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