/*
 * ContentTypeDAOImpl.java
 *
 * Created on March 5, 2005, 11:57 AM
 */

package desktopbeautifier.server.dao.impl;
import desktopbeautifier.server.hibernate.HibernateHelper;
import desktopbeautifier.server.domain.ContentType;
import desktopbeautifier.server.domain.ServerImage;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;
import org.hibernate.Query;
import org.hibernate.Session;

/**
 * ContentType data access object.
 *
 * @author Gili Tzabari
 */
public class ContentTypeDAOImpl
  implements desktopbeautifier.dao.ContentTypeDAO
{
  private static ContentTypeDAOImpl instance;
  private transient HibernateHelper hibernate = HibernateHelper.getInstance();
  
  
  /**
   * Creates a new ContentTypeDAOImpl.
   */
  private ContentTypeDAOImpl()
  {}
  
  /**
   * Returns the singleton instance.
   */
  public static ContentTypeDAOImpl getInstance()
  {
    if (instance==null)
      instance = new ContentTypeDAOImpl();
    return instance;
  }
  
  public void removeOrphans()
  {
    Session session = hibernate.getSession();
    Query getOrphans = session.createQuery("from " +
      ContentType.class.getName() +
      " type where type.id not in (select image.contentType from " +
      ServerImage.class.getName() + " image)");
    Iterator orphans = getOrphans.iterate();
    while (orphans.hasNext())
      session.delete(orphans.next());
  }
  
  public ContentType getContentType(String type, String subType)
  {
    Session session = hibernate.getSession();
    assert(session!=null): "Session may not be null";
    
    Query getCanonicalInstance = session.createQuery("from " +
      ContentType.class.getName() + " where type=:type and subType=:subType");
    getCanonicalInstance.setString("type", type);
    getCanonicalInstance.setString("subType", subType);
    getCanonicalInstance.setMaxResults(1);
    ContentType result = (ContentType) getCanonicalInstance.uniqueResult();
    if (result!=null)
      return result;
    else
      return null;
  }
  
  public ContentType getContentType(String value)
  {
    ContentType temp = new ContentType();
    temp.setValue(value);
    return getContentType(temp.getType(), temp.getSubType());
  }
  
  /**
   * Deletes the specified object.
   */
  public void delete(ContentType contentType)
  {
    Session session = hibernate.getSession();
    session.delete(contentType);
  }
  
  public ContentType save(ContentType contentType)
  {
    Session session = hibernate.getSession();
    ContentType result = (ContentType) session.merge(contentType);
    
    // Transfer associations to new instance
    for (ServerImage image: contentType.getImages())
      result.add(image);
    contentType.getImages().clear();
    return result;
  }
  
  /**
   * Returns all ContentTypes.
   */
  public Set<ContentType> list()
  {
    Session session = hibernate.getSession();
    Query getContentTypes = session.createQuery("from " +
      ContentType.class.getName());
    return new HashSet<ContentType>(getContentTypes.list());
  }
}