com.ibm.wala.shrikeBT.shrikeCT
Class ClassInstrumenter

java.lang.Object
  com.ibm.wala.shrikeBT.shrikeCT.ClassInstrumenter

public final class ClassInstrumenter
extends java.lang.Object

This class provides a convenient way to instrument every method in a class. It assumes you are using ShrikeCT to read and write classes. It's stateful; initially every method is set to the original code read from the class, but you can then go in and modify the methods.

Nested Class Summary

static interface

ClassInstrumenter.MethodExaminer Implement this interface to instrument every method of a class using visitMethods() below.

Constructor Summary

ClassInstrumenter(byte[] bytes)
Create a class instrumenter from raw bytes.

ClassInstrumenter(ClassReader cr)
Create a class instrumenter from a preinitialized class reader.

Method Summary

MethodData	createEmptyMethodData(java.lang.String name, java.lang.String sig, int access)
void	deleteMethod(int i) Indicate that the method should be deleted from the class.
ClassWriter	emitClass() Create a class which is a copy of the original class but with the new method code.
void	enableFakeLineNumbers(int offset) Calling this means that methods without line numbers get fake line numbers added: each bytecode instruction is treated as at line 'offset' + the offset of the instruction.
CodeReader	getMethodCode(int i) Get the original code resource for the method.
ClassReader	getReader()
boolean	isChanged() Check whether any methods in the class have actually been changed.
void	newMethod(MethodData md, ClassWriter classWriter, ClassWriter.Element rawLines)
void	newMethod(java.lang.String name, java.lang.String sig, java.util.ArrayList<Instruction> instructions, int access, ClassWriter classWriter, ClassWriter.Element rawLines) Xiangyu
void	replaceMethod(int i, MethodData md) Replace the code for method i with new code.
void	resetMethod(int i) Reset method i back to the code from the original class, and "undelete" it if it was marked for deletion.
MethodData	visitMethod(int i) Get the current state of method i.
void	visitMethods(ClassInstrumenter.MethodExaminer me) Do something to every method in the class.

Methods inherited from class java.lang.Object

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

Constructor Detail

ClassInstrumenter

public ClassInstrumenter(byte[] bytes)
                  throws InvalidClassFileException

Create a class instrumenter from raw bytes.

Throws:

InvalidClassFileException

ClassInstrumenter

public ClassInstrumenter(ClassReader cr)
                  throws InvalidClassFileException

Create a class instrumenter from a preinitialized class reader.

Throws:

java.lang.IllegalArgumentException - if cr is null

InvalidClassFileException

Method Detail

enableFakeLineNumbers

public void enableFakeLineNumbers(int offset)

Calling this means that methods without line numbers get fake line numbers added: each bytecode instruction is treated as at line 'offset' + the offset of the instruction.

getReader

public ClassReader getReader()

Returns:

the reader for the class

deleteMethod

public void deleteMethod(int i)

Indicate that the method should be deleted from the class.

Parameters:

i - the index of the method to delete

createEmptyMethodData

public MethodData createEmptyMethodData(java.lang.String name,
                                        java.lang.String sig,
                                        int access)

newMethod

public void newMethod(java.lang.String name,
                      java.lang.String sig,
                      java.util.ArrayList<Instruction> instructions,
                      int access,
                      ClassWriter classWriter,
                      ClassWriter.Element rawLines)

Xiangyu

Throws:

java.lang.IllegalArgumentException - if classWriter is null

java.lang.IllegalArgumentException - if instructions is null

newMethod

public void newMethod(MethodData md,
                      ClassWriter classWriter,
                      ClassWriter.Element rawLines)

visitMethods

public void visitMethods(ClassInstrumenter.MethodExaminer me)
                  throws InvalidClassFileException

Do something to every method in the class. This will visit all methods, including those already marked for deletion.

Parameters:

me - the visitor to apply to each method

Throws:

InvalidClassFileException

visitMethod

public MethodData visitMethod(int i)
                       throws InvalidClassFileException

Get the current state of method i. This can be edited using a MethodEditor.

Parameters:

i - the index of the method to inspect

Throws:

InvalidClassFileException

getMethodCode

public CodeReader getMethodCode(int i)
                         throws InvalidClassFileException

Get the original code resource for the method.

Parameters:

i - the index of the method to inspect

Throws:

InvalidClassFileException

resetMethod

public void resetMethod(int i)

Reset method i back to the code from the original class, and "undelete" it if it was marked for deletion.

Parameters:

i - the index of the method to reset

replaceMethod

public void replaceMethod(int i,
                          MethodData md)

Replace the code for method i with new code. This also "undeletes" the method if it was marked for deletion.

Parameters:

i - the index of the method to replace

Throws:

java.lang.IllegalArgumentException - if md is null

isChanged

public boolean isChanged()

Check whether any methods in the class have actually been changed.

emitClass

public ClassWriter emitClass()
                      throws InvalidClassFileException

Create a class which is a copy of the original class but with the new method code. We return the ClassWriter used, so more methods and fields (and other changes) can still be added. We fix up any debug information to be consistent with the changes to the code.

Throws:

InvalidClassFileException