001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 * 017 */ 018package org.apache.bcel.generic; 019 020import org.apache.bcel.Const; 021import org.apache.bcel.ExceptionConst; 022 023/** 024 * GETFIELD - Fetch field from object 025 * 026 * <PRE> 027 * Stack: ..., objectref -> ..., value 028 * </PRE> 029 * 030 * OR 031 * 032 * <PRE> 033 * Stack: ..., objectref -> ..., value.word1, value.word2 034 * </PRE> 035 * 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}