/*
 * 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 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.
/***
 * The TelnetOptionHandler class is the base class to be used
 * for implementing handlers for telnet options.
 * <p>
 * TelnetOptionHandler implements basic option handling
 * functionality and defines abstract methods that must be
 * implemented to define subnegotiation behaviour.
 ***/
public abstract class TelnetOptionHandler
{
    
Option code
/***
     * Option code
     ***/
    private int optionCode = -1;

    
true if the option should be activated on the local side
/***
     * true if the option should be activated on the local side
     ***/
    private boolean initialLocal = false;

    
true if the option should be activated on the remote side
/***
     * true if the option should be activated on the remote side
     ***/
    private boolean initialRemote = false;

    
true if the option should be accepted on the local side
/***
     * true if the option should be accepted on the local side
     ***/
    private boolean acceptLocal = false;

    
true if the option should be accepted on the remote side
/***
     * true if the option should be accepted on the remote side
     ***/
    private boolean acceptRemote = false;

    
true if the option is active on the local side
/***
     * true if the option is active on the local side
     ***/
    private boolean doFlag = false;

    
true if the option is active on the remote side
/***
     * true if the option is active on the remote side
     ***/
    private boolean willFlag = false;

    
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.

Params:
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./***
     * 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.
     * <p>
     * @param optcode - Option code.
     * @param initlocal - if set to true, a WILL is sent upon connection.
     * @param initremote - if set to true, a DO is sent upon connection.
     * @param acceptlocal - if set to true, any DO request is accepted.
     * @param acceptremote - if set to true, any WILL request is accepted.
     ***/
    public TelnetOptionHandler(int optcode,
                                boolean initlocal,
                                boolean initremote,
                                boolean acceptlocal,
                                boolean acceptremote)
    {
        optionCode = optcode;
        initialLocal = initlocal;
        initialRemote = initremote;
        acceptLocal = acceptlocal;
        acceptRemote = acceptremote;
    }


    
Returns the option code for this option.

Returns:
Option code./***
     * Returns the option code for this option.
     * <p>
     * @return Option code.
     ***/
    public int getOptionCode()
    {
        return (optionCode);
    }

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

Returns:
true if a DO request shall be accepted./***
     * Returns a boolean indicating whether to accept a DO
     * request coming from the other end.
     * <p>
     * @return true if a DO request shall be accepted.
     ***/
    public boolean getAcceptLocal()
    {
        return (acceptLocal);
    }

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

Returns:
true if a WILL request shall be accepted./***
     * Returns a boolean indicating whether to accept a WILL
     * request coming from the other end.
     * <p>
     * @return true if a WILL request shall be accepted.
     ***/
    public boolean getAcceptRemote()
    {
        return (acceptRemote);
    }

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

Params:
accept – - if true, subsequent DO requests will be accepted./***
     * Set behaviour of the option for DO requests coming from
     * the other end.
     * <p>
     * @param accept - if true, subsequent DO requests will be accepted.
     ***/
    public void setAcceptLocal(boolean accept)
    {
        acceptLocal = accept;
    }

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

Params:
accept – - if true, subsequent WILL requests will be accepted./***
     * Set behaviour of the option for WILL requests coming from
     * the other end.
     * <p>
     * @param accept - if true, subsequent WILL requests will be accepted.
     ***/
    public void setAcceptRemote(boolean accept)
    {
        acceptRemote = accept;
    }

    
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./***
     * Returns a boolean indicating whether to send a WILL request
     * to the other end upon connection.
     * <p>
     * @return true if a WILL request shall be sent upon connection.
     ***/
    public boolean getInitLocal()
    {
        return (initialLocal);
    }

    
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./***
     * Returns a boolean indicating whether to send a DO request
     * to the other end upon connection.
     * <p>
     * @return true if a DO request shall be sent upon connection.
     ***/
    public boolean getInitRemote()
    {
        return (initialRemote);
    }

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

Params:
init – - if true, a WILL request will be sent upon subsequent
connections./***
     * Tells this option whether to send a WILL request upon connection.
     * <p>
     * @param init - if true, a WILL request will be sent upon subsequent
     * connections.
     ***/
    public void setInitLocal(boolean init)
    {
        initialLocal = init;
    }

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

Params:
init – - if true, a DO request will be sent upon subsequent
connections./***
     * Tells this option whether to send a DO request upon connection.
     * <p>
     * @param init - if true, a DO request will be sent upon subsequent
     * connections.
     ***/
    public void setInitRemote(boolean init)
    {
        initialRemote = init;
    }

    
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.

Params:
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/***
     * Method called upon reception of a subnegotiation for this option
     * coming from the other end.
     * <p>
     * This implementation returns null, and
     * must be overridden by the actual TelnetOptionHandler to specify
     * which response must be sent for the subnegotiation request.
     * <p>
     * @param suboptionData - the sequence received, without IAC SB &amp; IAC SE
     * @param suboptionLength - the length of data in suboption_data
     * <p>
     * @return response to be sent to the subnegotiation sequence. TelnetClient
     * will add IAC SB &amp; IAC SE. null means no response
     ***/
    public int[] answerSubnegotiation(int suboptionData[], int suboptionLength) {
        return null;
    }

    
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./***
     * 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.
     * <p>
     * This implementation returns null, and must be overriden by
     * the actual TelnetOptionHandler to specify
     * which response must be sent for the subnegotiation request.
     * @return subnegotiation sequence to be sent by TelnetClient. TelnetClient
     * will add IAC SB &amp; IAC SE. null means no subnegotiation.
     ***/
    public int[] startSubnegotiationLocal() {
        return null;
    }

    
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./***
     * 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.
     * <p>
     * This implementation returns null, and must be overriden by
     * the actual TelnetOptionHandler to specify
     * which response must be sent for the subnegotiation request.
     * @return subnegotiation sequence to be sent by TelnetClient. TelnetClient
     * will add IAC SB &amp; IAC SE. null means no subnegotiation.
     ***/
    public int[] startSubnegotiationRemote() {
        return null;
    }

    
Returns a boolean indicating whether a WILL request sent to the other
side has been acknowledged.

Returns:
true if a WILL sent to the other side has been acknowledged./***
     * Returns a boolean indicating whether a WILL request sent to the other
     * side has been acknowledged.
     * <p>
     * @return true if a WILL sent to the other side has been acknowledged.
     ***/
    boolean getWill()
    {
        return willFlag;
    }

    
Tells this option whether a WILL request sent to the other
side has been acknowledged (invoked by TelnetClient).

Params:
state – - if true, a WILL request has been acknowledged./***
     * Tells this option whether a WILL request sent to the other
     * side has been acknowledged (invoked by TelnetClient).
     * <p>
     * @param state - if true, a WILL request has been acknowledged.
     ***/
    void setWill(boolean state)
    {
        willFlag = state;
    }

    
Returns a boolean indicating whether a DO request sent to the other
side has been acknowledged.

Returns:
true if a DO sent to the other side has been acknowledged./***
     * Returns a boolean indicating whether a DO request sent to the other
     * side has been acknowledged.
     * <p>
     * @return true if a DO sent to the other side has been acknowledged.
     ***/
    boolean getDo()
    {
        return doFlag;
    }


    
Tells this option whether a DO request sent to the other
side has been acknowledged (invoked by TelnetClient).

Params:
state – - if true, a DO request has been acknowledged./***
     * Tells this option whether a DO request sent to the other
     * side has been acknowledged (invoked by TelnetClient).
     * <p>
     * @param state - if true, a DO request has been acknowledged.
     ***/
    void setDo(boolean state)
    {
        doFlag = state;
    }
}