J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2001 Sun Microsystems, Inc. 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. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun in the LICENSE file that accompanied this code. |
| 10 | * |
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 14 | * version 2 for more details (a copy is included in the LICENSE file that |
| 15 | * accompanied this code). |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License version |
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | package sun.misc; |
| 26 | |
| 27 | import java.util.ArrayList; |
| 28 | |
| 29 | /** |
| 30 | * This is an abstract base class which is called by java.lang.ClassLoader |
| 31 | * when ClassFormatError is thrown inside defineClass(). |
| 32 | * |
| 33 | * The purpose of this class is to allow applications (e.g. Java Plug-in) |
| 34 | * to have a chance to transform the byte code from one form to another |
| 35 | * if necessary. |
| 36 | * |
| 37 | * One application of this class is used by Java Plug-in to transform |
| 38 | * malformed JDK 1.1 class file into a well-formed Java 2 class file |
| 39 | * on-the-fly, so JDK 1.1 applets with malformed class file in the |
| 40 | * Internet may run in Java 2 after transformation. |
| 41 | * |
| 42 | * @author Stanley Man-Kit Ho |
| 43 | */ |
| 44 | |
| 45 | public abstract class ClassFileTransformer |
| 46 | { |
| 47 | // Singleton of ClassFileTransformer |
| 48 | // |
| 49 | private static ArrayList transformerList = new ArrayList(); |
| 50 | private static Object[] transformers = new Object[0]; |
| 51 | |
| 52 | /** |
| 53 | * Add the class file transformer object. |
| 54 | * |
| 55 | * @param t Class file transformer instance |
| 56 | */ |
| 57 | public static void add(ClassFileTransformer t) |
| 58 | { |
| 59 | synchronized(transformerList) |
| 60 | { |
| 61 | transformerList.add(t); |
| 62 | transformers = transformerList.toArray(); |
| 63 | } |
| 64 | } |
| 65 | |
| 66 | /** |
| 67 | * Get the array of ClassFileTransformer object. |
| 68 | * |
| 69 | * @return ClassFileTransformer object array |
| 70 | */ |
| 71 | public static Object[] getTransformers() |
| 72 | { |
| 73 | // transformers is not intended to be changed frequently, |
| 74 | // so it is okay to not put synchronized block here |
| 75 | // to speed up performance. |
| 76 | // |
| 77 | return transformers; |
| 78 | } |
| 79 | |
| 80 | |
| 81 | /** |
| 82 | * Transform a byte array from one to the other. |
| 83 | * |
| 84 | * @param b Byte array |
| 85 | * @param off Offset |
| 86 | * @param len Length of byte array |
| 87 | * @return Transformed byte array |
| 88 | */ |
| 89 | public abstract byte[] transform(byte[] b, int off, int len) |
| 90 | throws ClassFormatError; |
| 91 | } |