity("E City");
    employee.setState("E State");
    employee.setZip("33333");
    employee.setEmployeeId(15);
    em.persist(employee);
    
    em.flush();
    System.out.println("saved");
    
  }
}
    

File: EmployeeServiceLocal.java

import java.util.Collection;
import javax.ejb.Local;
@Local
public interface EmployeeServiceLocal {
    public void doAction();
}

File: EmployeeServiceRemote.java


import java.util.Collection;
import javax.ejb.Remote;
@Remote
public interface EmployeeServiceRemote{
  public void doAction();  
}

File: jndi.properties
java.naming.factory.initial=org.jnp.interfaces.NamingContextFactory
java.naming.factory.url.pkgs=org.jboss.naming:org.jnp.interfaces
java.naming.provider.url=localhost:1099

File: Main.java
import java.util.Collection;
import javax.naming.InitialContext;

public class Main {
  public static void main(String[] a) throws Exception {
    EmployeeServiceRemote service = null;
    // Context compEnv = (Context) new InitialContext().lookup("java:comp/env");
    // service = (HelloService)new InitialContext().lookup("java:comp/env/ejb/HelloService");
    service = (EmployeeServiceRemote) new InitialContext().lookup("EmployeeService/remote");
    
    
    
    
    service.doAction();
  }
}

Inheritance Type: SINGLE_TABLE

File: Employee.java
import javax.persistence.DiscriminatorColumn;
import javax.persistence.DiscriminatorType;
import javax.persistence.DiscriminatorValue;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Inheritance;
import javax.persistence.InheritanceType;
import javax.persistence.Table;

@Entity
public class Employee extends Customer {
   private int employeeId;
   public int getEmployeeId() { return employeeId; }
   public void setEmployeeId(int id) { employeeId = id; }
}

@Entity
@DiscriminatorValue("CUST")
class Customer extends Person {
   private String street;
   private String city;
   private String state;
   private String zip;
   
   public String getStreet() { return street; }
   public void setStreet(String street) { this.street = street; }
   public String getCity() { return city; }
   public void setCity(String city) { this.city = city; }
   public String getState() { return state; }
   public void setState(String state) { this.state = state; }
   public String getZip() { return zip; }
   public void setZip(String zip) { this.zip = zip; }
}

@Entity
@Table(name="PERSON_HIERARCHY")
@Inheritance(strategy=InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn(name="DISCRIMINATOR",
                     discriminatorType=DiscriminatorType.STRING)
@DiscriminatorValue("PERSON")
class Person implements java.io.Serializable
{
   private int id;
   private String firstName;
   private String lastName;
   @Id @GeneratedValue
   public int getId() { return id; }
   public void setId(int id) { this.id = id; }
   public String getFirstName() { return firstName; }
   public void setFirstName(String first) { this.firstName = first; }
   public String getLastName() { return lastName; }
   public void setLastName(String last) { this.lastName = last; }
}
    

File: EmployeeService.java

import javax.ejb.Stateless;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
@Stateless
public class EmployeeService implements EmployeeServiceLocal, EmployeeServiceRemote {
  @PersistenceContext(unitName="EmployeeService")
  EntityManager em;
  
  public EmployeeService() {
  }
  public void doAction(){
    Person p = new Person();
    p.setFirstName("P");
    p.setLastName("P");
    em.persist(p);
    Customer cust = new Customer();
    cust.setFirstName("C");
    cust.setLastName("C");
    cust.setStreet("Street");
    cust.setCity("City");
    cust.setState("State");
    cust.setZip("11111");
    em.persist(cust);
    Employee employee = new Employee();
    employee.setFirstName("E");
    employee.setLastName("E");
    employee.setStreet("1st Street");
    employee.setCity("E City");
    employee.setState("E State");
    employee.setZip("33333");
    employee.setEmployeeId(15);
    em.persist(employee);
    
    em.flush();
    System.out.println("saved");
    
  }
}
    

File: EmployeeServiceLocal.java

import java.util.Collection;
import javax.ejb.Local;
@Local
public interface EmployeeServiceLocal {
    public void doAction();
}

File: EmployeeServiceRemote.java


import java.util.Collection;
import javax.ejb.Remote;
@Remote
public interface EmployeeServiceRemote{
  public void doAction();  
}

File: jndi.properties
java.naming.factory.initial=org.jnp.interfaces.NamingContextFactory
java.naming.factory.url.pkgs=org.jboss.naming:org.jnp.interfaces
java.naming.provider.url=localhost:1099

