001/* 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * https://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, 013 * software distributed under the License is distributed on an 014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 015 * KIND, either express or implied. See the License for the 016 * specific language governing permissions and limitations 017 * under the License. 018 */ 019package org.apache.bcel.generic; 020 021import org.apache.bcel.Const; 022import org.apache.bcel.ExceptionConst; 023 024/** 025 * GETFIELD - Fetch field from object 026 * 027 * <PRE> 028 * Stack: ..., objectref -> ..., value 029 * </PRE> 030 * 031 * OR 032 * 033 * <PRE> 034 * Stack: ..., objectref -> ..., value.word1, value.word2 035 * </PRE> 036 */ 037public class GETFIELD extends FieldInstruction implements ExceptionThrower, StackConsumer, StackProducer { 038 039 /** 040 * Empty constructor needed for Instruction.readInstruction. Not to be used otherwise. 041 */ 042 GETFIELD() { 043 } 044 045 public GETFIELD(final int index) { 046 super(Const.GETFIELD, index); 047 } 048 049 /** 050 * Call corresponding visitor method(s). The order is: Call visitor methods of implemented interfaces first, then call 051 * methods according to the class hierarchy in descending order, i.e., the most specific visitXXX() call comes last. 052 * 053 * @param v Visitor object 054 */ 055 @Override 056 public void accept(final Visitor v) { 057 v.visitExceptionThrower(this); 058 v.visitStackConsumer(this); 059 v.visitStackProducer(this); 060 v.visitTypedInstruction(this); 061 v.visitLoadClass(this); 062 v.visitCPInstruction(this); 063 v.visitFieldOrMethod(this); 064 v.visitFieldInstruction(this); 065 v.visitGETFIELD(this); 066 } 067 068 @Override 069 public Class<?>[] getExceptions() { 070 return ExceptionConst.createExceptions(ExceptionConst.EXCS.EXCS_FIELD_AND_METHOD_RESOLUTION, ExceptionConst.NULL_POINTER_EXCEPTION, 071 ExceptionConst.INCOMPATIBLE_CLASS_CHANGE_ERROR); 072 } 073 074 @Override 075 public int produceStack(final ConstantPoolGen cpg) { 076 return getFieldSize(cpg); 077 } 078}