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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  package org.apache.bcel.generic;
18  
19  import org.apache.bcel.ExceptionConst;
20  
21  /**
22   * INSTANCEOF - Determine if object is of given type
23   *
24   * <PRE>
25   * Stack: ..., objectref -&gt; ..., result
26   * </PRE>
27   */
28  public class INSTANCEOF extends CPInstruction implements LoadClass, ExceptionThrower, StackProducer, StackConsumer {
29  
30      /**
31       * Empty constructor needed for Instruction.readInstruction. Not to be used otherwise.
32       */
33      INSTANCEOF() {
34      }
35  
36      public INSTANCEOF(final int index) {
37          super(org.apache.bcel.Const.INSTANCEOF, index);
38      }
39  
40      /**
41       * Call corresponding visitor method(s). The order is: Call visitor methods of implemented interfaces first, then call
42       * methods according to the class hierarchy in descending order, i.e., the most specific visitXXX() call comes last.
43       *
44       * @param v Visitor object
45       */
46      @Override
47      public void accept(final Visitor v) {
48          v.visitLoadClass(this);
49          v.visitExceptionThrower(this);
50          v.visitStackProducer(this);
51          v.visitStackConsumer(this);
52          v.visitTypedInstruction(this);
53          v.visitCPInstruction(this);
54          v.visitINSTANCEOF(this);
55      }
56  
57      @Override
58      public Class<?>[] getExceptions() {
59          return ExceptionConst.createExceptions(ExceptionConst.EXCS.EXCS_CLASS_AND_INTERFACE_RESOLUTION);
60      }
61  
62      @Override
63      public ObjectType getLoadClassType(final ConstantPoolGen cpg) {
64          Type t = getType(cpg);
65          if (t instanceof ArrayType) {
66              t = ((ArrayType) t).getBasicType();
67          }
68          return t instanceof ObjectType ? (ObjectType) t : null;
69      }
70  }