content: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You under the Apache License, Version 2.0
   * (the "License"); you may not use this file except in compliance with
   * the License.  You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package org.apache.commons.net.telnet;
  
  /**
   * The TelnetCommand class cannot be instantiated and only serves as a
   * storehouse for telnet command constants.
   * @see org.apache.commons.net.telnet.Telnet
   * @see org.apache.commons.net.telnet.TelnetClient
   */
  
  public final class TelnetCommand
  {
      /*** The maximum value a command code can have.  This value is 255. ***/
      public static final int MAX_COMMAND_VALUE = 255;
  
      /*** Interpret As Command code.  Value is 255 according to RFC 854. ***/
      public static final int IAC = 255;
  
      /*** Don't use option code.  Value is 254 according to RFC 854. ***/
      public static final int DONT = 254;
  
      /*** Request to use option code.  Value is 253 according to RFC 854. ***/
      public static final int DO = 253;
  
      /*** Refuse to use option code.  Value is 252 according to RFC 854. ***/
      public static final int WONT = 252;
  
      /*** Agree to use option code.  Value is 251 according to RFC 854. ***/
      public static final int WILL = 251;
  
      /*** Start subnegotiation code.  Value is 250 according to RFC 854. ***/
      public static final int SB = 250;
  
      /*** Go Ahead code.  Value is 249 according to RFC 854. ***/
      public static final int GA = 249;
  
      /*** Erase Line code.  Value is 248 according to RFC 854. ***/
      public static final int EL = 248;
  
      /*** Erase Character code.  Value is 247 according to RFC 854. ***/
      public static final int EC = 247;
  
      /*** Are You There code.  Value is 246 according to RFC 854. ***/
      public static final int AYT = 246;
  
      /*** Abort Output code.  Value is 245 according to RFC 854. ***/
      public static final int AO = 245;
  
      /*** Interrupt Process code.  Value is 244 according to RFC 854. ***/
      public static final int IP = 244;
  
      /*** Break code.  Value is 243 according to RFC 854. ***/
      public static final int BREAK = 243;
  
      /*** Data mark code.  Value is 242 according to RFC 854. ***/
      public static final int DM = 242;
  
      /*** No Operation code.  Value is 241 according to RFC 854. ***/
      public static final int NOP = 241;
  
      /*** End subnegotiation code.  Value is 240 according to RFC 854. ***/
      public static final int SE = 240;
  
      /*** End of record code.  Value is 239. ***/
      public static final int EOR = 239;
  
      /*** Abort code.  Value is 238. ***/
      public static final int ABORT = 238;
  
      /*** Suspend process code.  Value is 237. ***/
      public static final int SUSP = 237;
  
      /*** End of file code.  Value is 236. ***/
      public static final int EOF = 236;
  
      /*** Synchronize code.  Value is 242. ***/
      public static final int SYNCH = 242;
  
      /*** String representations of commands. ***/
      private static final String __commandString[] = {
                  "IAC", "DONT", "DO", "WONT", "WILL", "SB", "GA", "EL", "EC", "AYT",
                  "AO", "IP", "BRK", "DMARK", "NOP", "SE", "EOR", "ABORT", "SUSP", "EOF"
              };
  
      private static final int __FIRST_COMMAND = IAC;
      private static final int __LAST_COMMAND = EOF;
  
      /***
       * Returns the string representation of the telnet protocol command
       * corresponding to the given command code.
       * <p>
       * @param code The command code of the telnet protocol command.
       * @return The string representation of the telnet protocol command.
       ***/
      public static final String getCommand(int code)
      {
          return __commandString[__FIRST_COMMAND - code];
      }
  
      /***
       * Determines if a given command code is valid.  Returns true if valid,
       * false if not.
       * <p>
       * @param code  The command code to test.
       * @return True if the command code is valid, false if not.
       **/
      public static final boolean isValidCommand(int code)
      {
          return (code <= __FIRST_COMMAND && code >= __LAST_COMMAND);
      }
  
      // Cannot be instantiated
      private TelnetCommand()
      { }
  }
  