    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
    018    package org.apache.commons.net;
    019    import 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     * <p>
    034     * <p>
    035     * @see ProtocolCommandEvent
    036     * @see ProtocolCommandSupport
    037     ***/
    038
    039    public 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         * <p>
    046         * @param event The ProtocolCommandEvent fired.
    047         ***/
    048        public void protocolCommandSent(ProtocolCommandEvent event);
    049
    050        /***
    051         * This method is invoked by a ProtocolCommandEvent source after
    052         * receiving a reply from a server.
    053         * <p>
    054         * @param event The ProtocolCommandEvent fired.
    055         ***/
    056        public void protocolReplyReceived(ProtocolCommandEvent event);
    057
    058    }