1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 * 17 */ 18 package org.apache.bcel.generic; 19 20 import org.apache.bcel.ExceptionConst; 21 22 /** 23 * CHECKCAST - Check whether object is of given type 24 * <PRE>Stack: ..., objectref -> ..., objectref</PRE> 25 * 26 * @version $Id$ 27 */ 28 public class CHECKCAST extends CPInstruction implements LoadClass, ExceptionThrower, StackProducer, 29 StackConsumer { 30 31 /** 32 * Empty constructor needed for Instruction.readInstruction. 33 * Not to be used otherwise. 34 */ 35 CHECKCAST() { 36 } 37 38 39 /** Check whether object is of given type 40 * @param index index to class in constant pool 41 */ 42 public CHECKCAST(final int index) { 43 super(org.apache.bcel.Const.CHECKCAST, index); 44 } 45 46 47 /** @return exceptions this instruction may cause 48 */ 49 @Override 50 public Class<?>[] getExceptions() { 51 return ExceptionConst.createExceptions(ExceptionConst.EXCS.EXCS_CLASS_AND_INTERFACE_RESOLUTION, 52 ExceptionConst.CLASS_CAST_EXCEPTION); 53 } 54 55 56 @Override 57 public ObjectType getLoadClassType( final ConstantPoolGen cpg ) { 58 Type t = getType(cpg); 59 if (t instanceof ArrayType) { 60 t = ((ArrayType) t).getBasicType(); 61 } 62 return (t instanceof ObjectType) ? (ObjectType) t : null; 63 } 64 65 66 /** 67 * Call corresponding visitor method(s). The order is: 68 * Call visitor methods of implemented interfaces first, then 69 * call methods according to the class hierarchy in descending order, 70 * i.e., the most specific visitXXX() call comes last. 71 * 72 * @param v Visitor object 73 */ 74 @Override 75 public void accept( final Visitor v ) { 76 v.visitLoadClass(this); 77 v.visitExceptionThrower(this); 78 v.visitStackProducer(this); 79 v.visitStackConsumer(this); 80 v.visitTypedInstruction(this); 81 v.visitCPInstruction(this); 82 v.visitCHECKCAST(this); 83 } 84 } 85
