1 /*
   2  * Copyright (c) 2009, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 
  24 import java.net.MalformedURLException;
  25 import java.net.URL;
  26 import java.net.URLClassLoader;
  27 import java.util.concurrent.ConcurrentHashMap;
  28 import java.util.concurrent.locks.*;
  29 import java.lang.reflect.*;
  30 
  31 public class DelegatingLoader extends URLClassLoader {
  32 
  33     private DelegatingLoader delLoader;
  34     private String[] delClasses;
  35 
  36     static {
  37         boolean supportParallel = false;
  38         try {
  39             Class c = Class.forName("java.lang.ClassLoader");
  40             Method m = c.getDeclaredMethod("registerAsParallelCapable",
  41                     new Class[0]);
  42             m.setAccessible(true);
  43             Object result = (Boolean) m.invoke(null);
  44             if (result instanceof Boolean) {
  45                 supportParallel = ((Boolean) result).booleanValue();
  46             } else {
  47                 // Should never happen
  48                 System.out.println("Error: ClassLoader.registerAsParallelCapable() did not return a boolean!");
  49                 System.exit(1);
  50             }
  51         } catch (NoSuchMethodException nsme) {
  52             System.out.println("No ClassLoader.registerAsParallelCapable() API");
  53         } catch (NoSuchMethodError nsme2) {
  54             System.out.println("No ClassLoader.registerAsParallelCapable() API");
  55         } catch (Exception ex) {
  56             ex.printStackTrace();
  57             // Exit immediately to indicate an error
  58             System.exit(1);
  59         }
  60         System.out.println("Parallel ClassLoader registration: " +
  61                     supportParallel);
  62     }
  63 
  64     public DelegatingLoader(URL urls[]) {
  65         super(urls);
  66         System.out.println("DelegatingLoader using URL " + urls[0]);
  67     }
  68 
  69     public void setDelegate(String[] delClasses, DelegatingLoader delLoader) {
  70         this.delClasses = delClasses;
  71         this.delLoader = delLoader;
  72     }
  73 
  74     public Class loadClass(String className, boolean resolve)
  75             throws ClassNotFoundException {
  76         for (int i = 0; i < delClasses.length; i++) {
  77             if (delClasses[i].equals(className)) {
  78                 DelegateTest.log("Delegating class loading for " + className);
  79                 try {
  80                     Thread.sleep(500);
  81                 } catch (InterruptedException ie) {
  82                     return null;
  83                 }
  84                 return delLoader.loadClass(className, resolve);
  85             }
  86         }
  87 
  88         DelegateTest.log("Loading local class " + className);
  89 //        synchronized (getClassLoadingLock(className)) {
  90             return super.loadClass(className, resolve);
  91 //        }
  92     }
  93 }