1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one 3 * or more contributor license agreements. See the NOTICE file 4 * distributed with this work for additional information 5 * regarding copyright ownership. The ASF licenses this file 6 * to you under the Apache License, Version 2.0 (the 7 * "License"); you may not use this file except in compliance 8 * with the License. You may obtain a copy of the License at 9 * 10 * https://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, 13 * software distributed under the License is distributed on an 14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 15 * KIND, either express or implied. See the License for the 16 * specific language governing permissions and limitations 17 * under the License. 18 */ 19 package org.apache.bcel.generic; 20 21 import org.apache.bcel.ExceptionConst; 22 23 /** 24 * CHECKCAST - Check whether object is of given type 25 * 26 * <PRE> 27 * Stack: ..., objectref -> ..., objectref 28 * </PRE> 29 */ 30 public class CHECKCAST extends CPInstruction implements LoadClass, ExceptionThrower, StackProducer, StackConsumer { 31 32 /** 33 * Empty constructor needed for Instruction.readInstruction. Not to be used otherwise. 34 */ 35 CHECKCAST() { 36 } 37 38 /** 39 * Check whether object is of given type 40 * 41 * @param index index to class in constant pool 42 */ 43 public CHECKCAST(final int index) { 44 super(org.apache.bcel.Const.CHECKCAST, index); 45 } 46 47 /** 48 * Call corresponding visitor method(s). The order is: Call visitor methods of implemented interfaces first, then call 49 * methods according to the class hierarchy in descending order, i.e., the most specific visitXXX() call comes last. 50 * 51 * @param v Visitor object 52 */ 53 @Override 54 public void accept(final Visitor v) { 55 v.visitLoadClass(this); 56 v.visitExceptionThrower(this); 57 v.visitStackProducer(this); 58 v.visitStackConsumer(this); 59 v.visitTypedInstruction(this); 60 v.visitCPInstruction(this); 61 v.visitCHECKCAST(this); 62 } 63 64 /** 65 * @return exceptions this instruction may cause 66 */ 67 @Override 68 public Class<?>[] getExceptions() { 69 return ExceptionConst.createExceptions(ExceptionConst.EXCS.EXCS_CLASS_AND_INTERFACE_RESOLUTION, ExceptionConst.CLASS_CAST_EXCEPTION); 70 } 71 72 @Override 73 public ObjectType getLoadClassType(final ConstantPoolGen cpg) { 74 Type t = getType(cpg); 75 if (t instanceof ArrayType) { 76 t = ((ArrayType) t).getBasicType(); 77 } 78 return t instanceof ObjectType ? (ObjectType) t : null; 79 } 80 }