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1   /*
2    * Copyright  2000-2004 The Apache Software Foundation
3    *
4    *  Licensed under the Apache License, Version 2.0 (the "License"); 
5    *  you may not use this file except in compliance with the License.
6    *  You may obtain a copy of the License at
7    *
8    *      http://www.apache.org/licenses/LICENSE-2.0
9    *
10   *  Unless required by applicable law or agreed to in writing, software
11   *  distributed under the License is distributed on an "AS IS" BASIS,
12   *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   *  See the License for the specific language governing permissions and
14   *  limitations under the License. 
15   *
16   */
17  package org.apache.bcel.generic;
18  
19  /*** 
20   * INSTANCEOF - Determine if object is of given type
21   * <PRE>Stack: ..., objectref -&gt; ..., result</PRE>
22   *
23   * @version $Id: INSTANCEOF.java 386056 2006-03-15 11:31:56Z tcurdt $
24   * @author  <A HREF="mailto:m.dahm@gmx.de">M. Dahm</A>
25   */
26  public class INSTANCEOF extends CPInstruction implements LoadClass, ExceptionThrower,
27          StackProducer, StackConsumer {
28  
29      /***
30       * Empty constructor needed for the Class.newInstance() statement in
31       * Instruction.readInstruction(). Not to be used otherwise.
32       */
33      INSTANCEOF() {
34      }
35  
36  
37      public INSTANCEOF(int index) {
38          super(org.apache.bcel.Constants.INSTANCEOF, index);
39      }
40  
41  
42      public Class[] getExceptions() {
43          return org.apache.bcel.ExceptionConstants.EXCS_CLASS_AND_INTERFACE_RESOLUTION;
44      }
45  
46  
47      public ObjectType getLoadClassType( ConstantPoolGen cpg ) {
48          Type t = getType(cpg);
49          if (t instanceof ArrayType) {
50              t = ((ArrayType) t).getBasicType();
51          }
52          return (t instanceof ObjectType) ? (ObjectType) t : null;
53      }
54  
55  
56      /***
57       * Call corresponding visitor method(s). The order is:
58       * Call visitor methods of implemented interfaces first, then
59       * call methods according to the class hierarchy in descending order,
60       * i.e., the most specific visitXXX() call comes last.
61       *
62       * @param v Visitor object
63       */
64      public void accept( Visitor v ) {
65          v.visitLoadClass(this);
66          v.visitExceptionThrower(this);
67          v.visitStackProducer(this);
68          v.visitStackConsumer(this);
69          v.visitTypedInstruction(this);
70          v.visitCPInstruction(this);
71          v.visitINSTANCEOF(this);
72      }
73  }