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 * @author <a href="mailto:savarese@apache.org">Daniel F. Savarese</a>
40 * @version $Id: CopyStreamAdapter.java 489397 2006-12-21 16:28:51Z rwinston $
41 */
42 public class CopyStreamAdapter implements CopyStreamListener
43 {
44 private ListenerList internalListeners;
45
46 /**
47 * Creates a new copyStreamAdapter.
48 */
49 public CopyStreamAdapter()
50 {
51 internalListeners = new ListenerList();
52 }
53
54 /**
55 * This method is invoked by a CopyStreamEvent source after copying
56 * a block of bytes from a stream. The CopyStreamEvent will contain
57 * the total number of bytes transferred so far and the number of bytes
58 * transferred in the last write. The CopyStreamAdapater will relay
59 * the event to all of its registered listeners, listing itself as the
60 * source of the event.
61 * @param event The CopyStreamEvent fired by the copying of a block of
62 * bytes.
63 */
64 public void bytesTransferred(CopyStreamEvent event)
65 {
66 bytesTransferred(event.getTotalBytesTransferred(),
67 event.getBytesTransferred(),
68 event.getStreamSize());
69 }
70
71 /**
72 * This method is not part of the JavaBeans model and is used by the
73 * static methods in the org.apache.commons.io.Util class for efficiency.
74 * It is invoked after a block of bytes to inform the listener of the
75 * transfer. The CopyStreamAdapater will create a CopyStreamEvent
76 * from the arguments and relay the event to all of its registered
77 * listeners, listing itself as the source of the event.
78 * @param totalBytesTransferred The total number of bytes transferred
79 * so far by the copy operation.
80 * @param bytesTransferred The number of bytes copied by the most recent
81 * write.
82 * @param streamSize The number of bytes in the stream being copied.
83 * This may be equal to CopyStreamEvent.UNKNOWN_STREAM_SIZE if
84 * the size is unknown.
85 */
86 public void bytesTransferred(long totalBytesTransferred,
87 int bytesTransferred, long streamSize)
88 {
89 CopyStreamEvent event;
90
91 event = new CopyStreamEvent(this,
92 totalBytesTransferred,
93 bytesTransferred,
94 streamSize);
95
96 for (EventListener listener : internalListeners)
97 {
98 ((CopyStreamListener) (listener)).bytesTransferred(event);
99 }
100 }
101
102 /**
103 * Registers a CopyStreamListener to receive CopyStreamEvents.
104 * Although this method is not declared to be synchronized, it is
105 * implemented in a thread safe manner.
106 * @param listener The CopyStreamlistener to register.
107 */
108 public void addCopyStreamListener(CopyStreamListener listener)
109 {
110 internalListeners.addListener(listener);
111 }
112
113 /**
114 * Unregisters a CopyStreamListener. Although this method is not
115 * synchronized, it is implemented in a thread safe manner.
116 * @param listener The CopyStreamlistener to unregister.
117 */
118 public void removeCopyStreamListener(CopyStreamListener listener)
119 {
120 internalListeners.removeListener(listener);
121 }
122 }