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 * CHECKCAST - Check whether object is of given type 024 * <PRE>Stack: ..., objectref -> ..., objectref</PRE> 025 * 026 * @version $Id: CHECKCAST.java 1812166 2017-10-13 23:48:11Z ggregory $ 027 */ 028public class CHECKCAST extends CPInstruction implements LoadClass, ExceptionThrower, StackProducer, 029 StackConsumer { 030 031 /** 032 * Empty constructor needed for Instruction.readInstruction. 033 * Not to be used otherwise. 034 */ 035 CHECKCAST() { 036 } 037 038 039 /** Check whether object is of given type 040 * @param index index to class in constant pool 041 */ 042 public CHECKCAST(final int index) { 043 super(org.apache.bcel.Const.CHECKCAST, index); 044 } 045 046 047 /** @return exceptions this instruction may cause 048 */ 049 @Override 050 public Class<?>[] getExceptions() { 051 return ExceptionConst.createExceptions(ExceptionConst.EXCS.EXCS_CLASS_AND_INTERFACE_RESOLUTION, 052 ExceptionConst.CLASS_CAST_EXCEPTION); 053 } 054 055 056 @Override 057 public ObjectType getLoadClassType( final ConstantPoolGen cpg ) { 058 Type t = getType(cpg); 059 if (t instanceof ArrayType) { 060 t = ((ArrayType) t).getBasicType(); 061 } 062 return (t instanceof ObjectType) ? (ObjectType) t : null; 063 } 064 065 066 /** 067 * Call corresponding visitor method(s). The order is: 068 * Call visitor methods of implemented interfaces first, then 069 * call methods according to the class hierarchy in descending order, 070 * i.e., the most specific visitXXX() call comes last. 071 * 072 * @param v Visitor object 073 */ 074 @Override 075 public void accept( final Visitor v ) { 076 v.visitLoadClass(this); 077 v.visitExceptionThrower(this); 078 v.visitStackProducer(this); 079 v.visitStackConsumer(this); 080 v.visitTypedInstruction(this); 081 v.visitCPInstruction(this); 082 v.visitCHECKCAST(this); 083 } 084}