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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.classfile;

/* ====================================================================
 * 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
 * .
 */

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;

import org.aspectj.apache.bcel.Constants;

/**
 * This class represents a local variable within a method. It contains its scope, name, signature and index on the method's frame.
 *
 * @version $Id: LocalVariable.java,v 1.5 2009/09/10 15:35:05 aclement Exp $
 * @author M. Dahm
 * @see LocalVariableTable
 */
public final class LocalVariable implements Constants, Cloneable, Node {

	private int start_pc; // Range in which the variable is valid
	private int length;
	private int name_index; // Index in constant pool of variable name
	private int signature_index; // Index of variable signature
	private int index; /*
						 * Variable is `index'th local variable on this method's frame.
						 */

	private ConstantPool constant_pool;

	/**
	 * Initialize from another object. Note that both objects use the same references (shallow copy). Use copy() for a physical
	 * copy.
	 */
	public LocalVariable(LocalVariable c) {
		this(c.getStartPC(), c.getLength(), c.getNameIndex(), c.getSignatureIndex(), c.getIndex(), c.getConstantPool());
	}

	/**
	 * Construct object from file stream.
	 *
	 * @param file Input stream
	 * @throws IOException
	 */
	LocalVariable(DataInputStream file, ConstantPool constant_pool) throws IOException {
		this(file.readUnsignedShort(), file.readUnsignedShort(), file.readUnsignedShort(), file.readUnsignedShort(), file
				.readUnsignedShort(), constant_pool);
	}

	/**
	 * @param start_pc Range in which the variable
	 * @param length ... is valid
	 * @param name_index Index in constant pool of variable name
	 * @param signature_index Index of variable's signature
	 * @param index Variable is `index'th local variable on the method's frame
	 * @param constant_pool Array of constants
	 */
	public LocalVariable(int start_pc, int length, int name_index, int signature_index, int index, ConstantPool constant_pool) {
		this.start_pc = start_pc;
		this.length = length;
		this.name_index = name_index;
		this.signature_index = signature_index;
		this.index = index;
		this.constant_pool = constant_pool;
	}

	/**
	 * Called by objects that are traversing the nodes of the tree implicitely defined by the contents of a Java class. I.e., the
	 * hierarchy of methods, fields, attributes, etc. spawns a tree of objects.
	 *
	 * @param v Visitor object
	 */
	public void accept(ClassVisitor v) {
		v.visitLocalVariable(this);
	}

	/**
	 * Dump local variable to file stream in binary format.
	 *
	 * @param file Output file stream
	 * @throws IOException
	 */
	public final void dump(DataOutputStream file) throws IOException {
		file.writeShort(start_pc);
		file.writeShort(length);
		file.writeShort(name_index);
		file.writeShort(signature_index);
		file.writeShort(index);
	}

	/**
	 * @return Constant pool used by this object.
	 */
	public final ConstantPool getConstantPool() {
		return constant_pool;
	}

	/**
	 * @return Variable is valid within getStartPC() .. getStartPC()+getLength()
	 */
	public final int getLength() {
		return length;
	}

	/**
	 * @return Variable name.
	 */
	public final String getName() {
		ConstantUtf8 c;

		c = (ConstantUtf8) constant_pool.getConstant(name_index, CONSTANT_Utf8);
		return c.getValue();
	}

	/**
	 * @return Index in constant pool of variable name.
	 */
	public final int getNameIndex() {
		return name_index;
	}

	/**
	 * @return Signature.
	 */
	public final String getSignature() {
		ConstantUtf8 c;
		c = (ConstantUtf8) constant_pool.getConstant(signature_index, CONSTANT_Utf8);
		return c.getValue();
	}

	/**
	 * @return Index in constant pool of variable signature.
	 */
	public final int getSignatureIndex() {
		return signature_index;
	}

	/**
	 * @return index of register where variable is stored
	 */
	public final int getIndex() {
		return index;
	}

	/**
	 * @return Start of range where he variable is valid
	 */
	public final int getStartPC() {
		return start_pc;
	}

	/**
	 * @param constant_pool Constant pool to be used for this object.
	 */
	public final void setConstantPool(ConstantPool constant_pool) {
		this.constant_pool = constant_pool;
	}

	/**
	 * @param length.
	 */
	public final void setLength(int length) {
		this.length = length;
	}

	/**
	 * @param name_index.
	 */
	public final void setNameIndex(int name_index) {
		this.name_index = name_index;
	}

	/**
	 * @param signature_index.
	 */
	public final void setSignatureIndex(int signature_index) {
		this.signature_index = signature_index;
	}

	/**
	 * @param index.
	 */
	public final void setIndex(int index) {
		this.index = index;
	}

	/**
	 * @param start_pc Specify range where the local variable is valid.
	 */
	public final void setStartPC(int start_pc) {
		this.start_pc = start_pc;
	}

	/**
	 * @return string representation.
	 */
	@Override
	public final String toString() {
		String name = getName(), signature = Utility.signatureToString(getSignature());

		return "LocalVariable(start_pc = " + start_pc + ", length = " + length + ", index = " + index + ":" + signature + " "
				+ name + ")";
	}

	/**
	 * @return deep copy of this object
	 */
	public LocalVariable copy() {
		try {
			return (LocalVariable) clone();
		} catch (CloneNotSupportedException e) {
		}

		return null;
	}
}