/**
 * 
 */
package jpa;

import javax.annotation.PreDestroy;
import javax.enterprise.context.ApplicationScoped;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;

/**
 * A singleton for application wide {@link EntityManagerFactory}. Increases
 * performance significant.
 *
 * @author Stefan Suhren
 * @version 1.0
 */
@ApplicationScoped
public class EntityManagerFactorySingleton
{
   private static final String DB_PU = "catalog";

   private static final EntityManagerFactorySingleton singleton = new EntityManagerFactorySingleton();

   private EntityManagerFactory emf;

   private EntityManagerFactorySingleton()
   {
   }

   public static EntityManagerFactorySingleton getInstance()
   {
      return singleton;
   }

   public EntityManagerFactory getEntityManagerFactory()
   {
      if (emf == null)
      {
         emf = Persistence.createEntityManagerFactory(DB_PU);
      }
      return emf;
   }

   @PreDestroy
   public void closeEmf()
   {
      if (emf != null && emf.isOpen())
      {
         emf.close();
      }
      emf = null;
   }
}