| /* |
| * reserved comment block |
| * DO NOT REMOVE OR ALTER! |
| */ |
| package com.sun.org.apache.bcel.internal.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 (http://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 apache@apache.org. |
| * |
| * 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 |
| * <http://www.apache.org/>. |
| */ |
| |
| /** |
| * 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 |
| * @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A> |
| */ |
| public final class BranchHandle extends InstructionHandle { |
| private BranchInstruction bi; // An alias in fact, but saves lots of casts |
| |
| private BranchHandle(BranchInstruction i) { |
| super(i); |
| bi = i; |
| } |
| |
| /** Factory methods. |
| */ |
| private static BranchHandle bh_list = null; // List of reusable handles |
| |
| static final BranchHandle getBranchHandle(BranchInstruction i) { |
| if(bh_list == null) |
| return new BranchHandle(i); |
| else { |
| BranchHandle bh = bh_list; |
| bh_list = (BranchHandle)bh.next; |
| |
| bh.setInstruction(i); |
| |
| return bh; |
| } |
| } |
| |
| /** Handle adds itself to the list of resuable handles. |
| */ |
| protected void addHandle() { |
| next = bh_list; |
| bh_list = this; |
| } |
| |
| /* 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.position; } |
| |
| void setPosition(int pos) { |
| i_position = bi.position = pos; |
| } |
| |
| protected int updatePosition(int offset, int max_offset) { |
| int x = bi.updatePosition(offset, max_offset); |
| i_position = bi.position; |
| 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); |
| |
| if(!(i instanceof BranchInstruction)) |
| throw new ClassGenException("Assigning " + i + |
| " to branch handle which is not a branch instruction"); |
| |
| bi = (BranchInstruction)i; |
| } |
| } |