1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * https://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 */
19 package org.apache.bcel.generic;
20
21 import org.apache.bcel.Const;
22 import org.apache.bcel.ExceptionConst;
23
24 /**
25 * GETFIELD - Fetch field from object
26 *
27 * <PRE>
28 * Stack: ..., objectref -> ..., value
29 * </PRE>
30 *
31 * OR
32 *
33 * <PRE>
34 * Stack: ..., objectref -> ..., value.word1, value.word2
35 * </PRE>
36 */
37 public class GETFIELD extends FieldInstruction implements ExceptionThrower, StackConsumer, StackProducer {
38
39 /**
40 * Empty constructor needed for Instruction.readInstruction. Not to be used otherwise.
41 */
42 GETFIELD() {
43 }
44
45 public GETFIELD(final int index) {
46 super(Const.GETFIELD, index);
47 }
48
49 /**
50 * Call corresponding visitor method(s). The order is: Call visitor methods of implemented interfaces first, then call
51 * methods according to the class hierarchy in descending order, i.e., the most specific visitXXX() call comes last.
52 *
53 * @param v Visitor object
54 */
55 @Override
56 public void accept(final Visitor v) {
57 v.visitExceptionThrower(this);
58 v.visitStackConsumer(this);
59 v.visitStackProducer(this);
60 v.visitTypedInstruction(this);
61 v.visitLoadClass(this);
62 v.visitCPInstruction(this);
63 v.visitFieldOrMethod(this);
64 v.visitFieldInstruction(this);
65 v.visitGETFIELD(this);
66 }
67
68 @Override
69 public Class<?>[] getExceptions() {
70 return ExceptionConst.createExceptions(ExceptionConst.EXCS.EXCS_FIELD_AND_METHOD_RESOLUTION, ExceptionConst.NULL_POINTER_EXCEPTION,
71 ExceptionConst.INCOMPATIBLE_CLASS_CHANGE_ERROR);
72 }
73
74 @Override
75 public int produceStack(final ConstantPoolGen cpg) {
76 return getFieldSize(cpg);
77 }
78 }