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.ExceptionConst;
021
022/**
023 * INSTANCEOF - Determine if object is of given type
024 * <PRE>Stack: ..., objectref -&gt; ..., result</PRE>
025 *
026 */
027public class INSTANCEOF extends CPInstruction implements LoadClass, ExceptionThrower,
028        StackProducer, StackConsumer {
029
030    /**
031     * Empty constructor needed for Instruction.readInstruction.
032     * Not to be used otherwise.
033     */
034    INSTANCEOF() {
035    }
036
037
038    public INSTANCEOF(final int index) {
039        super(org.apache.bcel.Const.INSTANCEOF, index);
040    }
041
042
043    @Override
044    public Class<?>[] getExceptions() {
045        return ExceptionConst.createExceptions(ExceptionConst.EXCS.EXCS_CLASS_AND_INTERFACE_RESOLUTION);
046    }
047
048
049    @Override
050    public ObjectType getLoadClassType( final ConstantPoolGen cpg ) {
051        Type t = getType(cpg);
052        if (t instanceof ArrayType) {
053            t = ((ArrayType) t).getBasicType();
054        }
055        return (t instanceof ObjectType) ? (ObjectType) t : null;
056    }
057
058
059    /**
060     * Call corresponding visitor method(s). The order is:
061     * Call visitor methods of implemented interfaces first, then
062     * call methods according to the class hierarchy in descending order,
063     * i.e., the most specific visitXXX() call comes last.
064     *
065     * @param v Visitor object
066     */
067    @Override
068    public void accept( final Visitor v ) {
069        v.visitLoadClass(this);
070        v.visitExceptionThrower(this);
071        v.visitStackProducer(this);
072        v.visitStackConsumer(this);
073        v.visitTypedInstruction(this);
074        v.visitCPInstruction(this);
075        v.visitINSTANCEOF(this);
076    }
077}