1 /*
   2  * reserved comment block
   3  * DO NOT REMOVE OR ALTER!
   4  */
   5 /*
   6  * Licensed to the Apache Software Foundation (ASF) under one or more
   7  * contributor license agreements.  See the NOTICE file distributed with
   8  * this work for additional information regarding copyright ownership.
   9  * The ASF licenses this file to You under the Apache License, Version 2.0
  10  * (the "License"); you may not use this file except in compliance with
  11  * the License.  You may obtain a copy of the License at
  12  *
  13  *      http://www.apache.org/licenses/LICENSE-2.0
  14  *
  15  * Unless required by applicable law or agreed to in writing, software
  16  * distributed under the License is distributed on an "AS IS" BASIS,
  17  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  18  * See the License for the specific language governing permissions and
  19  * limitations under the License.
  20  */
  21 
  22 package com.sun.org.apache.bcel.internal.generic;
  23 
  24 import com.sun.org.apache.bcel.internal.ExceptionConst;
  25 
  26 /**
  27  * CHECKCAST - Check whether object is of given type
  28  * <PRE>Stack: ..., objectref -&gt; ..., objectref</PRE>
  29  *
  30  * @version $Id$
  31  */
  32 public class CHECKCAST extends CPInstruction implements LoadClass, ExceptionThrower, StackProducer,
  33         StackConsumer {
  34 
  35     /**
  36      * Empty constructor needed for Instruction.readInstruction.
  37      * Not to be used otherwise.
  38      */
  39     CHECKCAST() {
  40     }
  41 
  42 
  43     /** Check whether object is of given type
  44      * @param index index to class in constant pool
  45      */
  46     public CHECKCAST(final int index) {
  47         super(com.sun.org.apache.bcel.internal.Const.CHECKCAST, index);
  48     }
  49 
  50 
  51     /** @return exceptions this instruction may cause
  52      */
  53     @Override
  54     public Class<?>[] getExceptions() {
  55         return ExceptionConst.createExceptions(ExceptionConst.EXCS.EXCS_CLASS_AND_INTERFACE_RESOLUTION,
  56             ExceptionConst.CLASS_CAST_EXCEPTION);
  57     }
  58 
  59 
  60     @Override
  61     public ObjectType getLoadClassType( final ConstantPoolGen cpg ) {
  62         Type t = getType(cpg);
  63         if (t instanceof ArrayType) {
  64             t = ((ArrayType) t).getBasicType();
  65         }
  66         return (t instanceof ObjectType) ? (ObjectType) t : null;
  67     }
  68 
  69 
  70     /**
  71      * Call corresponding visitor method(s). The order is:
  72      * Call visitor methods of implemented interfaces first, then
  73      * call methods according to the class hierarchy in descending order,
  74      * i.e., the most specific visitXXX() call comes last.
  75      *
  76      * @param v Visitor object
  77      */
  78     @Override
  79     public void accept( final Visitor v ) {
  80         v.visitLoadClass(this);
  81         v.visitExceptionThrower(this);
  82         v.visitStackProducer(this);
  83         v.visitStackConsumer(this);
  84         v.visitTypedInstruction(this);
  85         v.visitCPInstruction(this);
  86         v.visitCHECKCAST(this);
  87     }
  88 }