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,
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18  * See the License for the specific language governing permissions and
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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      */
CHECKCAST()39     CHECKCAST() {
40     }
41 
42 
43     /** Check whether object is of given type
44      * @param index index to class in constant pool
45      */
CHECKCAST(final int index)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
getExceptions()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
getLoadClassType( final ConstantPoolGen cpg )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
accept( final Visitor v )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 }
89