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.Const;
20 import org.apache.bcel.ExceptionConst;
21
22 /**
23 * GETFIELD - Fetch field from object
24 *
25 * <PRE>
26 * Stack: ..., objectref -> ..., value
27 * </PRE>
28 *
29 * OR
30 *
31 * <PRE>
32 * Stack: ..., objectref -> ..., value.word1, value.word2
33 * </PRE>
34 */
35 public class GETFIELD extends FieldInstruction implements ExceptionThrower, StackConsumer, StackProducer {
36
37 /**
38 * Empty constructor needed for Instruction.readInstruction. Not to be used otherwise.
39 */
40 GETFIELD() {
41 }
42
43 public GETFIELD(final int index) {
44 super(Const.GETFIELD, index);
45 }
46
47 /**
48 * Call corresponding visitor method(s). The order is: Call visitor methods of implemented interfaces first, then call
49 * methods according to the class hierarchy in descending order, i.e., the most specific visitXXX() call comes last.
50 *
51 * @param v Visitor object
52 */
53 @Override
54 public void accept(final Visitor v) {
55 v.visitExceptionThrower(this);
56 v.visitStackConsumer(this);
57 v.visitStackProducer(this);
58 v.visitTypedInstruction(this);
59 v.visitLoadClass(this);
60 v.visitCPInstruction(this);
61 v.visitFieldOrMethod(this);
62 v.visitFieldInstruction(this);
63 v.visitGETFIELD(this);
64 }
65
66 @Override
67 public Class<?>[] getExceptions() {
68 return ExceptionConst.createExceptions(ExceptionConst.EXCS.EXCS_FIELD_AND_METHOD_RESOLUTION, ExceptionConst.NULL_POINTER_EXCEPTION,
69 ExceptionConst.INCOMPATIBLE_CLASS_CHANGE_ERROR);
70 }
71
72 @Override
73 public int produceStack(final ConstantPoolGen cpg) {
74 return getFieldSize(cpg);
75 }
76 }