/*
 * 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.generic;

import org.apache.bcel.Constants;

/**
 * Returnaddress, the type JSR or JSR_W instructions push upon the stack.
 * 
 * see vmspec2 3.3.3
 * 
 * @version $Id: ReturnaddressType.java 386056 2006-03-15 11:31:56Z tcurdt $
 * @author Enver Haase
 */
public class ReturnaddressType extends Type {

	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;
	public static final ReturnaddressType NO_TARGET = new ReturnaddressType();
	private InstructionHandle returnTarget;

	/**
	 * A Returnaddress [that doesn't know where to return to].
	 */
	private ReturnaddressType() {
		super(Constants.T_ADDRESS, "<return address>");
	}

	/**
	 * Creates a ReturnaddressType object with a target.
	 */
	public ReturnaddressType(InstructionHandle returnTarget) {
		super(Constants.T_ADDRESS, "<return address targeting " + returnTarget
				+ ">");
		this.returnTarget = returnTarget;
	}

	/**
	 * @return a hash code value for the object.
	 */
	@Override
	public int hashCode() {
		if (returnTarget == null) {
			return 0;
		}
		return returnTarget.hashCode();
	}

	/**
	 * Returns if the two Returnaddresses refer to the same target.
	 */
	@Override
	public boolean equals(Object rat) {
		if (!(rat instanceof ReturnaddressType)) {
			return false;
		}
		ReturnaddressType that = (ReturnaddressType) rat;
		if (this.returnTarget == null || that.returnTarget == null) {
			return that.returnTarget == this.returnTarget;
		}
		return that.returnTarget.equals(this.returnTarget);
	}

	/**
	 * @return the target of this ReturnaddressType
	 */
	public InstructionHandle getTarget() {
		return returnTarget;
	}
}
