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  * INSTANCEOF - Determine if object is of given type
24  * <PRE>Stack: ..., objectref -&gt; ..., result</PRE>
25  *
26  * @version $Id$
27  */
28 public class INSTANCEOF extends CPInstruction implements LoadClass, ExceptionThrower,
29         StackProducer, StackConsumer {
30 
31     /**
32      * Empty constructor needed for Instruction.readInstruction.
33      * Not to be used otherwise.
34      */
INSTANCEOF()35     INSTANCEOF() {
36     }
37 
38 
INSTANCEOF(final int index)39     public INSTANCEOF(final int index) {
40         super(org.apache.bcel.Const.INSTANCEOF, index);
41     }
42 
43 
44     @Override
getExceptions()45     public Class<?>[] getExceptions() {
46         return ExceptionConst.createExceptions(ExceptionConst.EXCS.EXCS_CLASS_AND_INTERFACE_RESOLUTION);
47     }
48 
49 
50     @Override
getLoadClassType( final ConstantPoolGen cpg )51     public ObjectType getLoadClassType( final ConstantPoolGen cpg ) {
52         Type t = getType(cpg);
53         if (t instanceof ArrayType) {
54             t = ((ArrayType) t).getBasicType();
55         }
56         return (t instanceof ObjectType) ? (ObjectType) t : null;
57     }
58 
59 
60     /**
61      * Call corresponding visitor method(s). The order is:
62      * Call visitor methods of implemented interfaces first, then
63      * call methods according to the class hierarchy in descending order,
64      * i.e., the most specific visitXXX() call comes last.
65      *
66      * @param v Visitor object
67      */
68     @Override
accept( final Visitor v )69     public void accept( final Visitor v ) {
70         v.visitLoadClass(this);
71         v.visitExceptionThrower(this);
72         v.visitStackProducer(this);
73         v.visitStackConsumer(this);
74         v.visitTypedInstruction(this);
75         v.visitCPInstruction(this);
76         v.visitINSTANCEOF(this);
77     }
78 }
79