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 */
017package org.apache.commons.net;
018
019import java.io.ObjectInputStream;
020import java.io.ObjectOutputStream;
021import java.io.Serializable;
022
023import org.apache.commons.net.util.ListenerList;
024
025/**
026 * ProtocolCommandSupport is a convenience class for managing a list of ProtocolCommandListeners and firing ProtocolCommandEvents. You can simply delegate
027 * ProtocolCommandEvent firing and listener registering/unregistering tasks to this class.
028 *
029 * @see ProtocolCommandEvent
030 * @see ProtocolCommandListener
031 */
032public class ProtocolCommandSupport implements Serializable {
033
034    /**
035     * Serialization is unnecessary for this class. Reject attempts to do so until such time as the Serializable attribute can be dropped.
036     */
037    private static final long serialVersionUID = -8017692739988399978L;
038
039    /**
040     * The source to use for all generated ProtocolCommandEvents.
041     */
042    private final Object source;
043
044    /**
045     * The ProtocolCommandListener.
046     */
047    private final ListenerList<ProtocolCommandListener> listeners;
048
049    /**
050     * Creates a ProtocolCommandSupport instance using the indicated source as the source of ProtocolCommandEvents.
051     *
052     * @param source The source to use for all generated ProtocolCommandEvents.
053     */
054    public ProtocolCommandSupport(final Object source) {
055        this.listeners = new ListenerList<>();
056        this.source = source;
057    }
058
059    /**
060     * Adds a ProtocolCommandListener.
061     *
062     * @param listener The ProtocolCommandListener to add.
063     */
064    public void addProtocolCommandListener(final ProtocolCommandListener listener) {
065        listeners.addListener(listener);
066    }
067
068    /**
069     * Fires a ProtocolCommandEvent signaling the sending of a command to all registered listeners, invoking their
070     * {@link org.apache.commons.net.ProtocolCommandListener#protocolCommandSent protocolCommandSent()} methods.
071     *
072     * @param command The string representation of the command type sent, not including the arguments (e.g., "STAT" or "GET").
073     * @param message The entire command string verbatim as sent to the server, including all arguments.
074     */
075    public void fireCommandSent(final String command, final String message) {
076        if (!listeners.isEmpty()) {
077            final ProtocolCommandEvent event = new ProtocolCommandEvent(source, command, message);
078            listeners.forEach(listener -> listener.protocolCommandSent(event));
079        }
080    }
081
082    /**
083     * Fires a ProtocolCommandEvent signaling the reception of a command reply to all registered listeners, invoking their
084     * {@link org.apache.commons.net.ProtocolCommandListener#protocolReplyReceived protocolReplyReceived()} methods.
085     *
086     * @param replyCode The integer code indicating the nature of the reply. This will be the protocol integer value for protocols that use integer reply codes,
087     *                  or the reply class constant corresponding to the reply for protocols like POP3 that use strings like OK rather than integer codes (i.e.,
088     *                  POP3Repy.OK).
089     * @param message   The entire reply as received from the server.
090     */
091    public void fireReplyReceived(final int replyCode, final String message) {
092        if (!listeners.isEmpty()) {
093            final ProtocolCommandEvent event = new ProtocolCommandEvent(source, replyCode, message);
094            listeners.forEach(listener -> listener.protocolReplyReceived(event));
095        }
096    }
097
098    /**
099     * Gets the number of ProtocolCommandListeners currently registered.
100     *
101     * @return The number of ProtocolCommandListeners currently registered.
102     */
103    public int getListenerCount() {
104        return listeners.getListenerCount();
105    }
106
107    /**
108     * Throws UnsupportedOperationException.
109     *
110     * @param ignored Ignored.
111     */
112    private void readObject(final ObjectInputStream ignored) {
113        throw new UnsupportedOperationException("Serialization is not supported");
114    }
115
116    /**
117     * Removes a ProtocolCommandListener.
118     *
119     * @param listener The ProtocolCommandListener to remove.
120     */
121    public void removeProtocolCommandListener(final ProtocolCommandListener listener) {
122        listeners.removeListener(listener);
123    }
124
125    /**
126     * Always throws {@link UnsupportedOperationException}.
127     *
128     * @param ignored ignored.
129     * @throws UnsupportedOperationException Always thrown.
130     */
131    private void writeObject(final ObjectOutputStream ignored) {
132        throw new UnsupportedOperationException("Serialization is not supported");
133    }
134}