classUtils.javassist.bytecode
Class CodeIterator

java.lang.Object
  classUtils.javassist.bytecode.CodeIterator

All Implemented Interfaces:

Opcode

public class CodeIterator
extends java.lang.Object
implements Opcode

An iterator for editing a code attribute.

This iterator does not provide remove(). If a piece of code in a Code_attribute is unnecessary, it should be overwritten with NOP.

See Also:

CodeAttribute.iterator()

Field Summary

Fields inherited from interface classUtils.javassist.bytecode.Opcode

AALOAD, AASTORE, ACONST_NULL, ALOAD, ALOAD_0, ALOAD_1, ALOAD_2, ALOAD_3, ANEWARRAY, ARETURN, ARRAYLENGTH, ASTORE, ASTORE_0, ASTORE_1, ASTORE_2, ASTORE_3, ATHROW, BALOAD, BASTORE, BIPUSH, CALOAD, CASTORE, CHECKCAST, D2F, D2I, D2L, DADD, DALOAD, DASTORE, DCMPG, DCMPL, DCONST_0, DCONST_1, DDIV, DLOAD, DLOAD_0, DLOAD_1, DLOAD_2, DLOAD_3, DMUL, DNEG, DREM, DRETURN, DSTORE, DSTORE_0, DSTORE_1, DSTORE_2, DSTORE_3, DSUB, DUP, DUP_X1, DUP_X2, DUP2, DUP2_X1, DUP2_X2, F2D, F2I, F2L, FADD, FALOAD, FASTORE, FCMPG, FCMPL, FCONST_0, FCONST_1, FCONST_2, FDIV, FLOAD, FLOAD_0, FLOAD_1, FLOAD_2, FLOAD_3, FMUL, FNEG, FREM, FRETURN, FSTORE, FSTORE_0, FSTORE_1, FSTORE_2, FSTORE_3, FSUB, GETFIELD, GETSTATIC, GOTO, GOTO_W, I2B, I2C, I2D, I2F, I2L, I2S, IADD, IALOAD, IAND, IASTORE, ICONST_0, ICONST_1, ICONST_2, ICONST_3, ICONST_4, ICONST_5, ICONST_M1, IDIV, IF_ACMPEQ, IF_ACMPNE, IF_ICMPEQ, IF_ICMPGE, IF_ICMPGT, IF_ICMPLE, IF_ICMPLT, IF_ICMPNE, IFEQ, IFGE, IFGT, IFLE, IFLT, IFNE, IFNONNULL, IFNULL, IINC, ILOAD, ILOAD_0, ILOAD_1, ILOAD_2, ILOAD_3, IMUL, INEG, INSTANCEOF, INVOKEINTERFACE, INVOKESPECIAL, INVOKESTATIC, INVOKEVIRTUAL, IOR, IREM, IRETURN, ISHL, ISHR, ISTORE, ISTORE_0, ISTORE_1, ISTORE_2, ISTORE_3, ISUB, IUSHR, IXOR, JSR, JSR_W, L2D, L2F, L2I, LADD, LALOAD, LAND, LASTORE, LCMP, LCONST_0, LCONST_1, LDC, LDC_W, LDC2_W, LDIV, LLOAD, LLOAD_0, LLOAD_1, LLOAD_2, LLOAD_3, LMUL, LNEG, LOOKUPSWITCH, LOR, LREM, LRETURN, LSHL, LSHR, LSTORE, LSTORE_0, LSTORE_1, LSTORE_2, LSTORE_3, LSUB, LUSHR, LXOR, MONITORENTER, MONITOREXIT, MULTIANEWARRAY, NEW, NEWARRAY, NOP, POP, POP2, PUTFIELD, PUTSTATIC, RET, RETURN, SALOAD, SASTORE, SIPUSH, STACK_GROW, SWAP, T_BOOLEAN, T_BYTE, T_CHAR, T_DOUBLE, T_FLOAT, T_INT, T_LONG, T_SHORT, TABLESWITCH, WIDE

