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 * 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 & 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) {
080            if (suboptionData[0] == TERMINAL_TYPE && suboptionData[1] == TERMINAL_TYPE_SEND) {
081                final int[] response = new int[termType.length() + 2];
082
083                response[0] = TERMINAL_TYPE;
084                response[1] = TERMINAL_TYPE_IS;
085
086                for (int ii = 0; ii < termType.length(); ii++) {
087                    response[ii + 2] = termType.charAt(ii);
088                }
089
090                return response;
091            }
092        }
093        return null;
094    }
095}