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.BasicRowProcessor;
023import org.apache.commons.dbutils.ResultSetHandler;
024import org.apache.commons.dbutils.RowProcessor;
025
026/**
027 * <code>ResultSetHandler</code> implementation that converts a
028 * <code>ResultSet</code> into an <code>Object[]</code>. This class is
029 * thread safe.
030 *
031 * @see org.apache.commons.dbutils.ResultSetHandler
032 */
033public class ArrayHandler implements ResultSetHandler<Object[]> {
034
035    /**
036     * Singleton processor instance that handlers share to save memory.  Notice
037     * the default scoping to allow only classes in this package to use this
038     * instance.
039     */
040    static final RowProcessor ROW_PROCESSOR = new BasicRowProcessor();
041
042    /**
043     * The RowProcessor implementation to use when converting rows
044     * into arrays.
045     */
046    private final RowProcessor convert;
047
048    /**
049     * Creates a new instance of ArrayHandler using a
050     * <code>BasicRowProcessor</code> for conversion.
051     */
052    public ArrayHandler() {
053        this(ROW_PROCESSOR);
054    }
055
056    /**
057     * Creates a new instance of ArrayHandler.
058     *
059     * @param convert The <code>RowProcessor</code> implementation
060     * to use when converting rows into arrays.
061     */
062    public ArrayHandler(RowProcessor convert) {
063        super();
064        this.convert = convert;
065    }
066
067    /**
068     * Places the column values from the first row in an <code>Object[]</code>.
069     * @param rs <code>ResultSet</code> to process.
070     * @return An Object[] or <code>null</code> if there are no rows in the
071     * <code>ResultSet</code>.
072     *
073     * @throws SQLException if a database access error occurs
074     * @see org.apache.commons.dbutils.ResultSetHandler#handle(java.sql.ResultSet)
075     */
076    @Override
077    public Object[] handle(ResultSet rs) throws SQLException {
078        return rs.next() ? this.convert.toArray(rs) : null;
079    }
080
081}