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</code> to trim strings returned by the
27 * <code>getString()</code> and <code>getObject()</code> 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</code>.
34 * </p>
35 *
36 * <pre>
37 * ResultSet rs = // somehow get a ResultSet;
38 *
39 * // Substitute wrapped ResultSet with additional behavior for real ResultSet
40 * rs = StringTrimmedResultSet.wrap(rs);
41 *
42 * // Pass wrapped ResultSet to processor
43 * List list = new BasicRowProcessor().toBeanList(rs);
44 * </pre>
45 */
46 public class StringTrimmedResultSet implements InvocationHandler {
47
48 /**
49 * The factory to create proxies with.
50 */
51 private static final ProxyFactory factory = ProxyFactory.instance();
52
53 /**
54 * Wraps the <code>ResultSet</code> in an instance of this class. This is
55 * equivalent to:
56 * <pre>
57 * ProxyFactory.instance().createResultSet(new StringTrimmedResultSet(rs));
58 * </pre>
59 *
60 * @param rs The <code>ResultSet</code> to wrap.
61 * @return wrapped ResultSet
62 */
63 public static ResultSet wrap(ResultSet rs) {
64 return factory.createResultSet(new StringTrimmedResultSet(rs));
65 }
66
67 /**
68 * The wrapped result.
69 */
70 private final ResultSet rs;
71
72 /**
73 * Constructs a new instance of <code>StringTrimmedResultSet</code>
74 * to wrap the specified <code>ResultSet</code>.
75 * @param rs ResultSet to wrap
76 */
77 public StringTrimmedResultSet(ResultSet rs) {
78 super();
79 this.rs = rs;
80 }
81
82 /**
83 * Intercept calls to the <code>getString()</code> and
84 * <code>getObject()</code> methods and trim any Strings before they're
85 * returned.
86 *
87 * @see java.lang.reflect.InvocationHandler#invoke(java.lang.Object, java.lang.reflect.Method, java.lang.Object[])
88 * @param proxy Not used; all method calls go to the internal result set
89 * @param method The method to invoke on the result set
90 * @param args The arguments to pass to the result set
91 * @return string trimmed result
92 * @throws Throwable error
93 */
94 public Object invoke(Object proxy, Method method, Object[] args)
95 throws Throwable {
96
97 Object result = method.invoke(this.rs, args);
98
99 if (method.getName().equals("getObject")
100 || method.getName().equals("getString")) {
101
102 if (result instanceof String) {
103 result = ((String) result).trim();
104 }
105 }
106
107 return result;
108 }
109
110 }