    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 * @version $Id$
    027 */
    028public class INSTANCEOF extends CPInstruction implements LoadClass, ExceptionThrower,
    029        StackProducer, StackConsumer {
    030
    031    /**
    032     * Empty constructor needed for Instruction.readInstruction.
    033     * Not to be used otherwise.
    034     */
    035    INSTANCEOF() {
    036    }
    037
    038
    039    public INSTANCEOF(final int index) {
    040        super(org.apache.bcel.Const.INSTANCEOF, index);
    041    }
    042
    043
    044    @Override
    045    public Class<?>[] getExceptions() {
    046        return ExceptionConst.createExceptions(ExceptionConst.EXCS.EXCS_CLASS_AND_INTERFACE_RESOLUTION);
    047    }
    048
    049
    050    @Override
    051    public ObjectType getLoadClassType( final ConstantPoolGen cpg ) {
    052        Type t = getType(cpg);
    053        if (t instanceof ArrayType) {
    054            t = ((ArrayType) t).getBasicType();
    055        }
    056        return (t instanceof ObjectType) ? (ObjectType) t : null;
    057    }
    058
    059
    060    /**
    061     * Call corresponding visitor method(s). The order is:
    062     * Call visitor methods of implemented interfaces first, then
    063     * call methods according to the class hierarchy in descending order,
    064     * i.e., the most specific visitXXX() call comes last.
    065     *
    066     * @param v Visitor object
    067     */
    068    @Override
    069    public void accept( final Visitor v ) {
    070        v.visitLoadClass(this);
    071        v.visitExceptionThrower(this);
    072        v.visitStackProducer(this);
    073        v.visitStackConsumer(this);
    074        v.visitTypedInstruction(this);
    075        v.visitCPInstruction(this);
    076        v.visitINSTANCEOF(this);
    077    }
    078}