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 */
017package org.apache.bcel.generic;
018
019import org.apache.bcel.Const;
020import org.apache.bcel.ExceptionConst;
021
022/**
023 * Super class for the xRETURN family of instructions.
024 */
025public abstract class ReturnInstruction extends Instruction implements ExceptionThrower, TypedInstruction, StackConsumer {
026
027    /**
028     * Empty constructor needed for Instruction.readInstruction. Not to be used otherwise.
029     */
030    ReturnInstruction() {
031    }
032
033    /**
034     * @param opcode of instruction
035     */
036    protected ReturnInstruction(final short opcode) {
037        super(opcode, (short) 1);
038    }
039
040    @Override
041    public Class<?>[] getExceptions() {
042        return new Class[] {ExceptionConst.ILLEGAL_MONITOR_STATE};
043    }
044
045    public Type getType() {
046        final short opcode = super.getOpcode();
047        switch (opcode) {
048        case Const.IRETURN:
049            return Type.INT;
050        case Const.LRETURN:
051            return Type.LONG;
052        case Const.FRETURN:
053            return Type.FLOAT;
054        case Const.DRETURN:
055            return Type.DOUBLE;
056        case Const.ARETURN:
057            return Type.OBJECT;
058        case Const.RETURN:
059            return Type.VOID;
060        default: // Never reached
061            throw new ClassGenException("Unknown type " + opcode);
062        }
063    }
064
065    /**
066     * @return type associated with the instruction
067     */
068    @Override
069    public Type getType(final ConstantPoolGen cp) {
070        return getType();
071    }
072}