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; 019 020/** 021 * Equality of instructions isn't clearly to be defined. You might 022 * wish, for example, to compare whether instructions have the same 023 * meaning. E.g., whether two INVOKEVIRTUALs describe the same 024 * call.<br>The DEFAULT comparator however, considers two instructions 025 * to be equal if they have same opcode and point to the same indexes 026 * (if any) in the constant pool or the same local variable index. Branch 027 * instructions must have the same target. 028 * 029 * @see Instruction 030 * @version $Id: InstructionComparator.java 1749597 2016-06-21 20:28:51Z ggregory $ 031 */ 032public interface InstructionComparator { 033 034 InstructionComparator DEFAULT = new InstructionComparator() { 035 036 @Override 037 public boolean equals( final Instruction i1, final Instruction i2 ) { 038 if (i1.getOpcode() == i2.getOpcode()) { 039 if (i1 instanceof BranchInstruction) { 040 // BIs are never equal to make targeters work correctly (BCEL-195) 041 return false; 042// } else if (i1 == i2) { TODO consider adding this shortcut 043// return true; // this must be AFTER the BI test 044 } else if (i1 instanceof ConstantPushInstruction) { 045 return ((ConstantPushInstruction) i1).getValue().equals( 046 ((ConstantPushInstruction) i2).getValue()); 047 } else if (i1 instanceof IndexedInstruction) { 048 return ((IndexedInstruction) i1).getIndex() == ((IndexedInstruction) i2) 049 .getIndex(); 050 } else if (i1 instanceof NEWARRAY) { 051 return ((NEWARRAY) i1).getTypecode() == ((NEWARRAY) i2).getTypecode(); 052 } else { 053 return true; 054 } 055 } 056 return false; 057 } 058 }; 059 060 061 boolean equals( Instruction i1, Instruction i2 ); 062}