    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
    018package org.apache.commons.net.telnet;
    019
    020/**
    021 * The TelnetOptionHandler class is the base class to be used
    022 * for implementing handlers for telnet options.
    023 * <p>
    024 * TelnetOptionHandler implements basic option handling
    025 * functionality and defines abstract methods that must be
    026 * implemented to define subnegotiation behavior.
    027 */
    028public abstract class TelnetOptionHandler
    029{
    030    /**
    031     * Option code
    032     */
    033    private int optionCode = -1;
    034
    035    /**
    036     * true if the option should be activated on the local side
    037     */
    038    private boolean initialLocal;
    039
    040    /**
    041     * true if the option should be activated on the remote side
    042     */
    043    private boolean initialRemote;
    044
    045    /**
    046     * true if the option should be accepted on the local side
    047     */
    048    private boolean acceptLocal;
    049
    050    /**
    051     * true if the option should be accepted on the remote side
    052     */
    053    private boolean acceptRemote;
    054
    055    /**
    056     * true if the option is active on the local side
    057     */
    058    private boolean doFlag;
    059
    060    /**
    061     * true if the option is active on the remote side
    062     */
    063    private boolean willFlag;
    064
    065    /**
    066     * Constructor for the TelnetOptionHandler. Allows defining desired
    067     * initial setting for local/remote activation of this option and
    068     * behavior in case a local/remote activation request for this
    069     * option is received.
    070     * <p>
    071     * @param optcode - Option code.
    072     * @param initlocal - if set to true, a WILL is sent upon connection.
    073     * @param initremote - if set to true, a DO is sent upon connection.
    074     * @param acceptlocal - if set to true, any DO request is accepted.
    075     * @param acceptremote - if set to true, any WILL request is accepted.
    076     */
    077    public TelnetOptionHandler(final int optcode,
    078                                final boolean initlocal,
    079                                final boolean initremote,
    080                                final boolean acceptlocal,
    081                                final boolean acceptremote)
    082    {
    083        optionCode = optcode;
    084        initialLocal = initlocal;
    085        initialRemote = initremote;
    086        acceptLocal = acceptlocal;
    087        acceptRemote = acceptremote;
    088    }
    089
    090
    091    /**
    092     * Returns the option code for this option.
    093     * <p>
    094     * @return Option code.
    095     */
    096    public int getOptionCode()
    097    {
    098        return optionCode;
    099    }
    100
    101    /**
    102     * Returns a boolean indicating whether to accept a DO
    103     * request coming from the other end.
    104     * <p>
    105     * @return true if a DO request shall be accepted.
    106     */
    107    public boolean getAcceptLocal()
    108    {
    109        return acceptLocal;
    110    }
    111
    112    /**
    113     * Returns a boolean indicating whether to accept a WILL
    114     * request coming from the other end.
    115     * <p>
    116     * @return true if a WILL request shall be accepted.
    117     */
    118    public boolean getAcceptRemote()
    119    {
    120        return acceptRemote;
    121    }
    122
    123    /**
    124     * Set behavior of the option for DO requests coming from
    125     * the other end.
    126     * <p>
    127     * @param accept - if true, subsequent DO requests will be accepted.
    128     */
    129    public void setAcceptLocal(final boolean accept)
    130    {
    131        acceptLocal = accept;
    132    }
    133
    134    /**
    135     * Set behavior of the option for WILL requests coming from
    136     * the other end.
    137     * <p>
    138     * @param accept - if true, subsequent WILL requests will be accepted.
    139     */
    140    public void setAcceptRemote(final boolean accept)
    141    {
    142        acceptRemote = accept;
    143    }
    144
    145    /**
    146     * Returns a boolean indicating whether to send a WILL request
    147     * to the other end upon connection.
    148     * <p>
    149     * @return true if a WILL request shall be sent upon connection.
    150     */
    151    public boolean getInitLocal()
    152    {
    153        return initialLocal;
    154    }
    155
    156    /**
    157     * Returns a boolean indicating whether to send a DO request
    158     * to the other end upon connection.
    159     * <p>
    160     * @return true if a DO request shall be sent upon connection.
