Module jakarta.persistence

Package jakarta.persistence.spi

Interface ClassTransformer

public interface ClassTransformer

A persistence provider supplies an instance of this interface to the PersistenceUnitInfo.addTransformer(jakarta.persistence.spi.ClassTransformer) 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:

1.0

Method Summary

Modifier and Type	Method	Description
byte[]	transform(ClassLoader loader, String className, Class<?> classBeingRedefined, ProtectionDomain protectionDomain, byte[] classfileBuffer)	Invoked when a class is being loaded or redefined.

Method Details

transform

byte[] transform(ClassLoader loader,
 String className,
 Class<?> classBeingRedefined,
 ProtectionDomain protectionDomain,
 byte[] classfileBuffer)
          throws TransformerException

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:

TransformerException - if the input does not represent a well-formed class file