org.aspectj.weaver/source/org/aspectj/apache/bcel/classfile/LocalVariable.java

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 (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
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 *
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 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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 * 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 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 <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
 * @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;
	}
}