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 * @see org.apache.commons.net.telnet.Telnet
24 * @see org.apache.commons.net.telnet.TelnetClient
25 */
26
27 public final class TelnetCommand
28 {
29 /*** The maximum value a command code can have. This value is 255. ***/
30 public static final int MAX_COMMAND_VALUE = 255;
31
32 /*** Interpret As Command code. Value is 255 according to RFC 854. ***/
33 public static final int IAC = 255;
34
35 /*** Don't use option code. Value is 254 according to RFC 854. ***/
36 public static final int DONT = 254;
37
38 /*** Request to use option code. Value is 253 according to RFC 854. ***/
39 public static final int DO = 253;
40
41 /*** Refuse to use option code. Value is 252 according to RFC 854. ***/
42 public static final int WONT = 252;
43
44 /*** Agree to use option code. Value is 251 according to RFC 854. ***/
45 public static final int WILL = 251;
46
47 /*** Start subnegotiation code. Value is 250 according to RFC 854. ***/
48 public static final int SB = 250;
49
50 /*** Go Ahead code. Value is 249 according to RFC 854. ***/
51 public static final int GA = 249;
52
53 /*** Erase Line code. Value is 248 according to RFC 854. ***/
54 public static final int EL = 248;
55
56 /*** Erase Character code. Value is 247 according to RFC 854. ***/
57 public static final int EC = 247;
58
59 /*** Are You There code. Value is 246 according to RFC 854. ***/
60 public static final int AYT = 246;
61
62 /*** Abort Output code. Value is 245 according to RFC 854. ***/
63 public static final int AO = 245;
64
65 /*** Interrupt Process code. Value is 244 according to RFC 854. ***/
66 public static final int IP = 244;
67
68 /*** Break code. Value is 243 according to RFC 854. ***/
69 public static final int BREAK = 243;
70
71 /*** Data mark code. Value is 242 according to RFC 854. ***/
72 public static final int DM = 242;
73
74 /*** No Operation code. Value is 241 according to RFC 854. ***/
75 public static final int NOP = 241;
76
77 /*** End subnegotiation code. Value is 240 according to RFC 854. ***/
78 public static final int SE = 240;
79
80 /*** End of record code. Value is 239. ***/
81 public static final int EOR = 239;
82
83 /*** Abort code. Value is 238. ***/
84 public static final int ABORT = 238;
85
86 /*** Suspend process code. Value is 237. ***/
87 public static final int SUSP = 237;
88
89 /*** End of file code. Value is 236. ***/
90 public static final int EOF = 236;
91
92 /*** Synchronize code. Value is 242. ***/
93 public static final int SYNCH = 242;
94
95 /*** String representations of commands. ***/
96 private static final String __commandString[] = {
97 "IAC", "DONT", "DO", "WONT", "WILL", "SB", "GA", "EL", "EC", "AYT",
98 "AO", "IP", "BRK", "DMARK", "NOP", "SE", "EOR", "ABORT", "SUSP", "EOF"
99 };
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 }