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<T> implements ResultSetHandler<T> {
32
33 /**
34 * The Class of beans produced by this handler.
35 */
36 private final Class<T> type;
37
38 /**
39 * The RowProcessor implementation to use when converting rows
40 * into beans.
41 */
42 private final RowProcessor convert;
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<T> type) {
51 this(type, ArrayHandler.ROW_PROCESSOR);
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<T> 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 * @param rs <code>ResultSet</code> to process.
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 T handle(ResultSet rs) throws SQLException {
78 return rs.next() ? this.convert.toBean(rs, this.type) : null;
79 }
80
81 }