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.io;
019
020import java.util.EventListener;
021
022import org.apache.commons.net.util.ListenerList;
023
024/**
025 * The CopyStreamAdapter will relay CopyStreamEvents to a list of listeners
026 * when either of its bytesTransferred() methods are called.  Its purpose
027 * is to facilitate the notification of the progress of a copy operation
028 * performed by one of the static copyStream() methods in
029 * org.apache.commons.io.Util to multiple listeners.  The static
030 * copyStream() methods invoke the
031 * bytesTransfered(long, int) of a CopyStreamListener for performance
032 * reasons and also because multiple listeners cannot be registered given
033 * that the methods are static.
034 *
035 *
036 * @see CopyStreamEvent
037 * @see CopyStreamListener
038 * @see Util
039 * @version $Id: CopyStreamAdapter.java 1741829 2016-05-01 00:24:44Z sebb $
040 */
041public class CopyStreamAdapter implements CopyStreamListener
042{
043    private final ListenerList internalListeners;
044
045    /**
046     * Creates a new copyStreamAdapter.
047     */
048    public CopyStreamAdapter()
049    {
050        internalListeners = new ListenerList();
051    }
052
053    /**
054     * This method is invoked by a CopyStreamEvent source after copying
055     * a block of bytes from a stream.  The CopyStreamEvent will contain
056     * the total number of bytes transferred so far and the number of bytes
057     * transferred in the last write.  The CopyStreamAdapater will relay
058     * the event to all of its registered listeners, listing itself as the
059     * source of the event.
060     * @param event The CopyStreamEvent fired by the copying of a block of
061     *              bytes.
062     */
063    @Override
064    public void bytesTransferred(CopyStreamEvent event)
065    {
066        for (EventListener listener : internalListeners)
067        {
068            ((CopyStreamListener) (listener)).bytesTransferred(event);
069        }
070    }
071
072    /**
073     * This method is not part of the JavaBeans model and is used by the
074     * static methods in the org.apache.commons.io.Util class for efficiency.
075     * It is invoked after a block of bytes to inform the listener of the
076     * transfer.  The CopyStreamAdapater will create a CopyStreamEvent
077     * from the arguments and relay the event to all of its registered
078     * listeners, listing itself as the source of the event.
079     * @param totalBytesTransferred  The total number of bytes transferred
080     *         so far by the copy operation.
081     * @param bytesTransferred  The number of bytes copied by the most recent
082     *          write.
083     * @param streamSize The number of bytes in the stream being copied.
084     *        This may be equal to CopyStreamEvent.UNKNOWN_STREAM_SIZE if
085     *        the size is unknown.
086     */
087    @Override
088    public void bytesTransferred(long totalBytesTransferred,
089                                 int bytesTransferred, long streamSize)
090    {
091        for (EventListener listener : internalListeners)
092        {
093            ((CopyStreamListener) (listener)).bytesTransferred(
094                    totalBytesTransferred, bytesTransferred, streamSize);
095        }
096    }
097
098    /**
099     * Registers a CopyStreamListener to receive CopyStreamEvents.
100     * Although this method is not declared to be synchronized, it is
101     * implemented in a thread safe manner.
102     * @param listener  The CopyStreamlistener to register.
103     */
104    public void addCopyStreamListener(CopyStreamListener listener)
105    {
106        internalListeners.addListener(listener);
107    }
108
109    /**
110     * Unregisters a CopyStreamListener.  Although this method is not
111     * synchronized, it is implemented in a thread safe manner.
112     * @param listener  The CopyStreamlistener to unregister.
113     */
114    public void removeCopyStreamListener(CopyStreamListener listener)
115    {
116        internalListeners.removeListener(listener);
117    }
118}