    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;
    019import java.util.EventListener;
    020
    021/**
    022 * There exists a large class of IETF protocols that work by sending an
    023 * ASCII text command and arguments to a server, and then receiving an
    024 * ASCII text reply.  For debugging and other purposes, it is extremely
    025 * useful to log or keep track of the contents of the protocol messages.
    026 * The ProtocolCommandListener interface coupled with the
    027 * {@link ProtocolCommandEvent} class facilitate this process.
    028 * <p>
    029 * To receive ProtocolCommandEvents, you merely implement the
    030 * ProtocolCommandListener interface and register the class as a listener
    031 * with a ProtocolCommandEvent source such as
    032 * {@link org.apache.commons.net.ftp.FTPClient}.
    033 *
    034 *
    035 * @see ProtocolCommandEvent
    036 * @see ProtocolCommandSupport
    037 */
    038
    039public interface ProtocolCommandListener extends EventListener
    040{
    041
    042    /**
    043     * This method is invoked by a ProtocolCommandEvent source after
    044     * sending a protocol command to a server.
    045     *
    046     * @param event The ProtocolCommandEvent fired.
    047     */
    048    void protocolCommandSent(ProtocolCommandEvent event);
    049
    050    /**
    051     * This method is invoked by a ProtocolCommandEvent source after
    052     * receiving a reply from a server.
    053     *
    054     * @param event The ProtocolCommandEvent fired.
    055     */
    056    void protocolReplyReceived(ProtocolCommandEvent event);
    057
    058}