StringUserTypeBase.java

/*
 * $Id$
 *
 * Copyright 2006, The jCoderZ.org Project. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *    * Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
 *    * Redistributions in binary form must reproduce the above
 *      copyright notice, this list of conditions and the following
 *      disclaimer in the documentation and/or other materials
 *      provided with the distribution.
 *    * Neither the name of the jCoderZ.org Project nor the names of
 *      its contributors may be used to endorse or promote products
 *      derived from this software without specific prior written
 *      permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS AND CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.jcoderz.commons.util;

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

import org.hibernate.HibernateException;

/**
 *
 * This class is used by the Hibernate binding for RestrictedStrings.
 * A subclass has to implement the <code>fromString</code> method
 * for the particular RestrictedString. Be aware that VARCHAR is
 * restricted to 1000 Unicode characters!
 *
 * @author thomas.bodemer
 */
public abstract class StringUserTypeBase
    extends UserTypeBase
{
    private static final long serialVersionUID = 1L;
    private static final int SQL_TYPE = Types.VARCHAR;
    private static final int[] SQL_TYPES = {SQL_TYPE};

    /**
     * {@inheritDoc}
     */
    public Object nullSafeGet (ResultSet resultSet, String[] types,
        Object owner)
        throws HibernateException, SQLException
    {
        final String value = resultSet.getString(types[0]);
        final Object result;
        if (value == null || resultSet.wasNull())
        {
            result = null;
        }
        else if (value.length() == 0)
        {
            result = getEmptyOrNull();
        }
        else
        {
            result = fromString(value);
        }
        return result;
    }

    /**
     * Implement this method for the particular RestrictedString.
     *
     * @return either null or <code>fromString("")</code> if the
     *   StrongType permits this.
     */
    public abstract Object getEmptyOrNull ();

    /**
     * Implement this method for the particular RestrictedString.
     *
     * @param value the String representation of the mapped class
     * @return the instance of the mapped class
     */
    public abstract Object fromString (String value);

    /**
     * {@inheritDoc}
     */
    public void nullSafeSet (PreparedStatement statement, Object value,
        int index)
        throws HibernateException, SQLException
    {
        if (value != null)
        {
            statement.setString(index, value.toString());
        }
        else
        {
            statement.setNull(index, SQL_TYPE);
        }
    }

    /**
     * {@inheritDoc}
     */
    public int[] sqlTypes ()
    {
      return (int[]) SQL_TYPES.clone();
    }
}