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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 JavaBean. This class is thread safe.
28   * 
29   * @see org.apache.commons.dbutils.ResultSetHandler
30   */
31  public class BeanHandler implements ResultSetHandler {
32  
33      /**
34       * The Class of beans produced by this handler.
35       */
36      private Class type = null;
37  
38      /**
39       * The RowProcessor implementation to use when converting rows 
40       * into beans.
41       */
42      private RowProcessor convert = ArrayHandler.ROW_PROCESSOR;
43  
44      /** 
45       * Creates a new instance of BeanHandler.
46       * 
47       * @param type The Class that objects returned from <code>handle()</code>
48       * are created from.
49       */
50      public BeanHandler(Class type) {
51          this.type = type;
52      }
53  
54      /** 
55       * Creates a new instance of BeanHandler.
56       * 
57       * @param type The Class that objects returned from <code>handle()</code>
58       * are created from.
59       * @param convert The <code>RowProcessor</code> implementation 
60       * to use when converting rows into beans.
61       */
62      public BeanHandler(Class type, RowProcessor convert) {
63          this.type = type;
64          this.convert = convert;
65      }
66  
67      /**
68       * Convert the first row of the <code>ResultSet</code> into a bean with the
69       * <code>Class</code> given in the constructor.
70       * 
71       * @return An initialized JavaBean or <code>null</code> if there were no 
72       * rows in the <code>ResultSet</code>.
73       * 
74       * @throws SQLException if a database access error occurs
75       * @see org.apache.commons.dbutils.ResultSetHandler#handle(java.sql.ResultSet)
76       */
77      public Object handle(ResultSet rs) throws SQLException {
78          return rs.next() ? this.convert.toBean(rs, this.type) : null;
79      }
80  
81  }