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 * The TelnetNotificationHandler interface can be used to handle notification of options negotiation commands received on a Telnet session.
022 * <p>
023 * The user can implement this interface and register a TelnetNotificationHandler by using the registerNotificationHandler() of TelnetClient to be notified of
024 * option negotiation commands.
025 * </p>
026 */
027public interface TelnetNotificationHandler {
028
029    /**
030     * The remote party sent a DO command.
031     */
032    int RECEIVED_DO = 1;
033
034    /**
035     * The remote party sent a {@code DONT} command.
036     */
037    int RECEIVED_DONT = 2;
038
039    /**
040     * The remote party sent a {@code WILL} command.
041     */
042    int RECEIVED_WILL = 3;
043
044    /**
045     * The remote party sent a {@code WONT} command.
046     */
047    int RECEIVED_WONT = 4;
048
049    /**
050     * The remote party sent a {@code COMMAND}.
051     *
052     * @since 2.2
053     */
054    int RECEIVED_COMMAND = 5;
055
056    /**
057     * Callback method called when TelnetClient receives a command or option negotiation command
058     *
059     * @param negotiation_code   type of (negotiation) command received (RECEIVED_DO, RECEIVED_DONT, RECEIVED_WILL, RECEIVED_WONT, RECEIVED_COMMAND)
060     * @param option_code        code of the option negotiated, or the command code itself (e.g. NOP).
061     */
062    void receivedNegotiation(int negotiation_code, int option_code);
063}