    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 *      https://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 * Implements the Telnet terminal type option RFC 1091.
    022 */
    023public class TerminalTypeOptionHandler extends TelnetOptionHandler {
    024    /**
    025     * Terminal type option
    026     */
    027    protected static final int TERMINAL_TYPE = 24;
    028
    029    /**
    030     * Send (for subnegotiation)
    031     */
    032    protected static final int TERMINAL_TYPE_SEND = 1;
    033
    034    /**
    035     * Is (for subnegotiation)
    036     */
    037    protected static final int TERMINAL_TYPE_IS = 0;
    038
    039    /**
    040     * Terminal type
    041     */
    042    private final String termType;
    043
    044    /**
    045     * Constructor for the TerminalTypeOptionHandler. Initial and accept behavior flags are set to false
    046     *
    047     * @param termtype   terminal type that will be negotiated.
    048     */
    049    public TerminalTypeOptionHandler(final String termtype) {
    050        super(TelnetOption.TERMINAL_TYPE, false, false, false, false);
    051        termType = termtype;
    052    }
    053
    054    /**
    055     * Constructor for the TerminalTypeOptionHandler. Allows defining desired initial setting for local/remote activation of this option and behavior in case a
    056     * local/remote activation request for this option is received.
    057     *
    058     * @param termtype       terminal type that will be negotiated.
    059     * @param initlocal      if set to true, a {@code WILL} is sent upon connection.
    060     * @param initremote     if set to true, a {@code DO} is sent upon connection.
    061     * @param acceptlocal    if set to true, any {@code DO} request is accepted.
    062     * @param acceptremote   if set to true, any {@code WILL} request is accepted.
    063     */
    064    public TerminalTypeOptionHandler(final String termtype, final boolean initlocal, final boolean initremote, final boolean acceptlocal,
    065            final boolean acceptremote) {
    066        super(TelnetOption.TERMINAL_TYPE, initlocal, initremote, acceptlocal, acceptremote);
    067        termType = termtype;
    068    }
    069
    070    /**
    071     * Implements the abstract method of TelnetOptionHandler.
    072     *
    073     * @param suboptionData     the sequence received, without IAC SB &amp; IAC SE
    074     * @param suboptionLength   the length of data in suboption_data
    075     * @return terminal type information
    076     */
    077    @Override
    078    public int[] answerSubnegotiation(final int suboptionData[], final int suboptionLength) {
    079        if (suboptionData != null && suboptionLength > 1 && termType != null && suboptionData[0] == TERMINAL_TYPE && suboptionData[1] == TERMINAL_TYPE_SEND) {
    080            final int[] response = new int[termType.length() + 2];
    081            response[0] = TERMINAL_TYPE;
    082            response[1] = TERMINAL_TYPE_IS;
    083            for (int ii = 0; ii < termType.length(); ii++) {
    084                response[ii + 2] = termType.charAt(ii);
    085            }
    086            return response;
    087        }
    088        return null;
    089    }
    090}