1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 18 package org.apache.commons.net.telnet; 19 20 /** 21 * The TelnetCommand class cannot be instantiated and only serves as a 22 * storehouse for telnet command constants. 23 * @author Daniel F. Savarese 24 * @see org.apache.commons.net.telnet.Telnet 25 * @see org.apache.commons.net.telnet.TelnetClient 26 */ 27 28 public final class TelnetCommand 29 { 30 /*** The maximum value a command code can have. This value is 255. ***/ 31 public static final int MAX_COMMAND_VALUE = 255; 32 33 /*** Interpret As Command code. Value is 255 according to RFC 854. ***/ 34 public static final int IAC = 255; 35 36 /*** Don't use option code. Value is 254 according to RFC 854. ***/ 37 public static final int DONT = 254; 38 39 /*** Request to use option code. Value is 253 according to RFC 854. ***/ 40 public static final int DO = 253; 41 42 /*** Refuse to use option code. Value is 252 according to RFC 854. ***/ 43 public static final int WONT = 252; 44 45 /*** Agree to use option code. Value is 251 according to RFC 854. ***/ 46 public static final int WILL = 251; 47 48 /*** Start subnegotiation code. Value is 250 according to RFC 854. ***/ 49 public static final int SB = 250; 50 51 /*** Go Ahead code. Value is 249 according to RFC 854. ***/ 52 public static final int GA = 249; 53 54 /*** Erase Line code. Value is 248 according to RFC 854. ***/ 55 public static final int EL = 248; 56 57 /*** Erase Character code. Value is 247 according to RFC 854. ***/ 58 public static final int EC = 247; 59 60 /*** Are You There code. Value is 246 according to RFC 854. ***/ 61 public static final int AYT = 246; 62 63 /*** Abort Output code. Value is 245 according to RFC 854. ***/ 64 public static final int AO = 245; 65 66 /*** Interrupt Process code. Value is 244 according to RFC 854. ***/ 67 public static final int IP = 244; 68 69 /*** Break code. Value is 243 according to RFC 854. ***/ 70 public static final int BREAK = 243; 71 72 /*** Data mark code. Value is 242 according to RFC 854. ***/ 73 public static final int DM = 242; 74 75 /*** No Operation code. Value is 241 according to RFC 854. ***/ 76 public static final int NOP = 241; 77 78 /*** End subnegotiation code. Value is 240 according to RFC 854. ***/ 79 public static final int SE = 240; 80 81 /*** End of record code. Value is 239. ***/ 82 public static final int EOR = 239; 83 84 /*** Abort code. Value is 238. ***/ 85 public static final int ABORT = 238; 86 87 /*** Suspend process code. Value is 237. ***/ 88 public static final int SUSP = 237; 89 90 /*** End of file code. Value is 236. ***/ 91 public static final int EOF = 236; 92 93 /*** Synchronize code. Value is 242. ***/ 94 public static final int SYNCH = 242; 95 96 /*** String representations of commands. ***/ 97 private static final String __commandString[] = { 98 "IAC", "DONT", "DO", "WONT", "WILL", "SB", "GA", "EL", "EC", "AYT", 99 "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 }