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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *      http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  package org.apache.commons.dbutils.handlers;
18  
19  import java.sql.ResultSet;
20  import java.sql.SQLException;
21  
22  import org.apache.commons.dbutils.ResultSetHandler;
23  import org.apache.commons.dbutils.RowProcessor;
24  
25  /**
26   * <code>ResultSetHandler</code> implementation that converts the first
27   * <code>ResultSet</code> row into a <code>Map</code>. This class is thread 
28   * safe.
29   * 
30   * @see org.apache.commons.dbutils.ResultSetHandler
31   */
32  public class MapHandler implements ResultSetHandler {
33  
34      /**
35       * The RowProcessor implementation to use when converting rows 
36       * into Maps.
37       */
38      private RowProcessor convert = ArrayHandler.ROW_PROCESSOR;
39  
40      /** 
41       * Creates a new instance of MapHandler using a 
42       * <code>BasicRowProcessor</code> for conversion.
43       */
44      public MapHandler() {
45          super();
46      }
47  
48      /** 
49       * Creates a new instance of MapHandler.
50       * 
51       * @param convert The <code>RowProcessor</code> implementation 
52       * to use when converting rows into Maps.
53       */
54      public MapHandler(RowProcessor convert) {
55          super();
56          this.convert = convert;
57      }
58  
59      /**
60       * Converts the first row in the <code>ResultSet</code> into a 
61       * <code>Map</code>.
62       * 
63       * @return A <code>Map</code> with the values from the first row or 
64       * <code>null</code> if there are no rows in the <code>ResultSet</code>. 
65       * 
66       * @throws SQLException if a database access error occurs
67       * 
68       * @see org.apache.commons.dbutils.ResultSetHandler#handle(java.sql.ResultSet)
69       */
70      public Object handle(ResultSet rs) throws SQLException {
71          return rs.next() ? this.convert.toMap(rs) : null;
72      }
73  
74  }