/*
 * 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;
import org.apache.bcel.ExceptionConstants;

/**
 * Super class for the xRETURN family of instructions.
 * 
 * @version $Id: ReturnInstruction.java 386056 2006-03-15 11:31:56Z tcurdt $
 * @author <A HREF="mailto:m.dahm@gmx.de">M. Dahm</A>
 */
public abstract class ReturnInstruction extends Instruction implements
		ExceptionThrower, TypedInstruction, StackConsumer {

	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;

	/**
	 * Empty constructor needed for the Class.newInstance() statement in
	 * Instruction.readInstruction(). Not to be used otherwise.
	 */
	ReturnInstruction() {
	}

	/**
	 * @param opcode
	 *            of instruction
	 */
	protected ReturnInstruction(short opcode) {
		super(opcode, (short) 1);
	}

	public Type getType() {
		switch (opcode) {
		case Constants.IRETURN:
			return Type.INT;
		case Constants.LRETURN:
			return Type.LONG;
		case Constants.FRETURN:
			return Type.FLOAT;
		case Constants.DRETURN:
			return Type.DOUBLE;
		case Constants.ARETURN:
			return Type.OBJECT;
		case Constants.RETURN:
			return Type.VOID;
		default: // Never reached
			throw new ClassGenException("Unknown type " + opcode);
		}
	}

	@Override
	public Class<?>[] getExceptions() {
		return new Class[] { ExceptionConstants.ILLEGAL_MONITOR_STATE };
	}

	/**
	 * @return type associated with the instruction
	 */
	@Override
	public Type getType(ConstantPoolGen cp) {
		return getType();
	}
}
