jef.dna.instructions.impl
Class IfNull

java.lang.Object
  jef.dna.instructions.impl.InstructionAncestor
      jef.dna.instructions.impl.IfNull

All Implemented Interfaces:

java.lang.Cloneable, Instruction, BytesCountable

public class IfNull
extends InstructionAncestor

This class maps the IFNULL bytecode instruction which behaves exactly like the ifnonnull instruction, but the jump happens if and only if the reference popped from the operand stack is null rether then non null.

Author:

Francesco Russo (frusso@cs.unibo.it)

Field Summary

Fields inherited from class jef.dna.instructions.impl.InstructionAncestor

logger, opCode, operands, operandsCount

Constructor Summary

IfNull()
Creates a new instance of IfNull

Method Summary

int	updateRefs(int offset) This method must implement the logic necessary to update all the references to constant pool table's entries contained within the bytecode instruction.

Methods inherited from class jef.dna.instructions.impl.InstructionAncestor

clone, fromArray, getBytesCount, getOpCode, getOperands, getOperandsCount, setOpCode, setOperands, setOperandsCountPosticipated, toArray

Methods inherited from class java.lang.Object

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

Constructor Detail

IfNull

public IfNull()

Creates a new instance of IfNull

Method Detail

updateRefs

public int updateRefs(int offset)

This method must implement the logic necessary to update all the references to constant pool table's entries contained within the bytecode instruction.

Specified by:

updateRefs in interface Instruction

Overrides:

updateRefs in class InstructionAncestor

Parameters:

offset - The offset used for updating expressed as number of cpt's entries to be skipped

Returns:

int The number of processed words within the current bytecode instruction