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.wrappers;
18
19 import java.lang.reflect.InvocationHandler;
20 import java.lang.reflect.Method;
21 import java.sql.ResultSet;
22
23 import org.apache.commons.dbutils.ProxyFactory;
24
25 /**
26 * Wraps a {@code ResultSet} to trim strings returned by the
27 * {@code getString()} and {@code getObject()} methods.
28 *
29 * <p>
30 * Usage Example:
31 * This example shows how to decorate ResultSets so processing continues as
32 * normal but all Strings are trimmed before being returned from the
33 * {@code ResultSet}.
34 * </p>
35 *
36 * <pre>
37 * ResultSet resultSet = // somehow get a ResultSet;
38 *
39 * // Substitute wrapped ResultSet with additional behavior for real ResultSet
40 * resultSet = StringTrimmedResultSet.wrap(resultSet);
41 *
42 * // Pass wrapped ResultSet to processor
43 * List list = new BasicRowProcessor().toBeanList(resultSet);
44 * </pre>
45 */
46 public class StringTrimmedResultSet implements InvocationHandler {
47
48 /**
49 * Wraps the {@code ResultSet} in an instance of this class. This is
50 * equivalent to:
51 * <pre>
52 * ProxyFactory.instance().createResultSet(new StringTrimmedResultSet(resultSet));
53 * </pre>
54 *
55 * @param resultSet The {@code ResultSet} to wrap.
56 * @return wrapped ResultSet
57 */
58 public static ResultSet wrap(final ResultSet resultSet) {
59 return ProxyFactory.instance().createResultSet(new StringTrimmedResultSet(resultSet));
60 }
61
62 /**
63 * The wrapped result.
64 */
65 private final ResultSet resultSet;
66
67 /**
68 * Constructs a new instance of {@code StringTrimmedResultSet}
69 * to wrap the specified {@code ResultSet}.
70 * @param resultSet ResultSet to wrap
71 */
72 public StringTrimmedResultSet(final ResultSet resultSet) {
73 this.resultSet = resultSet;
74 }
75
76 /**
77 * Intercept calls to the {@code getString()} and
78 * {@code getObject()} methods and trim any Strings before they're
79 * returned.
80 *
81 * @see java.lang.reflect.InvocationHandler#invoke(Object, java.lang.reflect.Method, Object[])
82 * @param proxy Not used; all method calls go to the internal result set
83 * @param method The method to invoke on the result set
84 * @param args The arguments to pass to the result set
85 * @return string trimmed result
86 * @throws Throwable error
87 */
88 @Override
89 public Object invoke(final Object proxy, final Method method, final Object[] args)
90 throws Throwable {
91
92 Object result = method.invoke(this.resultSet, args);
93
94 if (result instanceof String
95 && (method.getName().equals("getObject")
96 || method.getName().equals("getString"))) {
97 result = ((String) result).trim();
98 }
99
100 return result;
101 }
102
103 }