1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18 package org.apache.commons.net.io;
19
20 import java.util.EventListener;
21
22 import org.apache.commons.net.util.ListenerList;
23
24 /**
25 * The CopyStreamAdapter will relay CopyStreamEvents to a list of listeners
26 * when either of its bytesTransferred() methods are called. Its purpose
27 * is to facilitate the notification of the progress of a copy operation
28 * performed by one of the static copyStream() methods in
29 * org.apache.commons.io.Util to multiple listeners. The static
30 * copyStream() methods invoke the
31 * bytesTransfered(long, int) of a CopyStreamListener for performance
32 * reasons and also because multiple listeners cannot be registered given
33 * that the methods are static.
34 * <p>
35 * <p>
36 * @see CopyStreamEvent
37 * @see CopyStreamListener
38 * @see Util
39 * @version $Id: CopyStreamAdapter.java 1417442 2012-12-05 14:32:02Z sebb $
40 */
41 public class CopyStreamAdapter implements CopyStreamListener
42 {
43 private final ListenerList internalListeners;
44
45 /**
46 * Creates a new copyStreamAdapter.
47 */
48 public CopyStreamAdapter()
49 {
50 internalListeners = new ListenerList();
51 }
52
53 /**
54 * This method is invoked by a CopyStreamEvent source after copying
55 * a block of bytes from a stream. The CopyStreamEvent will contain
56 * the total number of bytes transferred so far and the number of bytes
57 * transferred in the last write. The CopyStreamAdapater will relay
58 * the event to all of its registered listeners, listing itself as the
59 * source of the event.
60 * @param event The CopyStreamEvent fired by the copying of a block of
61 * bytes.
62 */
63 @Override
64 public void bytesTransferred(CopyStreamEvent event)
65 {
66 for (EventListener listener : internalListeners)
67 {
68 ((CopyStreamListener) (listener)).bytesTransferred(event);
69 }
70 }
71
72 /**
73 * This method is not part of the JavaBeans model and is used by the
74 * static methods in the org.apache.commons.io.Util class for efficiency.
75 * It is invoked after a block of bytes to inform the listener of the
76 * transfer. The CopyStreamAdapater will create a CopyStreamEvent
77 * from the arguments and relay the event to all of its registered
78 * listeners, listing itself as the source of the event.
79 * @param totalBytesTransferred The total number of bytes transferred
80 * so far by the copy operation.
81 * @param bytesTransferred The number of bytes copied by the most recent
82 * write.
83 * @param streamSize The number of bytes in the stream being copied.
84 * This may be equal to CopyStreamEvent.UNKNOWN_STREAM_SIZE if
85 * the size is unknown.
86 */
87 @Override
88 public void bytesTransferred(long totalBytesTransferred,
89 int bytesTransferred, long streamSize)
90 {
91 for (EventListener listener : internalListeners)
92 {
93 ((CopyStreamListener) (listener)).bytesTransferred(
94 totalBytesTransferred, bytesTransferred, streamSize);
95 }
96 }
97
98 /**
99 * 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 }