1 /*
2 * Copyright 2008-2013 smartics, Kronseder & Reiner GmbH
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16 package de.smartics.util.test.lang;
17
18 import static org.junit.Assert.assertNotNull;
19 import static org.junit.Assert.fail;
20
21 import java.lang.reflect.Constructor;
22 import java.lang.reflect.InvocationTargetException;
23
24 import org.apache.commons.lang.ArrayUtils;
25
26 /**
27 * Provides utility functions on the language level.
28 *
29 * @author <a href="mailto:robert.reiner@smartics.de">Robert Reiner</a>
30 * @version $Revision:591 $
31 */
32 public final class LangTestUtils
33 {
34 // ********************************* Fields *********************************
35
36 // --- constants ------------------------------------------------------------
37
38 // --- members --------------------------------------------------------------
39
40 // ****************************** Initializer *******************************
41
42 // ****************************** Constructors ******************************
43
44 /**
45 * Utility class pattern.
46 */
47 private LangTestUtils()
48 {
49 }
50
51 // ****************************** Inner Classes *****************************
52
53 // ********************************* Methods ********************************
54
55 // --- init -----------------------------------------------------------------
56
57 // --- get&set --------------------------------------------------------------
58
59 // --- business -------------------------------------------------------------
60
61 /* CHECKSTYLE:OFF */
62 /**
63 * Creates an instance of the private no-args constructor.
64 * <p>
65 * This is a kind of dysfunction to get rid of missing test coverage for
66 * private constructors of constant or utility classes. To keep the overhead
67 * for this dysfuntion small, this method is provided.
68 * </p>
69 *
70 * @param clazz the class to instantiate with the private no-args constructor.
71 * @return the instance of the class.
72 * @throws NoSuchMethodException if there is no private no-args constructor.
73 * @throws SecurityException if the request to make the private constructor
74 * accessible is denied.
75 * @throws InstantiationException if the class that declares the underlying
76 * constructor represents an abstract class.
77 * @throws InvocationTargetException if the underlying constructor throws an
78 * exception.
79 * @throws ExceptionInInitializerError if the initialization provoked by this
80 * method fails.
81 * @throws IllegalStateException if something strange happens that we did not
82 * take into account.
83 * @see #runPrivateConstructorTest(Class)
84 */
85 public static Object createInstanceForPrivateNoArgsConstructor(
86 final Class<?> clazz) throws SecurityException, NoSuchMethodException,
87 InstantiationException, InvocationTargetException,
88 ExceptionInInitializerError, IllegalStateException
89 /* CHECKSTYLE:ON */
90 {
91 final Constructor<?> constructor =
92 clazz.getDeclaredConstructor(ArrayUtils.EMPTY_CLASS_ARRAY);
93 constructor.setAccessible(true);
94 try
95 {
96 final Object instance =
97 constructor.newInstance(ArrayUtils.EMPTY_OBJECT_ARRAY);
98 return instance;
99 }
100 catch (final IllegalAccessException e)
101 {
102 throw new IllegalStateException(
103 "Caught an exception that should never been raised."
104 + " We set the constructor to be accessible, but the exception"
105 + " informs us that it is not. Strange...", e);
106 }
107 catch (final IllegalArgumentException e)
108 {
109 throw new IllegalStateException(
110 "Caught an exception that should never been raised."
111 + " We have not parameters to set, but get an illegal"
112 + " argument exception. Strange...", e);
113 }
114 }
115
116 /**
117 * Tests creating an instance for a private constructor.
118 * <p>
119 * This is a kind of dysfunction to get rid of missing test coverage for
120 * private constructors of constant or utility classes. To keep the overhead
121 * for this dysfuntion small, this method is provided.
122 * </p>
123 * {@example "Example Usage" public void testPrivateConstructor()
124 * LangTestUtils.runPrivateConstructorTest(FileNameUtils.class); }
125 *
126 * @param clazz the class to instantiate with the private no-args constructor.
127 * @see #createInstanceForPrivateNoArgsConstructor(Class)
128 */
129 public static void runPrivateConstructorTest(final Class<?> clazz)
130 {
131 try
132 {
133 final Object instance = createInstanceForPrivateNoArgsConstructor(clazz);
134 assertNotNull("Constructor should create an instance.", instance);
135 }
136 catch (final Exception e)
137 {
138 fail("Unexpected exception raised: " + e.getMessage());
139 }
140 }
141
142 /**
143 * Removes all whitespaces from the input string.
144 *
145 * @param input the input string to remove all whitespaces.
146 * @return the input stream without whitespaces or <code>null</code> if the
147 * input string is <code>null</code>.
148 */
149 public static String removeAllWhitespaces(final String input)
150 {
151 if (input != null)
152 {
153 return input.replaceAll("\\s+", "");
154 }
155 return null;
156 }
157
158 // --- object basics --------------------------------------------------------
159
160 }