org.jboss.util.loading

Interface Translator

public interface Translator

An interface for transforming byte code before Class creation. This is compatible with the JDK1.5 java.lang.instrument.ClassFileTransformer proposal.

Version:

$Revision$

Method Summary

Modifier and Type	Method and Description
byte[]	transform(java.lang.ClassLoader loader, java.lang.String className, java.lang.Class<?> classBeingRedefined, java.security.ProtectionDomain protectionDomain, byte[] classfileBuffer) Optionally transform the supplied class file and return a new replacement class file.
void	unregisterClassLoader(java.lang.ClassLoader loader) Called to indicate that the ClassLoader is being discarded by the server.

Method Detail

transform

byte[] transform(java.lang.ClassLoader loader,
                 java.lang.String className,
                 java.lang.Class<?> classBeingRedefined,
                 java.security.ProtectionDomain protectionDomain,
                 byte[] classfileBuffer)
          throws java.lang.Exception

Optionally transform the supplied class file and return a new replacement class file.

If a transformer has been registered with the class loading layer, the transformer will be called for every new class definition. The request for a new class definition is made with defineClass The transformer is called during the processing of the request, before the class file bytes have been verified or applied.

If the implementing method determines that no transformations are needed, it should return null. Otherwise, it should create a new byte[] array and copy the input classfileBuffer into it, along with all desired transformations. The input classfileBuffer must not be modified.

Parameters:

loader - - the defining loader of the class to be transformed, may be null if the bootstrap loader

className - - the fully-qualified name of the class

classBeingRedefined - - if this is a redefine, the class being redefined, otherwise null

protectionDomain - - the protection domain of the class being defined or redefined

classfileBuffer - - the input byte buffer in class file format - must not be modified

Returns:

a well-formed class file buffer (the result of the transform), or null if no transform is performed.

Throws:

java.lang.Exception - - if the input does not represent a well-formed class file

unregisterClassLoader

void unregisterClassLoader(java.lang.ClassLoader loader)

Called to indicate that the ClassLoader is being discarded by the server.

Parameters:

loader - - a class loader that has possibly been used previously as an argument to transform.