001/* 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * https://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, 013 * software distributed under the License is distributed on an 014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 015 * KIND, either express or implied. See the License for the 016 * specific language governing permissions and limitations 017 * under the License. 018 */ 019package org.apache.bcel.generic; 020 021import org.apache.bcel.ExceptionConst; 022 023/** 024 * CHECKCAST - Check whether object is of given type 025 * 026 * <PRE> 027 * Stack: ..., objectref -> ..., objectref 028 * </PRE> 029 */ 030public class CHECKCAST extends CPInstruction implements LoadClass, ExceptionThrower, StackProducer, StackConsumer { 031 032 /** 033 * Empty constructor needed for Instruction.readInstruction. Not to be used otherwise. 034 */ 035 CHECKCAST() { 036 } 037 038 /** 039 * Check whether object is of given type 040 * 041 * @param index index to class in constant pool 042 */ 043 public CHECKCAST(final int index) { 044 super(org.apache.bcel.Const.CHECKCAST, index); 045 } 046 047 /** 048 * Call corresponding visitor method(s). The order is: Call visitor methods of implemented interfaces first, then call 049 * methods according to the class hierarchy in descending order, i.e., the most specific visitXXX() call comes last. 050 * 051 * @param v Visitor object 052 */ 053 @Override 054 public void accept(final Visitor v) { 055 v.visitLoadClass(this); 056 v.visitExceptionThrower(this); 057 v.visitStackProducer(this); 058 v.visitStackConsumer(this); 059 v.visitTypedInstruction(this); 060 v.visitCPInstruction(this); 061 v.visitCHECKCAST(this); 062 } 063 064 /** 065 * @return exceptions this instruction may cause 066 */ 067 @Override 068 public Class<?>[] getExceptions() { 069 return ExceptionConst.createExceptions(ExceptionConst.EXCS.EXCS_CLASS_AND_INTERFACE_RESOLUTION, ExceptionConst.CLASS_CAST_EXCEPTION); 070 } 071 072 @Override 073 public ObjectType getLoadClassType(final ConstantPoolGen cpg) { 074 Type t = getType(cpg); 075 if (t instanceof ArrayType) { 076 t = ((ArrayType) t).getBasicType(); 077 } 078 return t instanceof ObjectType ? (ObjectType) t : null; 079 } 080}