net.lenni0451.classtransform

Class TransformerManager

java.lang.Object

net.lenni0451.classtransform.TransformerManager

All Implemented Interfaces:

java.lang.instrument.ClassFileTransformer

public class TransformerManager
extends java.lang.Object
implements java.lang.instrument.ClassFileTransformer

Constructor Summary

Constructors

Constructor and Description
TransformerManager(IClassProvider classProvider)
TransformerManager(IClassProvider classProvider, AMapper mapper)

Method Summary

Modifier and Type	Method and Description
void	addBytecodeTransformer(IBytecodeTransformer bytecodeTransformer) Add a bytecode transformer to the transformer list Useful when needing to modify bytecode directly without ASM parsing or all Classes at once
void	addPostTransformConsumer(IPostTransformer consumer) Add a post transform consumer to handle the raw byte array after all transformer have been applied Useful for dumping transformed classes to disk
void	addRawTransformer(java.lang.String className, IRawTransformer rawTransformer) Add a raw class transformer to the transformer list Useful when needing direct access to a ClassNode
void	addTransformer(org.objectweb.asm.tree.ClassNode classNode) Add a ClassNode directly to the transformer list The class must still be annotated with CTransformer
void	addTransformer(java.lang.String transformer) Add a transformer class to the transformer list Use the direct class name for a single transformer (e.g.
java.util.List<java.lang.String>	getTransformedClasses() Get a list of all transformed classes This is useful to redefine already loaded classes
void	hookInstrumentation(java.lang.instrument.Instrumentation instrumentation) Hook an Instrumentation instance to allow for transformation using it This can be used to transform classes already loaded by the JVM You have to be careful with re-transforming classes since you can't modify the structure (e.g.
byte[]	transform(java.lang.ClassLoader loader, java.lang.String className, java.lang.Class<?> classBeingRedefined, java.security.ProtectionDomain protectionDomain, byte[] classfileBuffer) Support method for Instrumentation You can simply add the TransformerManager as a ClassFileTransformer using Instrumentation.addTransformer(ClassFileTransformer) or call hookInstrumentation(Instrumentation)
byte[]	transform(java.lang.String name, byte[] bytecode) Transform the bytecode of a given class

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

TransformerManager

public TransformerManager(IClassProvider classProvider)

Parameters:

classProvider - The ClassLoader to use for transformer loading

TransformerManager

public TransformerManager(IClassProvider classProvider,
                          AMapper mapper)

Parameters:

classProvider - The ClassLoader to use for transformer loading

mapper - The AMapper instance

Method Detail

addBytecodeTransformer

public void addBytecodeTransformer(IBytecodeTransformer bytecodeTransformer)

Add a bytecode transformer to the transformer list
Useful when needing to modify bytecode directly without ASM parsing or all Classes at once

Parameters:

bytecodeTransformer - The IBytecodeTransformer instance

addRawTransformer

public void addRawTransformer(java.lang.String className,
                              IRawTransformer rawTransformer)

Add a raw class transformer to the transformer list
Useful when needing direct access to a ClassNode

Parameters:

className - The name of the transformer target

rawTransformer - The IRawTransformer instance

addTransformer

public void addTransformer(java.lang.String transformer)

Add a transformer class to the transformer list
Use the direct class name for a single transformer (e.g. package.Transformer)
Use the package ending with '*' for all transformer in the packet (not sub packages) (e.g. package.*)
Use the package ending with '**' for all transformer in the package and sub packages (e.g. package.**)

Parameters:

transformer - The name of transformer class to add

addTransformer

public void addTransformer(org.objectweb.asm.tree.ClassNode classNode)

Add a ClassNode directly to the transformer list
The class must still be annotated with CTransformer

Parameters:

classNode - The ClassNode to add

addPostTransformConsumer

public void addPostTransformConsumer(IPostTransformer consumer)

Add a post transform consumer to handle the raw byte array after all transformer have been applied
Useful for dumping transformed classes to disk

Parameters:

consumer - The BiConsumer instance

transform

public byte[] transform(java.lang.String name,
                        byte[] bytecode)

Transform the bytecode of a given class

Parameters:

name - The name of the class

bytecode - The bytecode of the class

Returns:

The modified bytecode of the class (if there were transformer present)

getTransformedClasses

public java.util.List<java.lang.String> getTransformedClasses()

Get a list of all transformed classes
This is useful to redefine already loaded classes

hookInstrumentation

public void hookInstrumentation(java.lang.instrument.Instrumentation instrumentation)
                         throws java.lang.instrument.UnmodifiableClassException

Hook an Instrumentation instance to allow for transformation using it
This can be used to transform classes already loaded by the JVM
You have to be careful with re-transforming classes since you can't modify the structure (e.g. adding a new method or modifying the signature of an existing one)

Parameters:

instrumentation - The instance of the Instrumentation

Throws:

java.lang.instrument.UnmodifiableClassException - If a class could not be redefined

transform

public 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

Support method for Instrumentation
You can simply add the TransformerManager as a ClassFileTransformer using Instrumentation.addTransformer(ClassFileTransformer) or call hookInstrumentation(Instrumentation)

Specified by:

transform in interface java.lang.instrument.ClassFileTransformer

Throws:

java.lang.instrument.IllegalClassFormatException