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     */
017    package org.apache.commons.dbutils.handlers;
018    
019    import java.sql.ResultSet;
020    import java.sql.SQLException;
021    import java.util.Map;
022    
023    import org.apache.commons.dbutils.ResultSetHandler;
024    import org.apache.commons.dbutils.RowProcessor;
025    
026    /**
027     * <code>ResultSetHandler</code> implementation that converts the first
028     * <code>ResultSet</code> row into a <code>Map</code>. This class is thread
029     * safe.
030     *
031     * @see org.apache.commons.dbutils.ResultSetHandler
032     */
033    public class MapHandler implements ResultSetHandler<Map<String, Object>> {
034    
035        /**
036         * The RowProcessor implementation to use when converting rows
037         * into Maps.
038         */
039        private final RowProcessor convert;
040    
041        /**
042         * Creates a new instance of MapHandler using a
043         * <code>BasicRowProcessor</code> for conversion.
044         */
045        public MapHandler() {
046            this(ArrayHandler.ROW_PROCESSOR);
047        }
048    
049        /**
050         * Creates a new instance of MapHandler.
051         *
052         * @param convert The <code>RowProcessor</code> implementation
053         * to use when converting rows into Maps.
054         */
055        public MapHandler(RowProcessor convert) {
056            super();
057            this.convert = convert;
058        }
059    
060        /**
061         * Converts the first row in the <code>ResultSet</code> into a
062         * <code>Map</code>.
063         * @param rs <code>ResultSet</code> to process.
064         * @return A <code>Map</code> with the values from the first row or
065         * <code>null</code> if there are no rows in the <code>ResultSet</code>.
066         *
067         * @throws SQLException if a database access error occurs
068         *
069         * @see org.apache.commons.dbutils.ResultSetHandler#handle(java.sql.ResultSet)
070         */
071        public Map<String, Object> handle(ResultSet rs) throws SQLException {
072            return rs.next() ? this.convert.toMap(rs) : null;
073        }
074    
075    }