libjava/classpath/java/lang/instrument/ClassFileTransformer.java

   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   /* FIXME[GENERICS]: Class should be Class<?> */
  79   byte[] transform(ClassLoader loader,
  80                  String className,
  81                  Class classBeingRedefined,
  82                  ProtectionDomain protectionDomain,
  83                  byte[] classfileBuffer)
  84                  throws IllegalClassFormatException;
  85 }
  86