File: Main.java
import java.util.Collection;
import javax.naming.InitialContext;

public class Main {
  public static void main(String[] a) throws Exception {
    EmployeeServiceRemote service = null;
    // Context compEnv = (Context) new InitialContext().lookup("java:comp/env");
    // service = (HelloService)new InitialContext().lookup("java:comp/env/ejb/HelloService");
    service = (EmployeeServiceRemote) new InitialContext().lookup("EmployeeService/remote");
    
    
    
    
    service.doAction();
  }
}

Retrieve Hierarchical Entities

File: Employee.java
import javax.persistence.DiscriminatorColumn;
import javax.persistence.DiscriminatorType;
import javax.persistence.DiscriminatorValue;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Inheritance;
import javax.persistence.InheritanceType;
import javax.persistence.Table;

@Entity
public class Employee extends Customer {
   private int employeeId;
   public int getEmployeeId() { return employeeId; }
   public void setEmployeeId(int id) { employeeId = id; }
}

@Entity
@DiscriminatorValue("CUST")
class Customer extends Person {
   private String street;
   private String city;
   private String state;
   private String zip;
   
   public String getStreet() { return street; }
   public void setStreet(String street) { this.street = street; }
   public String getCity() { return city; }
   public void setCity(String city) { this.city = city; }
   public String getState() { return state; }
   public void setState(String state) { this.state = state; }
   public String getZip() { return zip; }
   public void setZip(String zip) { this.zip = zip; }
}

@Entity
@Table(name="PERSON_HIERARCHY")
@Inheritance(strategy=InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn(name="DISCRIMINATOR",
                     discriminatorType=DiscriminatorType.STRING)
@DiscriminatorValue("PERSON")
class Person implements java.io.Serializable
{
   private int id;
   private String firstName;
   private String lastName;
   @Id @GeneratedValue
   public int getId() { return id; }
   public void setId(int id) { this.id = id; }
   public String getFirstName() { return firstName; }
   public void setFirstName(String first) { this.firstName = first; }
   public String getLastName() { return lastName; }
   public void setLastName(String last) { this.lastName = last; }
}
    

File: EmployeeService.java

import java.util.List;
import javax.ejb.Stateless;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
@Stateless
public class EmployeeService implements EmployeeServiceLocal, EmployeeServiceRemote {
  @PersistenceContext(unitName="EmployeeService")
  EntityManager em;
  
  public EmployeeService() {
  }
  public void doAction(){
    Person p = new Person();
    p.setFirstName("P");
    p.setLastName("P");
    em.persist(p);
    Customer cust = new Customer();
    cust.setFirstName("C");
    cust.setLastName("C");
    cust.setStreet("Street");
    cust.setCity("City");
    cust.setState("State");
    cust.setZip("11111");
    em.persist(cust);
    Employee employee = new Employee();
    employee.setFirstName("E");
    employee.setLastName("E");
    employee.setStreet("1st Street");
    employee.setCity("E City");
    employee.setState("E State");
    employee.setZip("33333");
    employee.setEmployeeId(15);
    em.persist(employee);
    
    em.flush();
    System.out.println("saved");
    
    
    List list = em.createQuery("FROM Person p").getResultList();
    
    
  }
}
    

File: EmployeeServiceLocal.java

import java.util.Collection;
import javax.ejb.Local;
@Local
public interface EmployeeServiceLocal {
    public void doAction();
}

File: EmployeeServiceRemote.java


import java.util.Collection;
import javax.ejb.Remote;
@Remote
public interface EmployeeServiceRemote{
  public void doAction();  
}

File: jndi.properties
java.naming.factory.initial=org.jnp.interfaces.NamingContextFactory
java.naming.factory.url.pkgs=org.jboss.naming:org.jnp.interfaces
java.naming.provider.url=localhost:1099

File: Main.java
import java.util.Collection;
import javax.naming.InitialContext;

public class Main {
  public static void main(String[] a) throws Exception {
    EmployeeServiceRemote service = null;
    // Context compEnv = (Context) new InitialContext().lookup("java:comp/env");
    // service = (HelloService)new InitialContext().lookup("java:comp/env/ejb/HelloService");
    service = (EmployeeServiceRemote) new InitialContext().lookup("EmployeeService/remote");
    
    
    
    
    service.doAction();
  }
}