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 java.io.DataOutputStream; 021import java.io.IOException; 022 023import org.apache.bcel.classfile.Constant; 024import org.apache.bcel.classfile.ConstantClass; 025import org.apache.bcel.classfile.ConstantPool; 026import org.apache.bcel.util.ByteSequence; 027 028/** 029 * Abstract super class for instructions that use an index into the constant pool such as LDC, INVOKEVIRTUAL, etc. 030 * 031 * @see ConstantPoolGen 032 * @see LDC 033 * @see INVOKEVIRTUAL 034 * 035 */ 036public abstract class CPInstruction extends Instruction implements TypedInstruction, IndexedInstruction { 037 038 /** 039 * @deprecated (since 6.0) will be made private; do not access directly, use getter/setter 040 */ 041 @Deprecated 042 protected int index; // index to constant pool 043 044 /** 045 * Empty constructor needed for Instruction.readInstruction. Not to be used otherwise. 046 */ 047 CPInstruction() { 048 } 049 050 /** 051 * @param index to constant pool 052 */ 053 protected CPInstruction(final short opcode, final int index) { 054 super(opcode, (short) 3); 055 setIndex(index); 056 } 057 058 /** 059 * Dump instruction as byte code to stream out. 060 * 061 * @param out Output stream 062 */ 063 @Override 064 public void dump(final DataOutputStream out) throws IOException { 065 out.writeByte(super.getOpcode()); 066 out.writeShort(index); 067 } 068 069 /** 070 * @return index in constant pool referred by this instruction. 071 */ 072 @Override 073 public final int getIndex() { 074 return index; 075 } 076 077 /** 078 * @return type related with this instruction. 079 */ 080 @Override 081 public Type getType(final ConstantPoolGen cpg) { 082 final ConstantPool cp = cpg.getConstantPool(); 083 String name = cp.getConstantString(index, org.apache.bcel.Const.CONSTANT_Class); 084 if (!name.startsWith("[")) { 085 name = "L" + name + ";"; 086 } 087 return Type.getType(name); 088 } 089 090 /** 091 * Read needed data (i.e., index) from file. 092 * 093 * @param bytes input stream 094 * @param wide wide prefix? 095 */ 096 @Override 097 protected void initFromFile(final ByteSequence bytes, final boolean wide) throws IOException { 098 setIndex(bytes.readUnsignedShort()); 099 super.setLength(3); 100 } 101 102 /** 103 * Set the index to constant pool. 104 * 105 * @param index in constant pool. 106 */ 107 @Override 108 public void setIndex(final int index) { // TODO could be package-protected? 109 if (index < 0) { 110 throw new ClassGenException("Negative index value: " + index); 111 } 112 this.index = index; 113 } 114 115 /** 116 * Long output format: 117 * 118 * <name of opcode> "["<opcode number>"]" "("<length of instruction>")" "<"< constant pool 119 * index>">" 120 * 121 * @param verbose long/short format switch 122 * @return mnemonic for instruction 123 */ 124 @Override 125 public String toString(final boolean verbose) { 126 return super.toString(verbose) + " " + index; 127 } 128 129 /** 130 * @return mnemonic for instruction with symbolic references resolved 131 */ 132 @Override 133 public String toString(final ConstantPool cp) { 134 final Constant c = cp.getConstant(index); 135 String str = cp.constantToString(c); 136 if (c instanceof ConstantClass) { 137 str = str.replace('.', '/'); 138 } 139 return org.apache.bcel.Const.getOpcodeName(super.getOpcode()) + " " + str; 140 } 141}