TelnetOptionHandler
Date: 2016-06-23

org.apache.commons.net.telnet

## Class TelnetOptionHandler

- java.lang.Object
- - org.apache.commons.net.telnet.TelnetOptionHandler

- Direct Known Subclasses:
    EchoOptionHandler, SimpleOptionHandler, SuppressGAOptionHandler, TerminalTypeOptionHandler, WindowSizeOptionHandler

      public abstract class TelnetOptionHandler
      extends java.lang.Object

  The TelnetOptionHandler class is the base class to be used for implementing handlers for telnet options.

  TelnetOptionHandler implements basic option handling functionality and defines abstract methods that must be implemented to define subnegotiation behaviour.

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `TelnetOptionHandler(int optcode, boolean initlocal, boolean initremote, boolean acceptlocal, boolean acceptremote)` Constructor for the TelnetOptionHandler.

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `int[]` | `answerSubnegotiation(int[] suboptionData, int suboptionLength)` Method called upon reception of a subnegotiation for this option coming from the other end.
    `boolean` | `getAcceptLocal()` Returns a boolean indicating whether to accept a DO request coming from the other end.
    `boolean` | `getAcceptRemote()` Returns a boolean indicating whether to accept a WILL request coming from the other end.
    `boolean` | `getInitLocal()` Returns a boolean indicating whether to send a WILL request to the other end upon connection.
    `boolean` | `getInitRemote()` Returns a boolean indicating whether to send a DO request to the other end upon connection.
    `int` | `getOptionCode()` Returns the option code for this option.
    `void` | `setAcceptLocal(boolean accept)` Set behaviour of the option for DO requests coming from the other end.
    `void` | `setAcceptRemote(boolean accept)` Set behaviour of the option for WILL requests coming from the other end.
    `void` | `setInitLocal(boolean init)` Tells this option whether to send a WILL request upon connection.
    `void` | `setInitRemote(boolean init)` Tells this option whether to send a DO request upon connection.
    `int[]` | `startSubnegotiationLocal()` This method is invoked whenever this option is acknowledged active on the local end (TelnetClient sent a WILL, remote side sent a DO).
    `int[]` | `startSubnegotiationRemote()` This method is invoked whenever this option is acknowledged active on the remote end (TelnetClient sent a DO, remote side sent a WILL).

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- - ### Constructor Detail

    - #### TelnetOptionHandler

          public TelnetOptionHandler(int optcode,
                             boolean initlocal,
                             boolean initremote,
                             boolean acceptlocal,
                             boolean acceptremote)

      Constructor for the TelnetOptionHandler. Allows defining desired initial setting for local/remote activation of this option and behaviour in case a local/remote activation request for this option is received.

      Parameters:
        `optcode` - - Option code.
        `initlocal` - - if set to true, a WILL is sent upon connection.
        `initremote` - - if set to true, a DO is sent upon connection.
        `acceptlocal` - - if set to true, any DO request is accepted.
        `acceptremote` - - if set to true, any WILL request is accepted.

  - ### Method Detail

    - #### getOptionCode

          public int getOptionCode()

      Returns the option code for this option.

      Returns:
        Option code.

    - #### getAcceptLocal

          public boolean getAcceptLocal()

      Returns a boolean indicating whether to accept a DO request coming from the other end.

      Returns:
        true if a DO request shall be accepted.

    - #### getAcceptRemote

          public boolean getAcceptRemote()

      Returns a boolean indicating whether to accept a WILL request coming from the other end.

      Returns:
        true if a WILL request shall be accepted.

    - #### setAcceptLocal

          public void setAcceptLocal(boolean accept)

      Set behaviour of the option for DO requests coming from the other end.

      Parameters:
        `accept` - - if true, subsequent DO requests will be accepted.

    - #### setAcceptRemote

          public void setAcceptRemote(boolean accept)

      Set behaviour of the option for WILL requests coming from the other end.

      Parameters:
        `accept` - - if true, subsequent WILL requests will be accepted.

    - #### getInitLocal

          public boolean getInitLocal()

      Returns a boolean indicating whether to send a WILL request to the other end upon connection.

      Returns:
        true if a WILL request shall be sent upon connection.

    - #### getInitRemote

          public boolean getInitRemote()

      Returns a boolean indicating whether to send a DO request to the other end upon connection.

      Returns:
        true if a DO request shall be sent upon connection.

    - #### setInitLocal

          public void setInitLocal(boolean init)

      Tells this option whether to send a WILL request upon connection.

      Parameters:
        `init` - - if true, a WILL request will be sent upon subsequent connections.

    - #### setInitRemote

          public void setInitRemote(boolean init)

      Tells this option whether to send a DO request upon connection.

      Parameters:
        `init` - - if true, a DO request will be sent upon subsequent connections.

    - #### answerSubnegotiation

          public int[] answerSubnegotiation(int[] suboptionData,
                                   int suboptionLength)

      Method called upon reception of a subnegotiation for this option coming from the other end.

      This implementation returns null, and must be overridden by the actual TelnetOptionHandler to specify which response must be sent for the subnegotiation request.

      Parameters:
        `suboptionData` - - the sequence received, without IAC SB & IAC SE
        `suboptionLength` - - the length of data in suboption_data

      Returns:
        response to be sent to the subnegotiation sequence. TelnetClient will add IAC SB & IAC SE. null means no response

    - #### startSubnegotiationLocal

          public int[] startSubnegotiationLocal()

      This method is invoked whenever this option is acknowledged active on the local end (TelnetClient sent a WILL, remote side sent a DO). The method is used to specify a subnegotiation sequence that will be sent by TelnetClient when the option is activated.

      This implementation returns null, and must be overriden by the actual TelnetOptionHandler to specify which response must be sent for the subnegotiation request.

      Returns:
        subnegotiation sequence to be sent by TelnetClient. TelnetClient will add IAC SB & IAC SE. null means no subnegotiation.

    - #### startSubnegotiationRemote

          public int[] startSubnegotiationRemote()

      This method is invoked whenever this option is acknowledged active on the remote end (TelnetClient sent a DO, remote side sent a WILL). The method is used to specify a subnegotiation sequence that will be sent by TelnetClient when the option is activated.

      This implementation returns null, and must be overriden by the actual TelnetOptionHandler to specify which response must be sent for the subnegotiation request.

      Returns:
        subnegotiation sequence to be sent by TelnetClient. TelnetClient will add IAC SB & IAC SE. null means no subnegotiation.