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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 urls = new HashSet();
36  
37      private boolean childDelegation = true;
38  
39      private static final URL[] EMPTY_URL_ARRAY = new URL[0];
40  
41      public IsolatedClassLoader( ClassLoader parent, boolean childDelegation )
42      {
43          super( EMPTY_URL_ARRAY, parent );
44  
45          this.childDelegation = childDelegation;
46      }
47  
48      public void addURL( URL url )
49      {
50          // avoid duplicates
51          if ( !urls.contains( url ) )
52          {
53              super.addURL( url );
54              urls.add( url );
55          }
56      }
57  
58      public synchronized Class loadClass( String name )
59          throws ClassNotFoundException
60      {
61          Class c;
62  
63          if ( childDelegation )
64          {
65              c = findLoadedClass( name );
66  
67              ClassNotFoundException ex = null;
68  
69              if ( c == null )
70              {
71                  try
72                  {
73                      c = findClass( name );
74                  }
75                  catch ( ClassNotFoundException e )
76                  {
77                      ex = e;
78  
79                      if ( parent != null )
80                      {
81                          c = parent.loadClass( name );
82                      }
83                  }
84              }
85  
86              if ( c == null )
87              {
88                  throw ex;
89              }
90          }
91          else
92          {
93              c = super.loadClass( name );
94          }
95  
96          return c;
97      }
98  }