EJB Tutorial from JBoss: single inheritance : Entity Inheritance « EJB3 « Java

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2. EJB3
3. Entity Inheritance

EJB Tutorial from JBoss: single 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.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 <a href="mailto:bill@jboss.org">Bill Burke</a>
 * @version $Revision: 57207 $
 */
public class Client
{
   public static void main(String[] args) throws Exception
   {
      InitialContext ctx = new InitialContext();
      PetDAO dao = (PetDAO) ctx.lookup("PetDAOBean/remote");

      dao.createCat("Toonses", 15.0, 9);
      dao.createCat("Sox", 10.0, 5);
      dao.createDog("Winnie", 70.0, 5);
      dao.createDog("Junior", 11.0, 1);

      List l = dao.findByWeight(14.0);
      for (Object o : l)
      {
         System.out.println(((Pet) o).getName());
      }
   }
}




           
       

jboss-EJB-3.0_RC9_Patch_1.zip( 10,289 k)

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