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.io;
17
18 import java.io.BufferedInputStream;
19 import java.io.InputStream;
20
21 /**
22 * Utilities to make unit tests with streams to resources from the class path
23 * easier.
24 *
25 * @author <a href="mailto:robert.reiner@smartics.de">Robert Reiner</a>
26 * @version $Revision:591 $
27 */
28 public final class IoTestUtils
29 {
30 // ********************************* Fields *********************************
31
32 // --- constants ------------------------------------------------------------
33
34 // --- members --------------------------------------------------------------
35
36 // ****************************** Initializer *******************************
37
38 // ****************************** Constructors ******************************
39
40 /**
41 * Utility class pattern.
42 */
43 private IoTestUtils()
44 {
45 }
46
47 // ****************************** Inner Classes *****************************
48
49 // ********************************* Methods ********************************
50
51 // --- init -----------------------------------------------------------------
52
53 // --- get&set --------------------------------------------------------------
54
55 // --- business -------------------------------------------------------------
56
57 /**
58 * Returns a stream to a resource on the class path loaded by the class loader
59 * of this class.
60 *
61 * @param resourceName name of the resource on the class path.
62 * @return the opened buffered stream. The client is responsible to close it.
63 * @throws IllegalArgumentException if {@code resourceName} cannot be found.
64 */
65 public static InputStream openStreamFromResource(final String resourceName)
66 throws IllegalArgumentException
67 {
68 final ClassLoader classLoader = IoTestUtils.class.getClassLoader(); // NOPMD
69 return openStreamFromResource(classLoader, resourceName);
70 }
71
72 /**
73 * Returns a stream to a resource on the class path loaded by the class loader
74 * that has loaded the given {@code type}.
75 *
76 * @param type the type to refer to the class loader to load the resource
77 * from. The resource is relative to this type.
78 * @param resourceName name of the resource on the class path.
79 * @return the opened buffered stream. The client is responsible to close it.
80 * @throws IllegalArgumentException if {@code resourceName} cannot be found.
81 */
82 public static InputStream openStreamFromResourceByTypeClassLoader(
83 final Class<?> type, final String resourceName)
84 throws IllegalArgumentException
85 {
86 try
87 {
88 return openStreamFromResource(type.getClassLoader(), resourceName);
89 }
90 catch (final IllegalArgumentException e)
91 {
92 throw new IllegalArgumentException(
93 "Cannot find resource '" // NOPMD
94 + resourceName
95 + "' on the class path using the class loader of type '"
96 + type.getClass().getName() + "'.", e);
97 }
98 }
99
100 /**
101 * Returns a stream to a resource on the class path.
102 *
103 * @param classLoader the class loader to load the resource from.
104 * @param resourceName name of the resource on the class path.
105 * @return the opened buffered stream. The client is responsible to close it.
106 * @throws IllegalArgumentException if {@code resourceName} cannot be found.
107 */
108 public static InputStream openStreamFromResource(
109 final ClassLoader classLoader, final String resourceName)
110 throws IllegalArgumentException
111 {
112 final InputStream input = classLoader.getResourceAsStream(resourceName);
113 if (input == null)
114 {
115 throw new IllegalArgumentException(
116 "Cannot find resource '" + resourceName
117 + "' on the class path using the given class loader.");
118 }
119
120 final BufferedInputStream bin = new BufferedInputStream(input);
121 return bin;
122 }
123
124 /**
125 * Returns the specified file from a resource relative to the given type.
126 *
127 * @param type the type to refer to the class loader to load the resource
128 * from. The resource is relative to this type.
129 * @param relativeResourceName name of the resource on the class path,
130 * relative to the passed in {@code type}.
131 * @return the opened buffered stream. The client is responsible to close it.
132 * @throws IllegalArgumentException if {@code relativeResourceName} cannot be
133 * found.
134 */
135 public static InputStream openStreamFromResource(final Class<?> type,
136 final String relativeResourceName) throws IllegalArgumentException
137 {
138 final InputStream input = type.getResourceAsStream(relativeResourceName);
139 if (input == null)
140 {
141 throw new IllegalArgumentException(
142 "Cannot find resource '" + relativeResourceName
143 + "' on the class path relative to type '"
144 + type.getClass().getName() + "'.");
145 }
146
147 final BufferedInputStream bin = new BufferedInputStream(input);
148 return bin;
149 }
150
151 // --- object basics --------------------------------------------------------
152
153 }