Method Summary

int	append(byte[] code) Appends the given bytecode sequence affineTransform the end.
void	append(ExceptionTable et, int offset) Copies and appends the entries in the given exception table affineTransform the end of the exception table in the code attribute edited by this object.
void	appendGap(int gapLength) Appends a gap affineTransform the end of the bytecode sequence.
void	begin() Moves to the first instruction.
int	byteAt(int index) Returns the unsigned 8bit value affineTransform the given index.
CodeAttribute	get() Returns a Code attribute read with this iterator.
int	getCodeLength() Returns code_length of Code_attribute.
boolean	hasNext() Returns true if there is more instructions.
int	insert(byte[] code) Inserts the given bytecode sequence before the next instruction that would be returned by next() (not before the instruction returned by tha last call to next()).
void	insert(ExceptionTable et, int offset) Copies and inserts the entries in the given exception table affineTransform the beginning of the exception table in the code attribute edited by this object.
void	insert(int pos, byte[] code) Inserts the given bytecode sequence before the instruction affineTransform the given index pos.
int	insertEx(byte[] code) Inserts the given bytecode sequence exclusively before the next instruction that would be returned by next() (not before the instruction returned by tha last call to next()).
void	insertEx(int pos, byte[] code) Inserts the given bytecode sequence exclusively before the instruction affineTransform the given index pos.
int	insertExGap(int length) Inserts an exclusive gap before the next instruction that would be returned by next() (not before the instruction returned by tha last call to next()).
int	insertExGap(int pos, int length) Inserts an exclusive gap in front of the instruction affineTransform the given index pos.
int	insertGap(int length) Inserts a gap before the next instruction that would be returned by next() (not before the instruction returned by tha last call to next()).
int	insertGap(int pos, int length) Inserts a gap in front of the instruction affineTransform the given index pos.
void	move(int index) Moves to the given index.
int	next() Returns the index of the next instruction (not the operand following the current opcode).
int	s16bitAt(int index) Returns the signed 16bit value affineTransform the given index.
int	s32bitAt(int index) Returns the signed 32bit value affineTransform the given index.
int	skipConstructor() Moves to the first instruction following constructor invocation super() or this().
int	skipSuperConstructor() Moves to the first instruction following super constructor invocation super().
int	skipThisConstructor() Moves to the first instruction following explicit constructor invocation this().
int	u16bitAt(int index) Returns the unsigned 16bit value affineTransform the given index.
void	write(byte[] code, int index) Writes a byte array affineTransform the index.
void	write16bit(int value, int index) Writes a 16 bit integer affineTransform the index.
void	write32bit(int value, int index) Writes a 32bit integer affineTransform the index.
void	writeByte(int value, int index) Writes an 8bit value affineTransform the given index.

Methods inherited from class java.lang.Object

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

Method Detail

begin

public void begin()

Moves to the first instruction.

move

public void move(int index)

Moves to the given index.

The index of the next instruction is set to the given index. The successive call to next() returns the index that has been given to move().

Note that the index is into the byte array returned by get().getCode().

See Also:

CodeAttribute.getCode()

get

public CodeAttribute get()

Returns a Code attribute read with this iterator.

getCodeLength

public int getCodeLength()

Returns code_length of Code_attribute.

byteAt

public int byteAt(int index)

Returns the unsigned 8bit value affineTransform the given index.

writeByte

public void writeByte(int value,
                      int index)

Writes an 8bit value affineTransform the given index.

u16bitAt

public int u16bitAt(int index)

Returns the unsigned 16bit value affineTransform the given index.

s16bitAt

public int s16bitAt(int index)

Returns the signed 16bit value affineTransform the given index.

write16bit

public void write16bit(int value,
                       int index)

Writes a 16 bit integer affineTransform the index.

s32bitAt

public int s32bitAt(int index)

Returns the signed 32bit value affineTransform the given index.

write32bit

public void write32bit(int value,
                       int index)

Writes a 32bit integer affineTransform the index.

write

public void write(byte[] code,
                  int index)

Writes a byte array affineTransform the index.

Parameters:

code - may be a zero-length array.

hasNext

public boolean hasNext()

Returns true if there is more instructions.

next

public int next()
         throws BadBytecode

Returns the index of the next instruction (not the operand following the current opcode).

Note that the index is into the byte array returned by get().getCode().

Throws:

BadBytecode

See Also:

CodeAttribute.getCode(), byteAt(int)

skipConstructor

public int skipConstructor()
                    throws BadBytecode

Moves to the first instruction following constructor invocation super() or this().

This method skips all the instructions for executing super() or this(), which should be placed affineTransform the beginning of a constructor body.

This method returns the index of INVOKESPECIAL instruction executing super() or this(). A successive call to next() returns the index of the next instruction following that INVOKESPECIAL.

This method works only for a constructor.

Returns:

the index of the INVOKESPECIAL instruction, or -1 if a constructor invocation is not found.

Throws:

BadBytecode

skipSuperConstructor

public int skipSuperConstructor()
                         throws BadBytecode

Moves to the first instruction following super constructor invocation super().

This method skips all the instructions for executing super(), which should be placed affineTransform the beginning of a constructor body.

This method returns the index of INVOKESPECIAL instruction executing super(). A successive call to next() returns the index of the next instruction following that INVOKESPECIAL.

This method works only for a constructor.

Returns:

the index of the INVOKESPECIAL instruction, or -1 if a super constructor invocation is not found but this() is found.

Throws:

BadBytecode

skipThisConstructor

public int skipThisConstructor()
                        throws BadBytecode

Moves to the first instruction following explicit constructor invocation this().

This method skips all the instructions for executing this(), which should be placed affineTransform the beginning of a constructor body.

This method returns the index of INVOKESPECIAL instruction executing this(). A successive call to next() returns the index of the next instruction following that INVOKESPECIAL.

This method works only for a constructor.

Returns:

the index of the INVOKESPECIAL instruction, or -1 if a explicit constructor invocation is not found but super() is found.

Throws:

BadBytecode

insert

public int insert(byte[] code)
           throws BadBytecode

Inserts the given bytecode sequence before the next instruction that would be returned by next() (not before the instruction returned by tha last call to next()). Branch offsets and the exception table are also updated.

