/*
 * Copyright  2000-2004 The Apache Software Foundation
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 */
package org.apache.bcel.classfile;

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import org.apache.bcel.Constants;

/**
 * This class is derived from the abstract <A
 * HREF="org.apache.bcel.classfile.Constant.html">Constant</A> class and
 * represents a reference to the name and signature of a field or method.
 * 
 * @version $Id: ConstantNameAndType.java 386056 2006-03-15 11:31:56Z tcurdt $
 * @author <A HREF="mailto:m.dahm@gmx.de">M. Dahm</A>
 * @see Constant
 */
public final class ConstantNameAndType extends Constant {

	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;
	private int name_index; // Name of field/method
	private int signature_index; // and its signature.

	/**
	 * Initialize from another object.
	 */
	public ConstantNameAndType(ConstantNameAndType c) {
		this(c.getNameIndex(), c.getSignatureIndex());
	}

	/**
	 * Initialize instance from file data.
	 * 
	 * @param file
	 *            Input stream
	 * @throws IOException
	 */
	ConstantNameAndType(DataInputStream file) throws IOException {
		this(file.readUnsignedShort(), file.readUnsignedShort());
	}

	/**
	 * @param name_index
	 *            Name of field/method
	 * @param signature_index
	 *            and its signature
	 */
	public ConstantNameAndType(int name_index, int signature_index) {
		super(Constants.CONSTANT_NameAndType);
		this.name_index = name_index;
		this.signature_index = signature_index;
	}

	/**
	 * 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
	 */
	@Override
	public void accept(Visitor v) {
		v.visitConstantNameAndType(this);
	}

	/**
	 * Dump name and signature index to file stream in binary format.
	 * 
	 * @param file
	 *            Output file stream
	 * @throws IOException
	 */
	@Override
	public final void dump(DataOutputStream file) throws IOException {
		file.writeByte(tag);
		file.writeShort(name_index);
		file.writeShort(signature_index);
	}

	/**
	 * @return Name index in constant pool of field/method name.
	 */
	public final int getNameIndex() {
		return name_index;
	}

	/**
	 * @return name
	 */
	public final String getName(ConstantPool cp) {
		return cp.constantToString(getNameIndex(), Constants.CONSTANT_Utf8);
	}

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

	/**
	 * @return signature
	 */
	public final String getSignature(ConstantPool cp) {
		return cp
				.constantToString(getSignatureIndex(), Constants.CONSTANT_Utf8);
	}

	/**
	 * @param name_index
	 *            the name index of this constant
	 */
	public final void setNameIndex(int name_index) {
		this.name_index = name_index;
	}

	/**
	 * @param signature_index
	 *            the signature index in the constant pool of this type
	 */
	public final void setSignatureIndex(int signature_index) {
		this.signature_index = signature_index;
	}

	/**
	 * @return String representation
	 */
	@Override
	public final String toString() {
		return super.toString() + "(name_index = " + name_index
				+ ", signature_index = " + signature_index + ")";
	}
}
