javax.persistence.spi
Interface ClassTransformer

public interface ClassTransformer

A persistence provider supplies an instance of this interface to the PersistenceUnitInfo.addTransformer method. The supplied transformer instance will get called to transform entity class files when they are loaded or redefined. The transformation occurs before the class is defined by the JVM.

Since:

Java Persistence 1.0

Method Summary

byte[]

transform(java.lang.ClassLoader loader, java.lang.String className, java.lang.Class<?> classBeingRedefined, java.security.ProtectionDomain protectionDomain, byte[] classfileBuffer) Invoked when a class is being loaded or redefined.

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.instrument.IllegalClassFormatException

Invoked when a class is being loaded or redefined. The implementation of this method may transform the supplied class file and return a new replacement class file.

Parameters:

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

className - the name of the class in the internal form of fully qualified class and interface names

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.instrument.IllegalClassFormatException - if the input does not represent a well-formed class file