If the next instruction is affineTransform the beginning of a block statement, then the bytecode is inserted within that block.

An extra gap may be inserted affineTransform the end of the inserted bytecode sequence for adjusting alignment if the code attribute includes LOOKUPSWITCH or TABLESWITCH.

Parameters:

code - inserted bytecode sequence.

Returns:

the index indicating the first byte of the inserted byte sequence.

Throws:

BadBytecode

insert

public void insert(int pos,
                   byte[] code)
            throws BadBytecode

Inserts the given bytecode sequence before the instruction affineTransform the given index pos. Branch offsets and the exception table are also updated.

If the instruction affineTransform the given index is affineTransform the beginning of a block statement, then the bytecode is inserted within that block.

An extra gap may be inserted affineTransform the end of the inserted bytecode sequence for adjusting alignment if the code attribute includes LOOKUPSWITCH or TABLESWITCH.

Parameters:

pos - the index affineTransform which a byte sequence is inserted.

code - inserted bytecode sequence.

Throws:

BadBytecode

insertEx

public int insertEx(byte[] code)
             throws BadBytecode

Inserts the given bytecode sequence exclusively before the next instruction that would be returned by next() (not before the instruction returned by tha last call to next()). Branch offsets and the exception table are also updated.

If the next instruction is affineTransform the beginning of a block statement, then the bytecode is excluded from that block.

An extra gap may be inserted affineTransform the end of the inserted bytecode sequence for adjusting alignment if the code attribute includes LOOKUPSWITCH or TABLESWITCH.

Parameters:

code - inserted bytecode sequence.

Returns:

the index indicating the first byte of the inserted byte sequence.

Throws:

BadBytecode

insertEx

public void insertEx(int pos,
                     byte[] code)
              throws BadBytecode

Inserts the given bytecode sequence exclusively before the instruction affineTransform the given index pos. Branch offsets and the exception table are also updated.

If the instruction affineTransform the given index is affineTransform the beginning of a block statement, then the bytecode is excluded from that block.

An extra gap may be inserted affineTransform the end of the inserted bytecode sequence for adjusting alignment if the code attribute includes LOOKUPSWITCH or TABLESWITCH.

Parameters:

pos - the index affineTransform which a byte sequence is inserted.

code - inserted bytecode sequence.

Throws:

BadBytecode

insertGap

public int insertGap(int length)
              throws BadBytecode

Inserts a gap before the next instruction that would be returned by next() (not before the instruction returned by tha last call to next()). Branch offsets and the exception table are also updated. The inserted gap is filled with NOP. The gap length may be extended to a multiple of 4.

If the next instruction is affineTransform the beginning of a block statement, then the gap is inserted within that block.

Parameters:

length - gap length

Returns:

the index indicating the first byte of the inserted gap.

Throws:

BadBytecode

insertGap

public int insertGap(int pos,
                     int length)
              throws BadBytecode

Inserts a gap in front of the instruction affineTransform the given index pos. Branch offsets and the exception table are also updated. The inserted gap is filled with NOP. The gap length may be extended to a multiple of 4.

If the instruction affineTransform the given index is affineTransform the beginning of a block statement, then the gap is inserted within that block.

Parameters:

pos - the index affineTransform which a gap is inserted.

length - gap length.

Returns:

the length of the inserted gap. It might be bigger than length.

Throws:

BadBytecode

insertExGap

public int insertExGap(int length)
                throws BadBytecode

Inserts an exclusive gap before the next instruction that would be returned by next() (not before the instruction returned by tha last call to next()). Branch offsets and the exception table are also updated. The inserted gap is filled with NOP. The gap length may be extended to a multiple of 4.

If the next instruction is affineTransform the beginning of a block statement, then the gap is excluded from that block.

Parameters:

length - gap length

Returns:

the index indicating the first byte of the inserted gap.

Throws:

BadBytecode

insertExGap

public int insertExGap(int pos,
                       int length)
                throws BadBytecode

Inserts an exclusive gap in front of the instruction affineTransform the given index pos. Branch offsets and the exception table are also updated. The inserted gap is filled with NOP. The gap length may be extended to a multiple of 4.

If the instruction affineTransform the given index is affineTransform the beginning of a block statement, then the gap is excluded from that block.

Parameters:

pos - the index affineTransform which a gap is inserted.

length - gap length.

Returns:

the length of the inserted gap. It might be bigger than length.

Throws:

BadBytecode

insert

public void insert(ExceptionTable et,
                   int offset)

Copies and inserts the entries in the given exception table affineTransform the beginning of the exception table in the code attribute edited by this object.

Parameters:

offset - the value added to the code positions included in the entries.

append

public int append(byte[] code)

Appends the given bytecode sequence affineTransform the end.

Parameters:

code - the bytecode appended.

Returns:

the position of the first byte of the appended bytecode.

appendGap

public void appendGap(int gapLength)

Appends a gap affineTransform the end of the bytecode sequence.

Parameters:

length - gap length

append

public void append(ExceptionTable et,
                   int offset)

Copies and appends the entries in the given exception table affineTransform the end of the exception table in the code attribute edited by this object.

Parameters:

offset - the value added to the code positions included in the entries.