1 /*
   2  * Copyright (c) 2013, 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 com.oracle.java.testlibrary;
  25 
  26 import java.security.SecureClassLoader;
  27 
  28 /**
  29  * {@code ByteCodeLoader} can be used for easy loading of byte code already
  30  * present in memory.
  31  *
  32  * {@code InMemoryCompiler} can be used for compiling source code in a string
  33  * into byte code, which then can be loaded with {@code ByteCodeLoader}.
  34  *
  35  * @see InMemoryCompiler
  36  */
  37 public class ByteCodeLoader extends SecureClassLoader {
  38     private final String className;
  39     private final byte[] byteCode;
  40 
  41     /**
  42      * Creates a new {@code ByteCodeLoader} ready to load a class with the
  43      * given name and the given byte code.
  44      *
  45      * @param className The name of the class
  46      * @param byteCode The byte code of the class
  47      */
  48     public ByteCodeLoader(String className, byte[] byteCode) {
  49         this.className = className;
  50         this.byteCode = byteCode;
  51     }
  52 
  53     @Override
  54     protected Class<?> findClass(String name) throws ClassNotFoundException {
  55         if (!name.equals(className)) {
  56             throw new ClassNotFoundException(name);
  57         }
  58 
  59         return defineClass(name, byteCode, 0, byteCode.length);
  60     }
  61 
  62     /**
  63      * Utility method for creating a new {@code ByteCodeLoader} and then
  64      * directly load the given byte code.
  65      *
  66      * @param className The name of the class
  67      * @param byteCode The byte code for the class
  68      * @throws ClassNotFoundException if the class can't be loaded
  69      * @return A {@see Class} object representing the class
  70      */
  71     public static Class<?> load(String className, byte[] byteCode) throws ClassNotFoundException {
  72         return new ByteCodeLoader(className, byteCode).loadClass(className);
  73     }
  74 }