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java.lang.instrument

Interface ClassFileTransformer

public interface ClassFileTransformer
This interface should be implemented by classes wishing to transform classes bytecode when defining or redefining classes.
Since:
1.5
See Also:
Instrumentation, Instrumentation.addTransformer(ClassFileTransformer), Instrumentation.removeTransformer(ClassFileTransformer)

Method Summary

byte[]
transform(ClassLoader loader, String className, Class classBeingRedefined, ProtectionDomain protectionDomain, byte[] classfileBuffer)
Implementation of this method transforms a class by redefining its bytecodes.

Method Details

transform

public byte[] transform(ClassLoader loader,
                        String className,
                        Class classBeingRedefined,
                        ProtectionDomain protectionDomain,
                        byte[] classfileBuffer)
            throws IllegalClassFormatException
Implementation of this method transforms a class by redefining its bytecodes. Once a ClassFileTransformer object registers itself to the Instrumentation object, this method will be called each time a class is defined (ClassLoader.defineClass) or redefined (Instrumentation.redefineClasses)
Parameters:
loader - the loader of the class
className - the name of the class with packages separated with "/"
classBeingRedefined - the class being redefined if it's the case, null otherwise
protectionDomain - the protection domain of the class being defined or redefined
classfileBuffer - the input byte buffer in class file format
Returns:
a class file buffer or null when no transformation has been performed
Throws:
IllegalClassFormatException - if the byte buffer does not represent a well-formed class file
See Also:
Instrumentation.redefineClasses(ClassDefinition[])
ClassFileTransformer.java -- Implementation of this interface is used by an agent to transform class files. Copyright (C) 2005 Free Software Foundation, Inc. This file is part of GNU Classpath. GNU Classpath is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. GNU Classpath is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with GNU Classpath; see the file COPYING. If not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. Linking this library statically or dynamically with other modules is making a combined work based on this library. Thus, the terms and conditions of the GNU General Public License cover the whole combination. As a special exception, the copyright holders of this library give you permission to link this library with independent modules to produce an executable, regardless of the license terms of these independent modules, and to copy and distribute the resulting executable under terms of your choice, provided that you also meet, for each linked independent module, the terms and conditions of the license of that module. An independent module is a module which is not derived from or based on this library. If you modify this library, you may extend this exception to your version of the library, but you are not obligated to do so. If you do not wish to do so, delete this exception statement from your version.

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