LongStringUserType.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
 * 
 */

/*
 * This class is built to support saving and loading of long strings from hibernate. Specifically,
 * strings greater than 254 characters will be saved as CLOBs instead of varchars. The 254 character
 * limit was specifically chosen as the limit because MySQL has a 255 character limit on the length
 * of a varchar.
 * 
 * This implementation will return the CLOBs as StringBuffers.
 */
package org.pentaho.platform.repository.hibernate.usertypes;

import java.io.Serializable;
import java.io.StringReader;
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.HibernateException;
import org.hibernate.usertype.UserType;
import org.pentaho.platform.engine.core.system.PentahoSystem;
import org.pentaho.platform.repository.messages.Messages;

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

  private final static boolean debug = PentahoSystem.debug;

  private static final int[] SQLTYPE = { Types.CLOB }; // Persists as CLOBs

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

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

  /*
   * (non-Javadoc)
   * 
   * @see org.hibernate.usertype.UserType#equals(java.lang.Object,
   *      java.lang.Object)
   */
  public boolean equals(final Object x, final Object y) throws HibernateException {
    if (x == y) {
      return true;
    }
    if ((x == null) || (y == null) || (!(x instanceof StringBuffer)) || (!(y instanceof StringBuffer))) {
      return false;
    }
    return x.toString().equals(y.toString());
  }

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

  /*
   * (non-Javadoc)
   * 
   * @see org.hibernate.usertype.UserType#nullSafeGet(java.sql.ResultSet,
   *      java.lang.String[], java.lang.Object)
   */
  public Object nullSafeGet(final ResultSet rs, final String[] names, final Object owner) throws HibernateException,
      SQLException {
    if (LongStringUserType.debug) {
      LongStringUserType.log.debug(Messages.getInstance().getString("LONGSTRTYPE.DEBUG_NULL_SAFE_GET")); //$NON-NLS-1$
    }
    String longStr = rs.getString(names[0]);
    return (longStr != null) ? new StringBuffer(longStr) : null;
  }

  /*
   * (non-Javadoc)
   * 
   * @see org.hibernate.usertype.UserType#nullSafeSet(java.sql.PreparedStatement,
   *      java.lang.Object, int)
   */
  public void nullSafeSet(final PreparedStatement st, final Object value, final int index) throws HibernateException,
      SQLException {
    if (LongStringUserType.debug) {
      LongStringUserType.log.debug(Messages.getInstance().getString("LONGSTRTYPE.DEBUG_NULL_SAFE_SET")); //$NON-NLS-1$
    }
    if (value != null) {
      StringReader rdr = new StringReader(value.toString());
      int sLen = ((StringBuffer) value).length();
      st.setCharacterStream(index, rdr, sLen);
    } else {
      st.setNull(index, LongStringUserType.SQLTYPE[0]);
    }
  }

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

  /*
   * (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 value) throws HibernateException {
    return (Serializable) value;
  }

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

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