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 */ 017 018 package org.apache.commons.net.telnet; 019 020 /** 021 * The TelnetCommand class cannot be instantiated and only serves as a 022 * storehouse for telnet command constants. 023 * @author Daniel F. Savarese 024 * @see org.apache.commons.net.telnet.Telnet 025 * @see org.apache.commons.net.telnet.TelnetClient 026 */ 027 028 public final class TelnetCommand 029 { 030 /*** The maximum value a command code can have. This value is 255. ***/ 031 public static final int MAX_COMMAND_VALUE = 255; 032 033 /*** Interpret As Command code. Value is 255 according to RFC 854. ***/ 034 public static final int IAC = 255; 035 036 /*** Don't use option code. Value is 254 according to RFC 854. ***/ 037 public static final int DONT = 254; 038 039 /*** Request to use option code. Value is 253 according to RFC 854. ***/ 040 public static final int DO = 253; 041 042 /*** Refuse to use option code. Value is 252 according to RFC 854. ***/ 043 public static final int WONT = 252; 044 045 /*** Agree to use option code. Value is 251 according to RFC 854. ***/ 046 public static final int WILL = 251; 047 048 /*** Start subnegotiation code. Value is 250 according to RFC 854. ***/ 049 public static final int SB = 250; 050 051 /*** Go Ahead code. Value is 249 according to RFC 854. ***/ 052 public static final int GA = 249; 053 054 /*** Erase Line code. Value is 248 according to RFC 854. ***/ 055 public static final int EL = 248; 056 057 /*** Erase Character code. Value is 247 according to RFC 854. ***/ 058 public static final int EC = 247; 059 060 /*** Are You There code. Value is 246 according to RFC 854. ***/ 061 public static final int AYT = 246; 062 063 /*** Abort Output code. Value is 245 according to RFC 854. ***/ 064 public static final int AO = 245; 065 066 /*** Interrupt Process code. Value is 244 according to RFC 854. ***/ 067 public static final int IP = 244; 068 069 /*** Break code. Value is 243 according to RFC 854. ***/ 070 public static final int BREAK = 243; 071 072 /*** Data mark code. Value is 242 according to RFC 854. ***/ 073 public static final int DM = 242; 074 075 /*** No Operation code. Value is 241 according to RFC 854. ***/ 076 public static final int NOP = 241; 077 078 /*** End subnegotiation code. Value is 240 according to RFC 854. ***/ 079 public static final int SE = 240; 080 081 /*** End of record code. Value is 239. ***/ 082 public static final int EOR = 239; 083 084 /*** Abort code. Value is 238. ***/ 085 public static final int ABORT = 238; 086 087 /*** Suspend process code. Value is 237. ***/ 088 public static final int SUSP = 237; 089 090 /*** End of file code. Value is 236. ***/ 091 public static final int EOF = 236; 092 093 /*** Synchronize code. Value is 242. ***/ 094 public static final int SYNCH = 242; 095 096 /*** String representations of commands. ***/ 097 private static final String __commandString[] = { 098 "IAC", "DONT", "DO", "WONT", "WILL", "SB", "GA", "EL", "EC", "AYT", 099 "AO", "IP", "BRK", "DMARK", "NOP", "SE", "EOR", "ABORT", "SUSP", "EOF" 100 }; 101 102 private static final int __FIRST_COMMAND = IAC; 103 private static final int __LAST_COMMAND = EOF; 104 105 /*** 106 * Returns the string representation of the telnet protocol command 107 * corresponding to the given command code. 108 * <p> 109 * @param code The command code of the telnet protocol command. 110 * @return The string representation of the telnet protocol command. 111 ***/ 112 public static final String getCommand(int code) 113 { 114 return __commandString[__FIRST_COMMAND - code]; 115 } 116 117 /*** 118 * Determines if a given command code is valid. Returns true if valid, 119 * false if not. 120 * <p> 121 * @param code The command code to test. 122 * @return True if the command code is valid, false if not. 123 **/ 124 public static final boolean isValidCommand(int code) 125 { 126 return (code <= __FIRST_COMMAND && code >= __LAST_COMMAND); 127 } 128 129 // Cannot be instantiated 130 private TelnetCommand() 131 { } 132 }