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    /**
026     * Terminal type option
027     */
028    protected static final int TERMINAL_TYPE = 24;
029
030    /**
031     * Send (for subnegotiation)
032     */
033    protected static final int TERMINAL_TYPE_SEND = 1;
034
035    /**
036     * Is (for subnegotiation)
037     */
038    protected static final int TERMINAL_TYPE_IS = 0;
039
040    /**
041     * Terminal type
042     */
043    private final String termType;
044
045    /**
046     * Constructor for the TerminalTypeOptionHandler. Initial and accept behavior flags are set to false
047     *
048     * @param termtype   terminal type that will be negotiated.
049     */
050    public TerminalTypeOptionHandler(final String termtype) {
051        super(TelnetOption.TERMINAL_TYPE, false, false, false, false);
052        termType = termtype;
053    }
054
055    /**
056     * Constructor for the TerminalTypeOptionHandler. Allows defining desired initial setting for local/remote activation of this option and behavior in case a
057     * local/remote activation request for this option is received.
058     *
059     * @param termtype       terminal type that will be negotiated.
060     * @param initlocal      if set to true, a {@code WILL} is sent upon connection.
061     * @param initremote     if set to true, a {@code DO} is sent upon connection.
062     * @param acceptlocal    if set to true, any {@code DO} request is accepted.
063     * @param acceptremote   if set to true, any {@code WILL} request is accepted.
064     */
065    public TerminalTypeOptionHandler(final String termtype, final boolean initlocal, final boolean initremote, final boolean acceptlocal,
066            final boolean acceptremote) {
067        super(TelnetOption.TERMINAL_TYPE, initlocal, initremote, acceptlocal, acceptremote);
068        termType = termtype;
069    }
070
071    /**
072     * Implements the abstract method of TelnetOptionHandler.
073     *
074     * @param suboptionData     the sequence received, without IAC SB & IAC SE
075     * @param suboptionLength   the length of data in suboption_data
076     * @return terminal type information
077     */
078    @Override
079    public int[] answerSubnegotiation(final int suboptionData[], final int suboptionLength) {
080        if (suboptionData != null && suboptionLength > 1 && termType != null && suboptionData[0] == TERMINAL_TYPE && suboptionData[1] == TERMINAL_TYPE_SEND) {
081            final int[] response = new int[termType.length() + 2];
082            response[0] = TERMINAL_TYPE;
083            response[1] = TERMINAL_TYPE_IS;
084            for (int ii = 0; ii < termType.length(); ii++) {
085                response[ii + 2] = termType.charAt(ii);
086            }
087            return response;
088        }
089        return null;
090    }
091}