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Java > Open Source Codes > org > apache > bcel > generic > GETFIELD


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 import org.apache.bcel.Constants;
20 import org.apache.bcel.ExceptionConstants;
21
22 /**
23  * GETFIELD - Fetch field from object
24  * <PRE>Stack: ..., objectref -&gt; ..., value</PRE>
25  * OR
26  * <PRE>Stack: ..., objectref -&gt; ..., value.word1, value.word2</PRE>
27  *
28  * @version $Id: GETFIELD.java 386056 2006-03-15 11:31:56Z tcurdt $
29  * @author <A HREF="mailto:m.dahm@gmx.de">M. Dahm</A>
30  */
31 public class GETFIELD extends FieldInstruction implements ExceptionThrower, StackConsumer,
32         StackProducer {
33
34     /**
35      * Empty constructor needed for the Class.newInstance() statement in
36      * Instruction.readInstruction(). Not to be used otherwise.
37      */
38     GETFIELD() {
39     }
40
41
42     public GETFIELD(int index) {
43         super(Constants.GETFIELD, index);
44     }
45
46
47     public int produceStack( ConstantPoolGen cpg ) {
48         return getFieldSize(cpg);
49     }
50
51
52     public Class JavaDoc[] getExceptions() {
53         Class JavaDoc[] cs = new Class JavaDoc[2 + ExceptionConstants.EXCS_FIELD_AND_METHOD_RESOLUTION.length];
54         System.arraycopy(ExceptionConstants.EXCS_FIELD_AND_METHOD_RESOLUTION, 0, cs, 0,
55                 ExceptionConstants.EXCS_FIELD_AND_METHOD_RESOLUTION.length);
56         cs[ExceptionConstants.EXCS_FIELD_AND_METHOD_RESOLUTION.length + 1] = ExceptionConstants.INCOMPATIBLE_CLASS_CHANGE_ERROR;
57         cs[ExceptionConstants.EXCS_FIELD_AND_METHOD_RESOLUTION.length] = ExceptionConstants.NULL_POINTER_EXCEPTION;
58         return cs;
59     }
60
61
62     /**
63      * Call corresponding visitor method(s). The order is:
64      * Call visitor methods of implemented interfaces first, then
65      * call methods according to the class hierarchy in descending order,
66      * i.e., the most specific visitXXX() call comes last.
67      *
68      * @param v Visitor object
69      */
70     public void accept( Visitor v ) {
71         v.visitExceptionThrower(this);
72         v.visitStackConsumer(this);
73         v.visitStackProducer(this);
74         v.visitTypedInstruction(this);
75         v.visitLoadClass(this);
76         v.visitCPInstruction(this);
77         v.visitFieldOrMethod(this);
78         v.visitFieldInstruction(this);
79         v.visitGETFIELD(this);
80     }
81 }
82
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