EmptyStringUserType.java

/*
 * This program is free software; you can redistribute it and/or modify it under the 
 * terms of the GNU General Public License, version 2 as published by the Free Software 
 * Foundation.
 *
 * You should have received a copy of the GNU General Public License along with this 
 * program; if not, you can obtain a copy at http://www.gnu.org/licenses/gpl-2.0.html 
 * or from the Free Software Foundation, Inc., 
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * This program 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 General Public License for more details.
 *
 * 
 * Copyright 2005-2008 Pentaho Corporation.  All rights reserved. 
 * 
 * @created Jun 20, 2005 
 * @author Marc Batchelor
 * 
 */

package org.pentaho.platform.repository.hibernate.usertypes;

import java.io.Serializable;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Types;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.hibernate.Hibernate;
import org.hibernate.HibernateException;
import org.hibernate.usertype.UserType;
import org.hibernate.util.EqualsHelper;
import org.pentaho.platform.engine.core.system.PentahoSystem;
import org.pentaho.platform.repository.messages.Messages;

public class EmptyStringUserType implements UserType {
  private static final Log log = LogFactory.getLog(EmptyStringUserType.class);

  private final static boolean debug = PentahoSystem.debug;

  private static final String PENTAHOEMPTY = Messages.getInstance().getString("EMPTYSTRTYPE.CODE_PENTAHO_EMPTY_STRING"); //$NON-NLS-1$

  private static final int[] SQLTYPE = { Types.VARCHAR };

  /*
   * (non-Javadoc)
   * 
   * @see org.hibernate.usertype.UserType#sqlTypes()
   */
  public int[] sqlTypes() {
    return EmptyStringUserType.SQLTYPE;
  }

  /*
   * (non-Javadoc)
   * 
   * @see org.hibernate.usertype.UserType#returnedClass()
   */
  public Class returnedClass() {
    return String.class;
  }

  /*
   * (non-Javadoc)
   * 
   * @see org.hibernate.usertype.UserType#equals(java.lang.Object,
   *      java.lang.Object)
   */
  public boolean equals(final Object arg0, final Object arg1) throws HibernateException {
    return EqualsHelper.equals(arg0, arg1);
  }

  /*
   * (non-Javadoc)
   * 
   * @see org.hibernate.usertype.UserType#hashCode(java.lang.Object)
   */
  public int hashCode(final Object arg0) throws HibernateException {
    return arg0.hashCode();
  }

  /*
   * (non-Javadoc)
   * 
   * @see org.hibernate.usertype.UserType#nullSafeGet(java.sql.ResultSet,
   *      java.lang.String[], java.lang.Object)
   */
  public Object nullSafeGet(final ResultSet arg0, final String[] arg1, final Object arg2) throws HibernateException,
      SQLException {
    if (EmptyStringUserType.debug) {
      EmptyStringUserType.log.debug(Messages.getInstance().getString("EMPTYSTRTYPE.DEBUG_NULL_SAFE_GET")); //$NON-NLS-1$
    }
    String colValue = (String) Hibernate.STRING.nullSafeGet(arg0, arg1[0]);
    // _PENTAHOEMPTY_ shouldn't appear in the wild. So, check the string in
    // the DB for this flag,
    // and if it's there, then this must be an empty string.
    return ((colValue != null) ? (colValue.equals(EmptyStringUserType.PENTAHOEMPTY) ? "" : colValue) : null); //$NON-NLS-1$
  }

  /*
   * (non-Javadoc)
   * 
   * @see org.hibernate.usertype.UserType#nullSafeSet(java.sql.PreparedStatement,
   *      java.lang.Object, int)
   */
  public void nullSafeSet(final PreparedStatement arg0, final Object arg1, final int arg2) throws HibernateException,
      SQLException {
    // If this is an empty string, write _PENTAHOEMPTY_ into the database.
    if (EmptyStringUserType.debug) {
      EmptyStringUserType.log.debug(Messages.getInstance().getString("EMPTYSTRTYPE.DEBUG_NULL_SAFE_SET")); //$NON-NLS-1$
    }
    Hibernate.STRING.nullSafeSet(arg0, (arg1 != null) ? ((((String) arg1).length() > 0) ? arg1
        : EmptyStringUserType.PENTAHOEMPTY) : arg1, arg2);
  }

  /*
   * (non-Javadoc)
   * 
   * @see org.hibernate.usertype.UserType#deepCopy(java.lang.Object)
   */
  public Object deepCopy(final Object arg0) throws HibernateException {
    return arg0;
  }

  /*
   * (non-Javadoc)
   * 
   * @see org.hibernate.usertype.UserType#isMutable()
   */
  public boolean isMutable() {
    return false;
  }

  /*
   * (non-Javadoc)
   * 
   * @see org.hibernate.usertype.UserType#disassemble(java.lang.Object)
   */
  public Serializable disassemble(final Object arg0) throws HibernateException {
    return (Serializable) arg0;
  }

  /*
   * (non-Javadoc)
   * 
   * @see org.hibernate.usertype.UserType#assemble(java.io.Serializable,
   *      java.lang.Object)
   */
  public Object assemble(final Serializable arg0, final Object arg1) throws HibernateException {
    return arg0;
  }

  /*
   * (non-Javadoc)
   * 
   * @see org.hibernate.usertype.UserType#replace(java.lang.Object,
   *      java.lang.Object, java.lang.Object)
   */
  public Object replace(final Object arg0, final Object arg1, final Object arg2) throws HibernateException {
    return arg0;
  }

}