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.io;
019
020 import java.util.EventListener;
021
022 import 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 * <p>
035 * <p>
036 * @see CopyStreamEvent
037 * @see CopyStreamListener
038 * @see Util
039 * @version $Id: CopyStreamAdapter.java 1299238 2012-03-10 17:12:28Z sebb $
040 */
041 public 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 public void bytesTransferred(CopyStreamEvent event)
064 {
065 for (EventListener listener : internalListeners)
066 {
067 ((CopyStreamListener) (listener)).bytesTransferred(event);
068 }
069 }
070
071 /**
072 * This method is not part of the JavaBeans model and is used by the
073 * static methods in the org.apache.commons.io.Util class for efficiency.
074 * It is invoked after a block of bytes to inform the listener of the
075 * transfer. The CopyStreamAdapater will create a CopyStreamEvent
076 * from the arguments and relay the event to all of its registered
077 * listeners, listing itself as the source of the event.
078 * @param totalBytesTransferred The total number of bytes transferred
079 * so far by the copy operation.
080 * @param bytesTransferred The number of bytes copied by the most recent
081 * write.
082 * @param streamSize The number of bytes in the stream being copied.
083 * This may be equal to CopyStreamEvent.UNKNOWN_STREAM_SIZE if
084 * the size is unknown.
085 */
086 public void bytesTransferred(long totalBytesTransferred,
087 int bytesTransferred, long streamSize)
088 {
089 for (EventListener listener : internalListeners)
090 {
091 ((CopyStreamListener) (listener)).bytesTransferred(
092 totalBytesTransferred, bytesTransferred, streamSize);
093 }
094 }
095
096 /**
097 * Registers a CopyStreamListener to receive CopyStreamEvents.
098 * Although this method is not declared to be synchronized, it is
099 * implemented in a thread safe manner.
100 * @param listener The CopyStreamlistener to register.
101 */
102 public void addCopyStreamListener(CopyStreamListener listener)
103 {
104 internalListeners.addListener(listener);
105 }
106
107 /**
108 * Unregisters a CopyStreamListener. Although this method is not
109 * synchronized, it is implemented in a thread safe manner.
110 * @param listener The CopyStreamlistener to unregister.
111 */
112 public void removeCopyStreamListener(CopyStreamListener listener)
113 {
114 internalListeners.removeListener(listener);
115 }
116 }