001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 *  Unless required by applicable law or agreed to in writing, software
012 *  distributed under the License is distributed on an "AS IS" BASIS,
013 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 *  See the License for the specific language governing permissions and
015 *  limitations under the License.
016 *
017 */
018package org.apache.bcel.generic;
019
020import org.apache.bcel.Const;
021import org.apache.bcel.ExceptionConst;
022
023/**
024 * Super class for the xRETURN family of instructions.
025 *
026 */
027public abstract class ReturnInstruction extends Instruction implements ExceptionThrower,
028        TypedInstruction, StackConsumer {
029
030    /**
031     * Empty constructor needed for Instruction.readInstruction.
032     * Not to be used otherwise.
033     */
034    ReturnInstruction() {
035    }
036
037
038    /**
039     * @param opcode of instruction
040     */
041    protected ReturnInstruction(final short opcode) {
042        super(opcode, (short) 1);
043    }
044
045
046    public Type getType() {
047        final short _opcode = super.getOpcode();
048        switch (_opcode) {
049            case Const.IRETURN:
050                return Type.INT;
051            case Const.LRETURN:
052                return Type.LONG;
053            case Const.FRETURN:
054                return Type.FLOAT;
055            case Const.DRETURN:
056                return Type.DOUBLE;
057            case Const.ARETURN:
058                return Type.OBJECT;
059            case Const.RETURN:
060                return Type.VOID;
061            default: // Never reached
062                throw new ClassGenException("Unknown type " + _opcode);
063        }
064    }
065
066
067    @Override
068    public Class<?>[] getExceptions() {
069        return new Class[] {
070            ExceptionConst.ILLEGAL_MONITOR_STATE
071        };
072    }
073
074
075    /** @return type associated with the instruction
076     */
077    @Override
078    public Type getType( final ConstantPoolGen cp ) {
079        return getType();
080    }
081}