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1   /***************************************************************************************
2    * Copyright (c) Jonas Bonér, Alexandre Vasseur. All rights reserved.                 *
3    * http://aspectwerkz.codehaus.org                                                    *
4    * ---------------------------------------------------------------------------------- *
5    * The software in this package is published under the terms of the LGPL license      *
6    * a copy of which has been included with this distribution in the license.txt file.  *
7    **************************************************************************************/
8   package org.codehaus.aspectwerkz;
9   
10  import java.io.InputStream;
11  import java.net.URL;
12  
13  /***
14   * Utility methods dealing with the context class loader. Fail-over is provided to the default class loader.
15   * 
16   * @author <a href="mailto:jboner@codehaus.org">Jonas Bonér </a>
17   */
18  public final class ContextClassLoader {
19      /***
20       * Loads a class from the context class loader or, if that fails, from the default class loader.
21       * 
22       * @param name is the name of the class to load.
23       * @return a <code>Class</code> object.
24       * @throws ClassNotFoundException if the class was not found.
25       */
26      public static Class loadClass(final String name) throws ClassNotFoundException {
27          Class cls = null;
28          try {
29              cls = Thread.currentThread().getContextClassLoader().loadClass(name);
30          } catch (Exception e) {
31              cls = Class.forName(name);
32          }
33          return cls;
34      }
35  
36      /***
37       * Loads a resource from the context class loader or, if that fails, from the default class loader.
38       * 
39       * @param name is the name of the resource to load.
40       * @return a <code>URL</code> object.
41       */
42      public static URL loadResource(final String name) {
43          try {
44              return Thread.currentThread().getContextClassLoader().getResource(name);
45          } catch (Exception e) {
46              return ClassLoader.class.getClassLoader().getResource(name);
47          }
48      }
49  
50      /***
51       * Loads a resource from the context class loader or, if that fails, from the default class loader, as stream
52       * 
53       * @param name is the name of the resource to load.
54       * @return a <code>InputStream</code> object.
55       */
56      public static InputStream getResourceAsStream(final String name) {
57          InputStream stream = null;
58          ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader();
59          if (contextClassLoader != null) {
60              stream = contextClassLoader.getResourceAsStream(name);
61          }
62          if (stream == null) {
63              ClassLoader classLoader = ClassLoader.class.getClassLoader();
64              if (classLoader != null) {
65                  stream = classLoader.getResourceAsStream(name);
66              }
67          }
68          return stream;
69      }
70  
71      /***
72       * Returns the context class loader.
73       * 
74       * @return the context class loader
75       */
76      public static ClassLoader getLoader() {
77          ClassLoader loader = Thread.currentThread().getContextClassLoader();
78          if (loader == null) {
79              loader = ClassLoader.class.getClassLoader();
80          }
81          return loader;
82      }
83  }