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 */ 017package org.apache.bcel.generic; 018 019import java.io.DataOutputStream; 020import java.io.IOException; 021 022import org.apache.bcel.classfile.Constant; 023import org.apache.bcel.classfile.ConstantClass; 024import org.apache.bcel.classfile.ConstantPool; 025import org.apache.bcel.util.ByteSequence; 026 027/** 028 * Abstract super class for instructions that use an index into the constant pool such as LDC, INVOKEVIRTUAL, etc. 029 * 030 * @see ConstantPoolGen 031 * @see LDC 032 * @see INVOKEVIRTUAL 033 */ 034public abstract class CPInstruction extends Instruction implements TypedInstruction, IndexedInstruction { 035 036 /** 037 * @deprecated (since 6.0) will be made private; do not access directly, use getter/setter 038 */ 039 @Deprecated 040 protected int index; // index to constant pool 041 042 /** 043 * Empty constructor needed for Instruction.readInstruction. Not to be used otherwise. 044 */ 045 CPInstruction() { 046 } 047 048 /** 049 * @param index to constant pool 050 */ 051 protected CPInstruction(final short opcode, final int index) { 052 super(opcode, (short) 3); 053 setIndex(index); 054 } 055 056 /** 057 * Dump instruction as byte code to stream out. 058 * 059 * @param out Output stream 060 */ 061 @Override 062 public void dump(final DataOutputStream out) throws IOException { 063 out.writeByte(super.getOpcode()); 064 out.writeShort(index); 065 } 066 067 /** 068 * @return index in constant pool referred by this instruction. 069 */ 070 @Override 071 public final int getIndex() { 072 return index; 073 } 074 075 /** 076 * @return type related with this instruction. 077 */ 078 @Override 079 public Type getType(final ConstantPoolGen cpg) { 080 final ConstantPool cp = cpg.getConstantPool(); 081 String name = cp.getConstantString(index, org.apache.bcel.Const.CONSTANT_Class); 082 if (!name.startsWith("[")) { 083 name = "L" + name + ";"; 084 } 085 return Type.getType(name); 086 } 087 088 /** 089 * Read needed data (i.e., index) from file. 090 * 091 * @param bytes input stream 092 * @param wide wide prefix? 093 */ 094 @Override 095 protected void initFromFile(final ByteSequence bytes, final boolean wide) throws IOException { 096 setIndex(bytes.readUnsignedShort()); 097 super.setLength(3); 098 } 099 100 /** 101 * Set the index to constant pool. 102 * 103 * @param index in constant pool. 104 */ 105 @Override 106 public void setIndex(final int index) { // TODO could be package-protected? 107 if (index < 0) { 108 throw new ClassGenException("Negative index value: " + index); 109 } 110 this.index = index; 111 } 112 113 /** 114 * Long output format: 115 * 116 * <name of opcode> "["<opcode number>"]" "("<length of instruction>")" "<"< constant pool 117 * index>">" 118 * 119 * @param verbose long/short format switch 120 * @return mnemonic for instruction 121 */ 122 @Override 123 public String toString(final boolean verbose) { 124 return super.toString(verbose) + " " + index; 125 } 126 127 /** 128 * @return mnemonic for instruction with symbolic references resolved 129 */ 130 @Override 131 public String toString(final ConstantPool cp) { 132 final Constant c = cp.getConstant(index); 133 String str = cp.constantToString(c); 134 if (c instanceof ConstantClass) { 135 str = str.replace('.', '/'); 136 } 137 return org.apache.bcel.Const.getOpcodeName(super.getOpcode()) + " " + str; 138 } 139}