package org.aspectj.apache.bcel.generic;

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BranchHandle is returned by specialized InstructionList.append() whenever a BranchInstruction is appended. This is useful when
the target of this instruction is not known at time of creation and must be set later via setTarget().
Author:
M. Dahm
See Also:
InstructionHandle
Instruction
InstructionList
Version:
$Id: BranchHandle.java,v 1.5 2009/10/05 17:35:36 aclement Exp $/**
 * BranchHandle is returned by specialized InstructionList.append() whenever a BranchInstruction is appended. This is useful when
 * the target of this instruction is not known at time of creation and must be set later via setTarget().
 * 
 * @see InstructionHandle
 * @see Instruction
 * @see InstructionList
 * @version $Id: BranchHandle.java,v 1.5 2009/10/05 17:35:36 aclement Exp $
 * @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
 */
public final class BranchHandle extends InstructionHandle {
	private InstructionBranch bi; // An alias in fact, but saves lots of casts

	private BranchHandle(InstructionBranch i) {
		super(i);
		bi = i;
	}

	static final BranchHandle getBranchHandle(InstructionBranch i) {
		return new BranchHandle(i);
	}

	/*
	 * Override InstructionHandle methods: delegate to branch instruction. Through this overriding all access to the private
	 * i_position field should be prevented.
	 */
	public int getPosition() {
		return bi.positionOfThisInstruction;
	}

	void setPosition(int pos) {
		this.pos = bi.positionOfThisInstruction = pos;
	}

	
Called by InstructionList.setPositions when setting the position for every instruction. In the presence of variable length
instructions 'setPositions()' performs multiple passes over the instruction list to calculate the correct (byte) positions
and offsets by calling this function.
Params:
offset – additional offset caused by preceding (variable length) instructions
max_offset – the maximum offset that may be caused by these instructions
Returns:
additional offset caused by possible change of this instruction's length/**
	 * Called by InstructionList.setPositions when setting the position for every instruction. In the presence of variable length
	 * instructions 'setPositions()' performs multiple passes over the instruction list to calculate the correct (byte) positions
	 * and offsets by calling this function.
	 * 
	 * @param offset additional offset caused by preceding (variable length) instructions
	 * @param max_offset the maximum offset that may be caused by these instructions
	 * @return additional offset caused by possible change of this instruction's length
	 */
	protected int updatePosition(int offset, int max_offset) {
		int x = bi.updatePosition(offset, max_offset);
		pos = bi.positionOfThisInstruction;
		return x;
	}

	
Pass new target to instruction.
/**
	 * Pass new target to instruction.
	 */
	public void setTarget(InstructionHandle ih) {
		bi.setTarget(ih);
	}

	
Update target of instruction.
/**
	 * Update target of instruction.
	 */
	public void updateTarget(InstructionHandle old_ih, InstructionHandle new_ih) {
		bi.updateTarget(old_ih, new_ih);
	}

	
Returns:
target of instruction./**
	 * @return target of instruction.
	 */
	public InstructionHandle getTarget() {
		return bi.getTarget();
	}

	
Set new contents. Old instruction is disposed and may not be used anymore.
/**
	 * Set new contents. Old instruction is disposed and may not be used anymore.
	 */
	public void setInstruction(Instruction i) {
		super.setInstruction(i);
		bi = (InstructionBranch) i;
	}
}