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1: /* ClassFileTransformer.java -- Implementation of this interface is used by an agent to 2: transform class files. 3: Copyright (C) 2005 Free Software Foundation, Inc. 4: 5: This file is part of GNU Classpath. 6: 7: GNU Classpath is free software; you can redistribute it and/or modify 8: it under the terms of the GNU General Public License as published by 9: the Free Software Foundation; either version 2, or (at your option) 10: any later version. 11: 12: GNU Classpath is distributed in the hope that it will be useful, but 13: WITHOUT ANY WARRANTY; without even the implied warranty of 14: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15: General Public License for more details. 16: 17: You should have received a copy of the GNU General Public License 18: along with GNU Classpath; see the file COPYING. If not, write to the 19: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 20: 02110-1301 USA. 21: 22: Linking this library statically or dynamically with other modules is 23: making a combined work based on this library. Thus, the terms and 24: conditions of the GNU General Public License cover the whole 25: combination. 26: 27: As a special exception, the copyright holders of this library give you 28: permission to link this library with independent modules to produce an 29: executable, regardless of the license terms of these independent 30: modules, and to copy and distribute the resulting executable under 31: terms of your choice, provided that you also meet, for each linked 32: independent module, the terms and conditions of the license of that 33: module. An independent module is a module which is not derived from 34: or based on this library. If you modify this library, you may extend 35: this exception to your version of the library, but you are not 36: obligated to do so. If you do not wish to do so, delete this 37: exception statement from your version. */ 38: 39: 40: package java.lang.instrument; 41: 42: import java.security.ProtectionDomain; 43: 44: /** 45: * This interface should be implemented by classes wishing to transform 46: * classes bytecode when defining or redefining classes. 47: * 48: * @author Nicolas Geoffray (nicolas.geoffray@menlina.com) 49: * @see Instrumentation 50: * @see Instrumentation#addTransformer(java.lang.instrument.ClassFileTransformer) 51: * @see Instrumentation#removeTransformer(java.lang.instrument.ClassFileTransformer) 52: * @since 1.5 53: */ 54: public interface ClassFileTransformer 55: { 56: 57: /** 58: * Implementation of this method transforms a class by redefining its 59: * bytecodes. Once a ClassFileTransformer object registers itself to the 60: * Instrumentation object, this method will be called each time a class is 61: * defined (<code>ClassLoader.defineClass</code>) or redefined 62: * (<code>Instrumentation.redefineClasses</code>) 63: * @param loader the loader of the class 64: * @param className the name of the class with packages separated with "/" 65: * @param classBeingRedefined the class being redefined if it's the case, 66: * null otherwise 67: * @param protectionDomain the protection domain of the class being defined or 68: * redefined 69: * @param classfileBuffer the input byte buffer in class file format 70: * 71: * @return a class file buffer or null when no transformation has been performed 72: * 73: * @throws IllegalClassFormatException if the byte buffer does not represent 74: * a well-formed class file 75: * @see Instrumentation#redefineClasses(java.lang.instrument.ClassDefinition[]) 76: * 77: */ 78: byte[] transform(ClassLoader loader, 79: String className, 80: Class<?> classBeingRedefined, 81: ProtectionDomain protectionDomain, 82: byte[] classfileBuffer) 83: throws IllegalClassFormatException; 84: }