/* 
 * $Header: /home/cvs/commons/dbutils-1.0/ja/src/org/apache/commons/dbutils/handlers/BeanHandler.java,v 1.1.1.1 2004/02/13 10:02:04 hioki Exp $
 * $Revision: 1.1.1.1 $
 * $Date: 2004/02/13 10:02:04 $
 * 
 * ====================================================================
 * 
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2003 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. 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.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowledgement:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgement may appear in the software itself,
 *    if and wherever such third-party acknowledgements normally appear.
 *
 * 4. The names "The Jakarta Project", "Commons", and "Apache Software
 *    Foundation" must not be used to endorse or promote products derived
 *    from this software without prior written permission. For written
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache"
 *    nor may "Apache" appear in their names without prior written
 *    permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 APACHE SOFTWARE FOUNDATION OR
 * ITS 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.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */

package org.apache.commons.dbutils.handlers;

import java.sql.ResultSet;
import java.sql.SQLException;

import org.apache.commons.dbutils.BasicRowProcessor;
import org.apache.commons.dbutils.ResultSetHandler;
import org.apache.commons.dbutils.RowProcessor;

/**
 * <code>ResultSet</code> の先頭行を JavaBean へ変換する <code>ResultSetHandler</code> の実装です。 
 * このクラスはスレッドセーフです。 
 * {@primary <code>ResultSetHandler</code> implementation that converts the first 
 * <code>ResultSet</code> row into a JavaBean. This class is thread safe.}
 * 
 * @see ResultSetHandler
 * 
 * @author Juozas Baliuka
 * @author David Graham
 * @translator 小川 環
 * @editor 日置 聡
 * @status underproof
 * @update 2003/12/22
 */
public class BeanHandler implements ResultSetHandler {

    /**
     * The Class of beans produced by this handler.
     */
    private Class type = null;

    /**
     * The RowProcessor implementation to use when converting rows 
     * into beans.
     */
    private RowProcessor convert = BasicRowProcessor.instance();

    /** 
     * BeanHandler の新規インスタンスを作成します。 
     * {@primary Creates a new instance of BeanHandler.}
     * 
     * @param type <code>handle()</code> より返されたオブジェクトを作るためのクラス。
     * {@primary The Class that objects returned from <code>handle()</code>
     * are created from.}
     */
    public BeanHandler(Class type) {
        this.type = type;
    }

    /** 
     * BeanHandler の新規インスタンスを作成します。 
     * {@primary Creates a new instance of BeanHandler.}
     * 
     * @param type <code>handle()</code> より返されたオブジェクトを作るためのクラス。
     * {@primary The Class that objects returned from <code>handle()</code>
     * are created from.}
     * @param convert 行を配列へ変換する際に使用する <code>RowProcessor</code> 実装。
     * {@primary The <code>RowProcessor</code> implementation 
     * to use when converting rows into beans.}
     */
    public BeanHandler(Class type, RowProcessor convert) {
        this.type = type;
        this.convert = convert;
    }

    /**
     * <code>ResultSet</code> の先頭行をコンストラクタに渡された <code>Class</code> に基づいた Bean へ変換します。
     * {@primary Convert the first row of the <code>ResultSet</code> into a bean with the
     * <code>Class</code> given in the constructor.}
     * 
     * @return 初期化されたJavaBean、<code>ResultSet</code> が０行の場合は <code>null</code>。
     * {@primary An initialized JavaBean or <code>null</code> if there were no 
     * rows in the <code>ResultSet</code>.}
     * 
     * @throws SQLException
     * @see org.apache.commons.dbutils.ResultSetHandler#handle(java.sql.ResultSet)
     */
    public Object handle(ResultSet rs) throws SQLException {
        return rs.next() ? this.convert.toBean(rs, this.type) : null;
    }

}