    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one or more
    003 * contributor license agreements.  See the NOTICE file distributed with
    004 * this work for additional information regarding copyright ownership.
    005 * The ASF licenses this file to You under the Apache License, Version 2.0
    006 * (the "License"); you may not use this file except in compliance with
    007 * the License.  You may obtain a copy of the License at
    008 *
    009 *      http://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 * Unless required by applicable law or agreed to in writing, software
    012 * distributed under the License is distributed on an "AS IS" BASIS,
    013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 * See the License for the specific language governing permissions and
    015 * limitations under the License.
    016 */
    017package org.apache.commons.dbutils.handlers;
    018
    019import java.sql.ResultSet;
    020import java.sql.SQLException;
    021
    022import org.apache.commons.dbutils.ResultSetHandler;
    023import org.apache.commons.dbutils.RowProcessor;
    024
    025/**
    026 * {@code ResultSetHandler} implementation that converts the first
    027 * {@code ResultSet} row into a JavaBean. This class is thread safe.
    028 *
    029 * @param <T> the target bean type
    030 * @see org.apache.commons.dbutils.ResultSetHandler
    031 */
    032public class BeanHandler<T> implements ResultSetHandler<T> {
    033
    034    /**
    035     * The Class of beans produced by this handler.
    036     */
    037    private final Class<? extends T> type;
    038
    039    /**
    040     * The RowProcessor implementation to use when converting rows
    041     * into beans.
    042     */
    043    private final RowProcessor convert;
    044
    045    /**
    046     * Creates a new instance of BeanHandler.
    047     *
    048     * @param type The Class that objects returned from {@code handle()}
    049     * are created from.
    050     */
    051    public BeanHandler(final Class<? extends T> type) {
    052        this(type, ArrayHandler.ROW_PROCESSOR);
    053    }
    054
    055    /**
    056     * Creates a new instance of BeanHandler.
    057     *
    058     * @param type The Class that objects returned from {@code handle()}
    059     * are created from.
    060     * @param convert The {@code RowProcessor} implementation
    061     * to use when converting rows into beans.
    062     */
    063    public BeanHandler(final Class<? extends T> type, final RowProcessor convert) {
    064        this.type = type;
    065        this.convert = convert;
    066    }
    067
    068    /**
    069     * Convert the first row of the {@code ResultSet} into a bean with the
    070     * {@code Class} given in the constructor.
    071     * @param resultSet {@code ResultSet} to process.
    072     * @return An initialized JavaBean or {@code null} if there were no
    073     * rows in the {@code ResultSet}.
    074     *
    075     * @throws SQLException if a database access error occurs
    076     * @see org.apache.commons.dbutils.ResultSetHandler#handle(java.sql.ResultSet)
    077     */
    078    @Override
    079    public T handle(final ResultSet resultSet) throws SQLException {
    080        return resultSet.next() ? this.convert.toBean(resultSet, this.type) : null;
    081    }
    082
    083}