1 /*
2 * $Id: Config.java,v 1.2 2011/01/02 15:04:11 oboehm Exp $
3 *
4 * Copyright (c) 2008 by Oliver Boehm
5 *
6 * Licensed under the Apache License, Version 2.0 (the "License");
7 * you may not use this file except in compliance with the License.
8 * You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing, software
13 * distributed under the License is distributed on an "AS IS" BASIS,
14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express orimplied.
15 * See the License for the specific language governing permissions and
16 * limitations under the License.
17 *
18 * (c)reated 22.10.2008 by oliver (ob@oasd.de)
19 */
20 package patterntesting.sample;
21
22 import java.io.*;
23 import java.util.Properties;
24
25 import org.apache.commons.logging.Log;
26 import org.apache.commons.logging.impl.LogFactoryImpl;
27
28 import patterntesting.annotation.check.runtime.*;
29 import patterntesting.runtime.NullConstants;
30
31 /**
32 * This class is an example how NullPointerExceptions may happen.
33 *
34 * @author <a href="boehm@javatux.de">oliver</a>
35 * @since 22.10.2008
36 * @version $Revision: 1.2 $
37 */
38 public class Config {
39
40 private static final Log log = LogFactoryImpl.getLog(Config.class);
41 private static String propertyResource = "default.properties";
42 private static Properties properties = null;
43
44 /** Utility class - no need to instantiate it. */
45 private Config() {}
46
47 /**
48 * Sets the resource.
49 *
50 * @param name the new resource
51 */
52 public static void setResource(final String name) {
53 propertyResource = name;
54 properties = null;
55 }
56
57 /**
58 * Gets the resource.
59 *
60 * @return the resource
61 */
62 public static String getResource() {
63 return propertyResource;
64 }
65
66 /**
67 * Gets the version.
68 *
69 * @return the version
70 */
71 public static String getVersion() {
72 return getProperty("patterntesting.sample.version");
73 }
74
75 /**
76 * This is an example how to use NULL_OBJECT as argument. If you don't want to
77 * set a prefix or suffix use NullConstants.NULL_OBJECT as argument. <br/>
78 * BTW: The code would also work if you would use NullConstants.NULL_STRING as
79 * arguemnt (because it is an empty string).
80 *
81 * @param prefix e.g. "v" or NullConstants.NULL_OBJECT if you don't want to set a
82 * prefix
83 * @param version e.g. "0.9.7"
84 * @param suffix e.g. "-SNAPSHOT" or NullConstants.NULL_OBJECT if you don't want to set
85 * a suffix
86 *
87 * @since 13-Jun-2009
88 * @author oliver
89 */
90 public static void setVersion(final Object prefix, String version,
91 final Object suffix) {
92 if (prefix != NullConstants.NULL_OBJECT) {
93 version = prefix.toString() + version;
94 }
95 if (suffix != NullConstants.NULL_OBJECT) {
96 version = version + suffix.toString();
97 }
98 setProperty("patterntesting.sample.version", version);
99 }
100
101 /**
102 * This is an example for a method which may return null.
103 *
104 * @param name of the key
105 *
106 * @return value of the property
107 */
108 @MayReturnNull
109 public static String getProperty(final String name) {
110 Properties props = getProperties();
111 return props.getProperty(name);
112 }
113
114 /**
115 * This is a (bad) example how you can use @NullArgsAllowed and combine it
116 * with @NotNull.
117 * <br/>
118 * Don't use such kind of code in your project. A better approach would be
119 * to divide this methods into:
120 * <ul>
121 * <li>setProperty(String, String)</li>
122 * <li>resetProperty(String)
123 * </ul>
124 *
125 * @param key the key
126 * @param value the value
127 */
128 @NullArgsAllowed
129 public static void setProperty(@NotNull final String key, final String value) {
130 Properties properties = getProperties();
131 if (value == null) {
132 properties.remove(key);
133 } else {
134 properties.setProperty(key, value);
135 }
136 }
137
138 /**
139 * Gets the properties.
140 *
141 * @return the properties
142 */
143 public static synchronized Properties getProperties() {
144 if (properties != null) {
145 return properties;
146 }
147 properties = new Properties();
148 try {
149 properties.load(getPropertyStream());
150 log.info(propertyResource + " loaded");
151 return properties;
152 } catch (IOException ioe) {
153 log.warn("can't load properties", ioe);
154 return null;
155 }
156 }
157
158 /**
159 * Gets the property stream.
160 *
161 * @return the property stream
162 */
163 public static InputStream getPropertyStream() {
164 return Config.class.getResourceAsStream(propertyResource);
165 }
166
167 /**
168 * Gets the OS.
169 *
170 * @return the OS
171 */
172 public static String getOS() {
173 return System.getProperty("os.name");
174 }
175
176 /**
177 * Gets the JDK home.
178 *
179 * @return the JDK home
180 */
181 public static String getJdkHome() {
182 return System.getenv("JDK_HOME");
183 }
184
185 /**
186 * Gets the JDK home dir.
187 *
188 * @return the JDK home dir
189 */
190 public static File getJdkHomeDir() {
191 String jdkHome = getJdkHome();
192 assert jdkHome != null;
193 return new File(jdkHome);
194 }
195
196 }