Loader2.java revision 13127:27bd1e39d5fd 
1/*
2 * Copyright (c) 2010, 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
25import java.io.ByteArrayInputStream;
26import java.io.FileInputStream;
27public class Loader2 extends ClassLoader {
28  int _recur;
29  public void print( String msg ) {
30    for( int i=0; i<_recur; i++ )
31      System.out.print("  ");
32    System.out.println(">>Loader2>> "+msg);
33  }
34
35  protected Class findClass2(String name) throws ClassNotFoundException {
36    print("Fetching the implementation of "+name);
37    int old = _recur;
38    try {
39      FileInputStream fi = new FileInputStream(name+".impl2");
40      byte result[] = new byte[fi.available()];
41      fi.read(result);
42
43      print("DefineClass1 on "+name);
44      _recur++;
45      Class clazz = defineClass(name, result, 0, result.length);
46      _recur = old;
47      print("Returning newly loaded class.");
48      return clazz;
49    } catch (Exception e) {
50      _recur = old;
51      print("Not found on disk.");
52      // If we caught an exception, either the class was not found or
53      // it was unreadable by our process.
54      return null;
55      //throw new ClassNotFoundException(e.toString());
56    }
57  }
58
59  protected synchronized Class loadClass(String name, boolean resolve) throws ClassNotFoundException  {
60    // Attempt a disk load first
61    Class c = findClass2(name);
62    if( c == null ) {
63      // check if the class has already been loaded
64      print("Checking for prior loaded class "+name);
65      c = findLoadedClass(name);
66      print("Letting super-loader load "+name);
67      int old = _recur;
68      _recur++;
69      c = super.loadClass(name, false);
70      _recur=old;
71    }
72    if (resolve) { print("Resolving class "+name); resolveClass(c); }
73    print("Returning clazz "+c.getClassLoader()+":"+name);
74    return c;
75  }
76}
77