    161     */
    162    public boolean getInitRemote()
    163    {
    164        return initialRemote;
    165    }
    166
    167    /**
    168     * Tells this option whether to send a WILL request upon connection.
    169     * <p>
    170     * @param init - if true, a WILL request will be sent upon subsequent
    171     * connections.
    172     */
    173    public void setInitLocal(final boolean init)
    174    {
    175        initialLocal = init;
    176    }
    177
    178    /**
    179     * Tells this option whether to send a DO request upon connection.
    180     * <p>
    181     * @param init - if true, a DO request will be sent upon subsequent
    182     * connections.
    183     */
    184    public void setInitRemote(final boolean init)
    185    {
    186        initialRemote = init;
    187    }
    188
    189    /**
    190     * Method called upon reception of a subnegotiation for this option
    191     * coming from the other end.
    192     * <p>
    193     * This implementation returns null, and
    194     * must be overridden by the actual TelnetOptionHandler to specify
    195     * which response must be sent for the subnegotiation request.
    196     * <p>
    197     * @param suboptionData - the sequence received, without IAC SB &amp; IAC SE
    198     * @param suboptionLength - the length of data in suboption_data
    199     * <p>
    200     * @return response to be sent to the subnegotiation sequence. TelnetClient
    201     * will add IAC SB &amp; IAC SE. null means no response
    202     */
    203    public int[] answerSubnegotiation(final int suboptionData[], final int suboptionLength) {
    204        return null;
    205    }
    206
    207    /**
    208     * This method is invoked whenever this option is acknowledged active on
    209     * the local end (TelnetClient sent a WILL, remote side sent a DO).
    210     * The method is used to specify a subnegotiation sequence that will be
    211     * sent by TelnetClient when the option is activated.
    212     * <p>
    213     * This implementation returns null, and must be overriden by
    214     * the actual TelnetOptionHandler to specify
    215     * which response must be sent for the subnegotiation request.
    216     * @return subnegotiation sequence to be sent by TelnetClient. TelnetClient
    217     * will add IAC SB &amp; IAC SE. null means no subnegotiation.
    218     */
    219    public int[] startSubnegotiationLocal() {
    220        return null;
    221    }
    222
    223    /**
    224     * This method is invoked whenever this option is acknowledged active on
    225     * the remote end (TelnetClient sent a DO, remote side sent a WILL).
    226     * The method is used to specify a subnegotiation sequence that will be
    227     * sent by TelnetClient when the option is activated.
    228     * <p>
    229     * This implementation returns null, and must be overriden by
    230     * the actual TelnetOptionHandler to specify
    231     * which response must be sent for the subnegotiation request.
    232     * @return subnegotiation sequence to be sent by TelnetClient. TelnetClient
    233     * will add IAC SB &amp; IAC SE. null means no subnegotiation.
    234     */
    235    public int[] startSubnegotiationRemote() {
    236        return null;
    237    }
    238
    239    /**
    240     * Returns a boolean indicating whether a WILL request sent to the other
    241     * side has been acknowledged.
    242     * <p>
    243     * @return true if a WILL sent to the other side has been acknowledged.
    244     */
    245    boolean getWill()
    246    {
    247        return willFlag;
    248    }
    249
    250    /**
    251     * Tells this option whether a WILL request sent to the other
    252     * side has been acknowledged (invoked by TelnetClient).
    253     * <p>
    254     * @param state - if true, a WILL request has been acknowledged.
    255     */
    256    void setWill(final boolean state)
    257    {
    258        willFlag = state;
    259    }
    260
    261    /**
    262     * Returns a boolean indicating whether a DO request sent to the other
    263     * side has been acknowledged.
    264     * <p>
    265     * @return true if a DO sent to the other side has been acknowledged.
    266     */
    267    boolean getDo()
    268    {
    269        return doFlag;
    270    }
    271
    272
    273    /**
    274     * Tells this option whether a DO request sent to the other
    275     * side has been acknowledged (invoked by TelnetClient).
    276     * <p>
    277     * @param state - if true, a DO request has been acknowledged.
    278     */
    279    void setDo(final boolean state)
    280    {
    281        doFlag = state;
    282    }
    283}