com.techtrader.modules.tools.bytecode
Class JumpInstruction

java.lang.Object
  |
  +--com.techtrader.modules.tools.bytecode.Instruction
        |
        +--com.techtrader.modules.tools.bytecode.JumpInstruction

Direct Known Subclasses:

LookupSwitchInstruction, TableSwitchInstruction

public class JumpInstruction

extends Instruction

implements InstructionPtr

Represents an IF, GOTO, JSR, or similar instruction that specifies as its argument a position in the code block to jump to.

Author:

Abe White

Field Summary

protected int	_offset
protected Instruction	_target

Fields inherited from class com.techtrader.modules.tools.bytecode.Instruction

_byteIndex, _opcode, _opcodeTypes, _owner

Constructor Summary

protected

JumpInstruction(Code owner, int opcode)

Method Summary

void	acceptVisit(BCVisitor visit) Accept a visit from a BCVisitor, calling the appropriate methods to notify the visitor that it has entered this entity, and to provide it with the proper callbacks for each sub-entity owned by this object.
protected void	copy(Instruction orig)
boolean	equals(Object other) JumpInstructions are equal if they represent the same operation and the Instruction they jump to is the same, or if the jump Instruction of either is unset.
int	getLength() Return the length in bytes of this opcode, including all arguments.
int	getOffset() Get the byte offset for the jump instruction.
int	getStackChange() Return the number of stack positions this instruction pushes or pops during its execution.
Instruction	getTarget() Get the current target instruction to jump to, if it has been set.
protected void	readData(DataInput in) Read the arguments for this opcode from the given stream.
void	setMarkers(List instructions) Use the byte indexes read from the .class file to calculate and set references to the target instruction(s) for this ptr.
void	setOffset(int offset) Set the byte offset for the jump instruction.
JumpInstruction	setTarget(Instruction instruction) Set the instruction to jump to; the instruction must already be added to the code block.
protected void	writeData(DataOutput out) Write the arguments for this opcode to the given stream.

Methods inherited from class com.techtrader.modules.tools.bytecode.Instruction

getByteIndex, getName, getOpCode, getOwner, invalidate, setByteIndex, setOpCode

Methods inherited from class java.lang.Object

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

Field Detail

_offset

protected int _offset

_target

protected Instruction _target

Constructor Detail

JumpInstruction

protected JumpInstruction(Code owner,
                          int opcode)

Method Detail

setOffset

public void setOffset(int offset)

Set the byte offset for the jump instruction.

getOffset

public int getOffset()

Get the byte offset for the jump instruction.

setTarget

public JumpInstruction setTarget(Instruction instruction)

Set the instruction to jump to; the instruction must already be added to the code block. WARNING: if this instruction is later deleted from the code block, the results are undefined.

Returns:

this Instruction, for method chaining

getTarget

public Instruction getTarget()

Get the current target instruction to jump to, if it has been set. WARNING: if this instruction is later deleted from the code block, the results are undefined.

setMarkers

public void setMarkers(List instructions)

Description copied from interface: InstructionPtr

Use the byte indexes read from the .class file to calculate and set references to the target instruction(s) for this ptr. This method will be called after the byte code has been read in for the first time.

Specified by:

setMarkers in interface InstructionPtr

Tags copied from interface: InstructionPtr

Parameters:

codes - the list of opcodes in the method

equals

public boolean equals(Object other)

JumpInstructions are equal if they represent the same operation and the Instruction they jump to is the same, or if the jump Instruction of either is unset.

Overrides:

equals in class Instruction

getLength

public int getLength()

Description copied from class: Instruction

Return the length in bytes of this opcode, including all arguments. This method should be overridden by opcodes that take arguments.

Overrides:

getLength in class Instruction

getStackChange

public int getStackChange()

Description copied from class: Instruction

Return the number of stack positions this instruction pushes or pops during its execution.

Overrides:

getStackChange in class Instruction

Tags copied from class: Instruction

Returns:

0 if the stack is not affected by this instruction, a positive number if it pushes onto the stack, and a negative number if it pops from the stack

copy

protected void copy(Instruction orig)

Overrides:

copy in class Instruction

readData

protected void readData(DataInput in)
                 throws IOException

Description copied from class: Instruction

Read the arguments for this opcode from the given stream. This method should be overridden by opcodes that take arguments.

Overrides:

readData in class Instruction

writeData

protected void writeData(DataOutput out)
                  throws IOException

Description copied from class: Instruction

Write the arguments for this opcode to the given stream. This method should be overridden by opcodes that take arguments.

Overrides:

writeData in class Instruction

acceptVisit

public void acceptVisit(BCVisitor visit)

Description copied from interface: VisitAcceptor

Accept a visit from a BCVisitor, calling the appropriate methods to notify the visitor that it has entered this entity, and to provide it with the proper callbacks for each sub-entity owned by this object.

Overrides:

acceptVisit in class Instruction