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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  /**
23   * The CopyStreamListener class can accept CopyStreamEvents to keep track
24   * of the progress of a stream copying operation.  However, it is currently
25   * not used that way within NetComponents for performance reasons.  Rather
26   * the bytesTransferred(long, int) method is called directly rather than
27   * passing an event to bytesTransferred(CopyStreamEvent), saving the creation
28   * of a CopyStreamEvent instance.  Also, the only place where
29   * CopyStreamListener is currently used within NetComponents is in the
30   * static methods of the uninstantiable org.apache.commons.io.Util class, which
31   * would preclude the use of addCopyStreamListener and
32   * removeCopyStreamListener methods.  However, future additions may use the
33   * JavaBean event model, which is why the hooks have been included from the
34   * beginning.
35   * <p>
36   * <p>
37   * @see CopyStreamEvent
38   * @see CopyStreamAdapter
39   * @see Util
40   * @version $Id: CopyStreamListener.java 1299238 2012-03-10 17:12:28Z sebb $
41   */
42  public interface CopyStreamListener extends EventListener
43  {
44      /**
45       * This method is invoked by a CopyStreamEvent source after copying
46       * a block of bytes from a stream.  The CopyStreamEvent will contain
47       * the total number of bytes transferred so far and the number of bytes
48       * transferred in the last write.
49       * @param event The CopyStreamEvent fired by the copying of a block of
50       *              bytes.
51       */
52      public void bytesTransferred(CopyStreamEvent event);
53  
54  
55      /**
56       * This method is not part of the JavaBeans model and is used by the
57       * static methods in the org.apache.commons.io.Util class for efficiency.
58       * It is invoked after a block of bytes to inform the listener of the
59       * transfer.
60       * @param totalBytesTransferred  The total number of bytes transferred
61       *         so far by the copy operation.
62       * @param bytesTransferred  The number of bytes copied by the most recent
63       *          write.
64       * @param streamSize The number of bytes in the stream being copied.
65       *        This may be equal to CopyStreamEvent.UNKNOWN_STREAM_SIZE if
66       *        the size is unknown.
67       */
68      public void bytesTransferred(long totalBytesTransferred,
69                                   int bytesTransferred,
70                                   long streamSize);
71  }