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