/**
    * Copyright 2008 WebPhotos
    *
    * Licensed under the Apache License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    *      http://www.apache.org/licenses/LICENSE-2.0
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package net.sf.webphotos.dao.jpa;
  
  import java.util.List;
  import javax.persistence.EntityManager;
  import javax.persistence.PersistenceContext;
  import javax.persistence.Query;
  import net.sf.webphotos.entity.HasID;
  
  /**
   *
   * @author Guilherme L A Silva
   */
  public class WebPhotosDAO<E extends HasID, I> {
  
      protected EntityManager entityManager;
      private Class<E> entityClass;
      private Class<I> keyClass;
  
      public WebPhotosDAO(Class<E> entityClass, Class<I> keyClass) {
          this.entityClass = entityClass;
          this.keyClass = keyClass;
      }
  
      /**
       * Workarround for a rapid migration from RowSet
       *
       * @param query
       * @return
       * @deprecated
       */
      @Deprecated
      public Query createNativeQuery(String query) {
          return entityManager.createNativeQuery(query);
      }
  
      public E findBy(I id) {
          return entityManager.find(this.entityClass, id);
      }
  
      public void save(E object) throws Exception {
          if (object.getId() != null && object.equals(entityManager.find(entityClass, object.getId()))) {
              entityManager.merge(object);
          } else {
              entityManager.persist(object);
          }
      }
  
      public void remove(E object) throws Exception {
          entityManager.remove(object);
          entityManager.flush();
      }
  
      /**
       * @return the entityManager
       */
      public EntityManager getEntityManager() {
          return entityManager;
      }
  
      /**
       * @param entityManager the entityManager to set
       */
      @PersistenceContext
      public void setEntityManager(EntityManager entityManager) {
          this.entityManager = entityManager;
      }
  
      /**
       * Workarround for a rapid migration from RowSet
       *
       * @param query
       * @return
       * @deprecated
       */
      @Deprecated
      public List<Object[]> findByNativeQuery(String query) {
          return createNativeQuery(query).getResultList();
      }
  
      @SuppressWarnings(value = "unchecked")
      protected List<E> find(String query) {
          return entityManager.createQuery(query).getResultList();
      }
  
     @SuppressWarnings(value = "unchecked")
     protected List<E> findByNamedQuery(String query) {
         return entityManager.createNamedQuery(query).getResultList();
     }
 }