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 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     * The remote party sent a DO command.
030     */
031    int RECEIVED_DO = 1;
032
033    /**
034     * The remote party sent a {@code DONT} command.
035     */
036    int RECEIVED_DONT = 2;
037
038    /**
039     * The remote party sent a {@code WILL} command.
040     */
041    int RECEIVED_WILL = 3;
042
043    /**
044     * The remote party sent a {@code WONT} command.
045     */
046    int RECEIVED_WONT = 4;
047
048    /**
049     * The remote party sent a {@code COMMAND}.
050     *
051     * @since 2.2
052     */
053    int RECEIVED_COMMAND = 5;
054
055    /**
056     * Callback method called when TelnetClient receives a command or option negotiation command
057     *
058     * @param negotiation_code - type of (negotiation) command received (RECEIVED_DO, RECEIVED_DONT, RECEIVED_WILL, RECEIVED_WONT, RECEIVED_COMMAND)
059     *
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}