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1   /*
2    * Copyright 2001-2005 The Apache Software Foundation
3    *
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    *
8    *     http://www.apache.org/licenses/LICENSE-2.0
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   * See the License for the specific language governing permissions and
14   * limitations under the License.
15   */
16  package org.apache.commons.net.io;
17  
18  import java.util.EventListener;
19  
20  /**
21   * The CopyStreamListener class can accept CopyStreamEvents to keep track
22   * of the progress of a stream copying operation.  However, it is currently
23   * not used that way within NetComponents for performance reasons.  Rather
24   * the bytesTransferred(long, int) method is called directly rather than
25   * passing an event to bytesTransferred(CopyStreamEvent), saving the creation
26   * of a CopyStreamEvent instance.  Also, the only place where
27   * CopyStreamListener is currently used within NetComponents is in the
28   * static methods of the uninstantiable org.apache.commons.io.Util class, which
29   * would preclude the use of addCopyStreamListener and
30   * removeCopyStreamListener methods.  However, future additions may use the
31   * JavaBean event model, which is why the hooks have been included from the
32   * beginning.
33   * <p>
34   * <p>
35   * @see CopyStreamEvent
36   * @see CopyStreamAdapter
37   * @see Util
38   * @author <a href="mailto:savarese@apache.org">Daniel F. Savarese</a>
39   * @version $Id: CopyStreamListener.java 165675 2005-05-02 20:09:55Z rwinston $
40   */
41  public interface CopyStreamListener extends EventListener
42  {
43      /**
44       * This method is invoked by a CopyStreamEvent source after copying
45       * a block of bytes from a stream.  The CopyStreamEvent will contain
46       * the total number of bytes transferred so far and the number of bytes
47       * transferred in the last write.
48       * @param event The CopyStreamEvent fired by the copying of a block of
49       *              bytes.
50       */
51      public void bytesTransferred(CopyStreamEvent event);
52  
53  
54      /**
55       * This method is not part of the JavaBeans model and is used by the
56       * static methods in the org.apache.commons.io.Util class for efficiency.
57       * It is invoked after a block of bytes to inform the listener of the
58       * transfer.
59       * @param totalBytesTransferred  The total number of bytes transferred
60       *         so far by the copy operation.
61       * @param bytesTransferred  The number of bytes copied by the most recent
62       *          write.
63       * @param streamSize The number of bytes in the stream being copied.
64       *        This may be equal to CopyStreamEvent.UNKNOWN_STREAM_SIZE if
65       *        the size is unknown.
66       */
67      public void bytesTransferred(long totalBytesTransferred,
68                                   int bytesTransferred,
69                                   long streamSize);
70  }