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 when either of its bytesTransferred() methods are called. Its purpose is to
26 * facilitate the notification of the progress of a copy operation performed by one of the static copyStream() methods in org.apache.commons.io.Util to multiple
27 * listeners. The static copyStream() methods invoke the bytesTransfered(long, int) of a CopyStreamListener for performance reasons and also because multiple
28 * listeners cannot be registered given that the methods are static.
29 *
30 *
31 * @see CopyStreamEvent
32 * @see CopyStreamListener
33 * @see Util
34 */
35 public class CopyStreamAdapter implements CopyStreamListener {
36 private final ListenerList internalListeners;
37
38 /**
39 * Creates a new copyStreamAdapter.
40 */
41 public CopyStreamAdapter() {
42 internalListeners = new ListenerList();
43 }
44
45 /**
46 * Registers a CopyStreamListener to receive CopyStreamEvents. Although this method is not declared to be synchronized, it is implemented in a thread safe
47 * manner.
48 *
49 * @param listener The CopyStreamlistener to register.
50 */
51 public void addCopyStreamListener(final CopyStreamListener listener) {
52 internalListeners.addListener(listener);
53 }
54
55 /**
56 * This method is invoked by a CopyStreamEvent source after copying a block of bytes from a stream. The CopyStreamEvent will contain the total number of
57 * bytes transferred so far and the number of bytes transferred in the last write. The CopyStreamAdapater will relay the event to all of its registered
58 * listeners, listing itself as the source of the event.
59 *
60 * @param event The CopyStreamEvent fired by the copying of a block of bytes.
61 */
62 @Override
63 public void bytesTransferred(final CopyStreamEvent event) {
64 for (final EventListener listener : internalListeners) {
65 ((CopyStreamListener) listener).bytesTransferred(event);
66 }
67 }
68
69 /**
70 * This method is not part of the JavaBeans model and is used by the static methods in the org.apache.commons.io.Util class for efficiency. It is invoked
71 * after a block of bytes to inform the listener of the transfer. The CopyStreamAdapater will create a CopyStreamEvent from the arguments and relay the
72 * event to all of its registered listeners, listing itself as the source of the event.
73 *
74 * @param totalBytesTransferred The total number of bytes transferred so far by the copy operation.
75 * @param bytesTransferred The number of bytes copied by the most recent write.
76 * @param streamSize The number of bytes in the stream being copied. This may be equal to CopyStreamEvent.UNKNOWN_STREAM_SIZE if the size is
77 * unknown.
78 */
79 @Override
80 public void bytesTransferred(final long totalBytesTransferred, final int bytesTransferred, final long streamSize) {
81 for (final EventListener listener : internalListeners) {
82 ((CopyStreamListener) listener).bytesTransferred(totalBytesTransferred, bytesTransferred, streamSize);
83 }
84 }
85
86 /**
87 * Unregisters a CopyStreamListener. Although this method is not synchronized, it is implemented in a thread safe manner.
88 *
89 * @param listener The CopyStreamlistener to unregister.
90 */
91 public void removeCopyStreamListener(final CopyStreamListener listener) {
92 internalListeners.removeListener(listener);
93 }
94 }