1 /*
   2  * Copyright (c) 2011, 2018, 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 package vm.mlvm.share;
  25 
  26 import java.io.IOException;
  27 
  28 import vm.share.FileUtils;
  29 
  30 public class CustomClassLoaders {
  31 
  32     public static ClassLoader makeClassBytesLoader(final byte[] classBytes,
  33             final String className) {
  34         return new ClassLoader() {
  35             @Override
  36             protected Class<?> loadClass(String name, boolean resolve) throws ClassNotFoundException {
  37                 Env.traceDebug("Custom loader: requested=" + name + "; can supply=" + className);
  38 
  39                 if (!name.equals(className))
  40                     return super.loadClass(name, resolve);
  41 
  42                 Env.traceDebug("Custom loader: defining " + className + " (" + classBytes.length + ") bytes");
  43 
  44                 return defineClass(className, classBytes, 0, classBytes.length);
  45             }
  46         };
  47     }
  48 
  49     public static ClassLoader makeCustomClassLoader(final String forClassName) throws IOException {
  50         return makeClassBytesLoader(FileUtils.readClass(forClassName), forClassName);
  51     }
  52 }