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