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1   /*
2    * reserved comment block
3    * DO NOT REMOVE OR ALTER!
4    */
5   package com.sun.org.apache.bcel.internal.generic;
6   
7   /* ====================================================================
8    * The Apache Software License, Version 1.1
9    *
10   * Copyright (c) 2001 The Apache Software Foundation.  All rights
11   * reserved.
12   *
13   * Redistribution and use in source and binary forms, with or without
14   * modification, are permitted provided that the following conditions
15   * are met:
16   *
17   * 1. Redistributions of source code must retain the above copyright
18   *    notice, this list of conditions and the following disclaimer.
19   *
20   * 2. Redistributions in binary form must reproduce the above copyright
21   *    notice, this list of conditions and the following disclaimer in
22   *    the documentation and/or other materials provided with the
23   *    distribution.
24   *
25   * 3. The end-user documentation included with the redistribution,
26   *    if any, must include the following acknowledgment:
27   *       "This product includes software developed by the
28   *        Apache Software Foundation (http://www.apache.org/)."
29   *    Alternately, this acknowledgment may appear in the software itself,
30   *    if and wherever such third-party acknowledgments normally appear.
31   *
32   * 4. The names "Apache" and "Apache Software Foundation" and
33   *    "Apache BCEL" must not be used to endorse or promote products
34   *    derived from this software without prior written permission. For
35   *    written permission, please contact apache@apache.org.
36   *
37   * 5. Products derived from this software may not be called "Apache",
38   *    "Apache BCEL", nor may "Apache" appear in their name, without
39   *    prior written permission of the Apache Software Foundation.
40   *
41   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
42   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
43   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
44   * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
45   * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
46   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
47   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
48   * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
49   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
50   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
51   * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
52   * SUCH DAMAGE.
53   * ====================================================================
54   *
55   * This software consists of voluntary contributions made by many
56   * individuals on behalf of the Apache Software Foundation.  For more
57   * information on the Apache Software Foundation, please see
58   * <http://www.apache.org/>.
59   */
60  
61  import com.sun.org.apache.bcel.internal.Constants;
62  import com.sun.org.apache.bcel.internal.ExceptionConstants;
63  
64  /**
65   * GETFIELD - Fetch field from object
66   * <PRE>Stack: ..., objectref -&gt; ..., value</PRE>
67   * OR
68   * <PRE>Stack: ..., objectref -&gt; ..., value.word1, value.word2</PRE>
69   *
70   * @author  <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
71   */
72  public class GETFIELD extends FieldInstruction
73    implements ExceptionThrower, StackConsumer, StackProducer {
74    /**
75     * Empty constructor needed for the Class.newInstance() statement in
76     * Instruction.readInstruction(). Not to be used otherwise.
77     */
78    GETFIELD() {}
79  
80    public GETFIELD(int index) {
81      super(Constants.GETFIELD, index);
82    }
83  
84    public int produceStack(ConstantPoolGen cpg) { return getFieldSize(cpg); }
85  
86    public Class[] getExceptions() {
87      Class[] cs = new Class[2 + ExceptionConstants.EXCS_FIELD_AND_METHOD_RESOLUTION.length];
88  
89      System.arraycopy(ExceptionConstants.EXCS_FIELD_AND_METHOD_RESOLUTION, 0,
90                       cs, 0, ExceptionConstants.EXCS_FIELD_AND_METHOD_RESOLUTION.length);
91  
92      cs[ExceptionConstants.EXCS_FIELD_AND_METHOD_RESOLUTION.length+1] =
93        ExceptionConstants.INCOMPATIBLE_CLASS_CHANGE_ERROR;
94      cs[ExceptionConstants.EXCS_FIELD_AND_METHOD_RESOLUTION.length] =
95        ExceptionConstants.NULL_POINTER_EXCEPTION;
96  
97      return cs;
98    }
99  
100 
101   /**
102    * Call corresponding visitor method(s). The order is:
103    * Call visitor methods of implemented interfaces first, then
104    * call methods according to the class hierarchy in descending order,
105    * i.e., the most specific visitXXX() call comes last.
106    *
107    * @param v Visitor object
108    */
109   public void accept(Visitor v) {
110     v.visitExceptionThrower(this);
111     v.visitStackConsumer(this);
112     v.visitStackProducer(this);
113     v.visitTypedInstruction(this);
114     v.visitLoadClass(this);
115     v.visitCPInstruction(this);
116     v.visitFieldOrMethod(this);
117     v.visitFieldInstruction(this);
118     v.visitGETFIELD(this);
119   }
120 }