View Javadoc
1   package org.apache.maven.surefire.booter;
2   
3   /*
4    * Licensed to the Apache Software Foundation (ASF) under one
5    * or more contributor license agreements.  See the NOTICE file
6    * distributed with this work for additional information
7    * regarding copyright ownership.  The ASF licenses this file
8    * to you under the Apache License, Version 2.0 (the
9    * "License"); you may not use this file except in compliance
10   * with the License.  You may obtain a copy of the License at
11   *
12   *     http://www.apache.org/licenses/LICENSE-2.0
13   *
14   * Unless required by applicable law or agreed to in writing,
15   * software distributed under the License is distributed on an
16   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17   * KIND, either express or implied.  See the License for the
18   * specific language governing permissions and limitations
19   * under the License.
20   */
21  
22  import java.net.URL;
23  import java.net.URLClassLoader;
24  import java.util.HashSet;
25  import java.util.Set;
26  
27  /**
28   * @noinspection CustomClassloader
29   */
30  public class IsolatedClassLoader
31      extends URLClassLoader
32  {
33      private final ClassLoader parent = ClassLoader.getSystemClassLoader();
34  
35      private final Set<URL> urls = new HashSet<URL>();
36  
37      private final String roleName;
38  
39      private boolean childDelegation = true;
40  
41      private static final URL[] EMPTY_URL_ARRAY = new URL[0];
42  
43      public IsolatedClassLoader( ClassLoader parent, boolean childDelegation, String roleName )
44      {
45          super( EMPTY_URL_ARRAY, parent );
46  
47          this.childDelegation = childDelegation;
48  
49          this.roleName = roleName;
50      }
51  
52      public void addURL( URL url )
53      {
54          // avoid duplicates
55          if ( !urls.contains( url ) )
56          {
57              super.addURL( url );
58              urls.add( url );
59          }
60      }
61  
62      public synchronized Class loadClass( String name )
63          throws ClassNotFoundException
64      {
65          Class c;
66  
67          if ( childDelegation )
68          {
69              c = findLoadedClass( name );
70  
71              ClassNotFoundException ex = null;
72  
73              if ( c == null )
74              {
75                  try
76                  {
77                      c = findClass( name );
78                  }
79                  catch ( ClassNotFoundException e )
80                  {
81                      ex = e;
82  
83                      if ( parent != null )
84                      {
85                          c = parent.loadClass( name );
86                      }
87                  }
88              }
89  
90              if ( c == null )
91              {
92                  throw ex;
93              }
94          }
95          else
96          {
97              c = super.loadClass( name );
98          }
99  
100         return c;
101     }
102 
103     public String toString()
104     {
105         return "IsolatedClassLoader{roleName='" + roleName + "'}";
106     }
107 }