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AspectJ tools most notably contains the AspectJ compiler (AJC). AJC applies aspects to Java classes during compilation, fully replacing Javac for plain Java classes and also compiling native AspectJ or annotation-based @AspectJ syntax. Furthermore, AJC can weave aspects into existing class files in a post-compile binary weaving step. This library is a superset of AspectJ weaver and hence also of AspectJ runtime.

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package org.aspectj.apache.bcel.generic;

/* ====================================================================
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2001 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (https://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Apache" and "Apache Software Foundation" and
 *    "Apache BCEL" must not be used to endorse or promote products
 *    derived from this software without prior written permission. For
 *    written permission, please contact [email protected].
 *
 * 5. Products derived from this software may not be called "Apache",
 *    "Apache BCEL", nor may "Apache" appear in their name, without
 *    prior written permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * .
 */

/**
 * 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 M. Dahm
 */
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.
	 *
	 * @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.
	 */
	public void setTarget(InstructionHandle ih) {
		bi.setTarget(ih);
	}

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

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

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