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} implementation that converts the first
27 * {@code ResultSet} row into a JavaBean. This class is thread safe.
28 *
29 * @param <T> the target bean type
30 * @see org.apache.commons.dbutils.ResultSetHandler
31 */
32 public class BeanHandler<T> implements ResultSetHandler<T> {
33
34 /**
35 * The Class of beans produced by this handler.
36 */
37 private final Class<? extends T> type;
38
39 /**
40 * The RowProcessor implementation to use when converting rows
41 * into beans.
42 */
43 private final RowProcessor convert;
44
45 /**
46 * Creates a new instance of BeanHandler.
47 *
48 * @param type The Class that objects returned from {@code handle()}
49 * are created from.
50 */
51 public BeanHandler(final Class<? extends T> type) {
52 this(type, ArrayHandler.ROW_PROCESSOR);
53 }
54
55 /**
56 * Creates a new instance of BeanHandler.
57 *
58 * @param type The Class that objects returned from {@code handle()}
59 * are created from.
60 * @param convert The {@code RowProcessor} implementation
61 * to use when converting rows into beans.
62 */
63 public BeanHandler(final Class<? extends T> type, final RowProcessor convert) {
64 this.type = type;
65 this.convert = convert;
66 }
67
68 /**
69 * Convert the first row of the {@code ResultSet} into a bean with the
70 * {@code Class} given in the constructor.
71 * @param resultSet {@code ResultSet} to process.
72 * @return An initialized JavaBean or {@code null} if there were no
73 * rows in the {@code ResultSet}.
74 *
75 * @throws SQLException if a database access error occurs
76 * @see org.apache.commons.dbutils.ResultSetHandler#handle(java.sql.ResultSet)
77 */
78 @Override
79 public T handle(final ResultSet resultSet) throws SQLException {
80 return resultSet.next() ? this.convert.toBean(resultSet, this.type) : null;
81 }
82
83 }