--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jaxp/src/com/sun/org/apache/bcel/internal/generic/InstructionHandle.java Thu Apr 12 08:38:26 2012 -0700
@@ -0,0 +1,287 @@
+/*
+ * 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/>.
+ */
+
+import com.sun.org.apache.bcel.internal.classfile.Utility;
+import java.util.HashSet;
+import java.util.Collection;
+import java.util.HashMap;
+
+/**
+ * Instances of this class give users a handle to the instructions contained in
+ * an InstructionList. Instruction objects may be used more than once within a
+ * list, this is useful because it saves memory and may be much faster.
+ *
+ * Within an InstructionList an InstructionHandle object is wrapped
+ * around all instructions, i.e., it implements a cell in a
+ * doubly-linked list. From the outside only the next and the
+ * previous instruction (handle) are accessible. One
+ * can traverse the list via an Enumeration returned by
+ * InstructionList.elements().
+ *
+ * @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
+ * @see Instruction
+ * @see BranchHandle
+ * @see InstructionList
+ */
+public class InstructionHandle implements java.io.Serializable {
+ InstructionHandle next, prev; // Will be set from the outside
+ Instruction instruction;
+ protected int i_position = -1; // byte code offset of instruction
+ private HashSet targeters;
+ private HashMap attributes;
+
+ public final InstructionHandle getNext() { return next; }
+ public final InstructionHandle getPrev() { return prev; }
+ public final Instruction getInstruction() { return instruction; }
+
+ /**
+ * Replace current instruction contained in this handle.
+ * Old instruction is disposed using Instruction.dispose().
+ */
+ public void setInstruction(Instruction i) { // Overridden in BranchHandle
+ if(i == null)
+ throw new ClassGenException("Assigning null to handle");
+
+ if((this.getClass() != BranchHandle.class) && (i instanceof BranchInstruction))
+ throw new ClassGenException("Assigning branch instruction " + i + " to plain handle");
+
+ if(instruction != null)
+ instruction.dispose();
+
+ instruction = i;
+ }
+
+ /**
+ * Temporarily swap the current instruction, without disturbing
+ * anything. Meant to be used by a debugger, implementing
+ * breakpoints. Current instruction is returned.
+ */
+ public Instruction swapInstruction(Instruction i) {
+ Instruction oldInstruction = instruction;
+ instruction = i;
+ return oldInstruction;
+ }
+
+ /*private*/ protected InstructionHandle(Instruction i) {
+ setInstruction(i);
+ }
+
+ private static InstructionHandle ih_list = null; // List of reusable handles
+
+ /** Factory method.
+ */
+ static final InstructionHandle getInstructionHandle(Instruction i) {
+ if(ih_list == null)
+ return new InstructionHandle(i);
+ else {
+ InstructionHandle ih = ih_list;
+ ih_list = ih.next;
+
+ ih.setInstruction(i);
+
+ return ih;
+ }
+ }
+
+ /**
+ * 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) {
+ i_position += offset;
+ return 0;
+ }
+
+ /** @return the position, i.e., the byte code offset of the contained
+ * instruction. This is accurate only after
+ * InstructionList.setPositions() has been called.
+ */
+ public int getPosition() { return i_position; }
+
+ /** Set the position, i.e., the byte code offset of the contained
+ * instruction.
+ */
+ void setPosition(int pos) { i_position = pos; }
+
+ /** Overridden in BranchHandle
+ */
+ protected void addHandle() {
+ next = ih_list;
+ ih_list = this;
+ }
+
+ /**
+ * Delete contents, i.e., remove user access and make handle reusable.
+ */
+ void dispose() {
+ next = prev = null;
+ instruction.dispose();
+ instruction = null;
+ i_position = -1;
+ attributes = null;
+ removeAllTargeters();
+ addHandle();
+ }
+
+ /** Remove all targeters, if any.
+ */
+ public void removeAllTargeters() {
+ if(targeters != null)
+ targeters.clear();
+ }
+
+ /**
+ * Denote this handle isn't referenced anymore by t.
+ */
+ public void removeTargeter(InstructionTargeter t) {
+ targeters.remove(t);
+ }
+
+ /**
+ * Denote this handle is being referenced by t.
+ */
+ public void addTargeter(InstructionTargeter t) {
+ if(targeters == null)
+ targeters = new HashSet();
+
+ //if(!targeters.contains(t))
+ targeters.add(t);
+ }
+
+ public boolean hasTargeters() {
+ return (targeters != null) && (targeters.size() > 0);
+ }
+
+ /**
+ * @return null, if there are no targeters
+ */
+ public InstructionTargeter[] getTargeters() {
+ if(!hasTargeters())
+ return null;
+
+ InstructionTargeter[] t = new InstructionTargeter[targeters.size()];
+ targeters.toArray(t);
+ return t;
+ }
+
+ /** @return a (verbose) string representation of the contained instruction.
+ */
+ public String toString(boolean verbose) {
+ return Utility.format(i_position, 4, false, ' ') + ": " + instruction.toString(verbose);
+ }
+
+ /** @return a string representation of the contained instruction.
+ */
+ public String toString() {
+ return toString(true);
+ }
+
+ /** Add an attribute to an instruction handle.
+ *
+ * @param key the key object to store/retrieve the attribute
+ * @param attr the attribute to associate with this handle
+ */
+ public void addAttribute(Object key, Object attr) {
+ if(attributes == null)
+ attributes = new HashMap(3);
+
+ attributes.put(key, attr);
+ }
+
+ /** Delete an attribute of an instruction handle.
+ *
+ * @param key the key object to retrieve the attribute
+ */
+ public void removeAttribute(Object key) {
+ if(attributes != null)
+ attributes.remove(key);
+ }
+
+ /** Get attribute of an instruction handle.
+ *
+ * @param key the key object to store/retrieve the attribute
+ */
+ public Object getAttribute(Object key) {
+ if(attributes != null)
+ return attributes.get(key);
+
+ return null;
+ }
+
+ /** @return all attributes associated with this handle
+ */
+ public Collection getAttributes() {
+ return attributes.values();
+ }
+
+ /** Convenience method, simply calls accept() on the contained instruction.
+ *
+ * @param v Visitor object
+ */
+ public void accept(Visitor v) {
+ instruction.accept(v);
+ }
+}