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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.Enumeration;
    19  import org.apache.commons.net.util.ListenerList;
    20
    21  /***
    22   * The CopyStreamAdapter will relay CopyStreamEvents to a list of listeners
    23   * when either of its bytesTransferred() methods are called.  Its purpose
    24   * is to facilitate the notification of the progress of a copy operation
    25   * performed by one of the static copyStream() methods in
    26   * org.apache.commons.io.Util to multiple listeners.  The static
    27   * copyStream() methods invoke the
    28   * bytesTransfered(long, int) of a CopyStreamListener for performance
    29   * reasons and also because multiple listeners cannot be registered given
    30   * that the methods are static.
    31   * <p>
    32   * <p>
    33   * @see CopyStreamEvent
    34   * @see CopyStreamListener
    35   * @see Util
    36   * @author <a href="mailto:savarese@apache.org">Daniel F. Savarese</a>
    37   * @version $Id: CopyStreamAdapter.java 165675 2005-05-02 20:09:55Z rwinston $
    38   */
    39  public class CopyStreamAdapter implements CopyStreamListener
    40  {
    41      private ListenerList internalListeners;
    42
    43      /***
    44       * Creates a new copyStreamAdapter.
    45       */
    46      public CopyStreamAdapter()
    47      {
    48          internalListeners = new ListenerList();
    49      }
    50
    51      /***
    52       * This method is invoked by a CopyStreamEvent source after copying
    53       * a block of bytes from a stream.  The CopyStreamEvent will contain
    54       * the total number of bytes transferred so far and the number of bytes
    55       * transferred in the last write.  The CopyStreamAdapater will relay
    56       * the event to all of its registered listeners, listing itself as the
    57       * source of the event.
    58       * @param event The CopyStreamEvent fired by the copying of a block of
    59       *              bytes.
    60       */
    61      public void bytesTransferred(CopyStreamEvent event)
    62      {
    63          bytesTransferred(event.getTotalBytesTransferred(),
    64                           event.getBytesTransferred(),
    65                           event.getStreamSize());
    66      }
    67
    68      /***
    69       * This method is not part of the JavaBeans model and is used by the
    70       * static methods in the org.apache.commons.io.Util class for efficiency.
    71       * It is invoked after a block of bytes to inform the listener of the
    72       * transfer.  The CopyStreamAdapater will create a CopyStreamEvent
    73       * from the arguments and relay the event to all of its registered
    74       * listeners, listing itself as the source of the event.
    75       * @param totalBytesTransferred  The total number of bytes transferred
    76       *         so far by the copy operation.
    77       * @param bytesTransferred  The number of bytes copied by the most recent
    78       *          write.
    79       * @param streamSize The number of bytes in the stream being copied.
    80       *        This may be equal to CopyStreamEvent.UNKNOWN_STREAM_SIZE if
    81       *        the size is unknown.
    82       */
    83      public void bytesTransferred(long totalBytesTransferred,
    84                                   int bytesTransferred, long streamSize)
    85      {
    86          Enumeration listeners;
    87          CopyStreamEvent event;
    88
    89          listeners = internalListeners.getListeners();
    90
    91          event = new CopyStreamEvent(this,
    92                                      totalBytesTransferred,
    93                                      bytesTransferred,
    94                                      streamSize);
    95
    96          while (listeners.hasMoreElements())
    97          {
    98              ((CopyStreamListener) (listeners.nextElement())).
    99                  bytesTransferred(event);
    100         }
    101     }
    102
    103     /***
    104      * Registers a CopyStreamListener to receive CopyStreamEvents.
    105      * Although this method is not declared to be synchronized, it is
    106      * implemented in a thread safe manner.
    107      * @param listener  The CopyStreamlistener to register.
    108      */
    109     public void addCopyStreamListener(CopyStreamListener listener)
    110     {
    111         internalListeners.addListener(listener);
    112     }
    113
    114     /***
    115      * Unregisters a CopyStreamListener.  Although this method is not
    116      * synchronized, it is implemented in a thread safe manner.
    117      * @param listener  The CopyStreamlistener to unregister.
    118      */
    119     public void removeCopyStreamListener(CopyStreamListener listener)
    120     {
    121         internalListeners.removeListener(listener);
    122     }
    123 }