old-autovect-branch/libjava/gnu/gcj/runtime/BootClassLoader.java

   1 /* Copyright (C) 2005  Free Software Foundation
   2
   3    This file is part of libgcj.
   4
   5 This software is copyrighted work licensed under the terms of the
   6 Libgcj License.  Please consult the file "LIBGCJ_LICENSE" for
   7 details.  */
   8
   9 package gnu.gcj.runtime;
  10
  11 import java.io.IOException;
  12 import java.net.URL;
  13 import java.util.Enumeration;
  14
  15 /**
  16  * This is a helper for the bootstrap class loader.  It is a
  17  * URLClassLoader so that we can read a class path and re-use all the
  18  * existing code for finding classes, extracting them from jars, etc.
  19  * However, it is never called the way that an ordinary ClassLoader is
  20  * called.  For instance, loadClass() is never used.
  21  */
  22 public final class BootClassLoader extends HelperClassLoader
  23 {
  24   BootClassLoader(String libdir)
  25   {
  26     // The BootClassLoader is the top of the delegation chain. It does not
  27     // have a parent.
  28     super((ClassLoader) null);
  29     addDirectoriesFromProperty("java.endorsed.dirs");
  30     addDirectoriesFromProperty("gnu.gcj.runtime.endorsed.dirs");
  31
  32     try
  33       {
  34         // Add core:/ to the end so any resources compiled into this
  35         // executable may be found.
  36         addURL(new URL("core", "", -1, "/"));
  37       }
  38     catch (java.net.MalformedURLException x)
  39       {
  40         // This should never happen.
  41         throw new RuntimeException(x);
  42       }
  43   }
  44
  45   public Class bootLoadClass(String name)
  46     throws ClassNotFoundException
  47   {
  48     Class c = findLoadedClass(name);
  49     if (c == null)
  50       {
  51         try
  52           {
  53             // We could hack URLClassLoader to make this more
  54             // efficient, if it mattered.
  55             c = findClass(name);
  56           }
  57         catch (ClassNotFoundException _)
  58           {
  59             c = null;
  60           }
  61       }
  62     return c;
  63   }
  64
  65   public URL bootGetResource(String name)
  66   {
  67     return findResource(name);
  68   }
  69
  70   public Enumeration bootGetResources(String name) throws IOException
  71   {
  72     return findResources(name);
  73   }
  74 }