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1   /*
2    * Copyright 2009 Red Hat, Inc.
3    *
4    * Red Hat licenses this file to you under the Apache License, version 2.0
5    * (the "License"); you may not use this file except in compliance with the
6    * License.  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, WITHOUT
12   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
13   * License for the specific language governing permissions and limitations
14   * under the License.
15   */
16  package org.jboss.netty.channel;
17  
18  
19  /**
20   * Listens to the progress of a time-consuming I/O operation such as a large
21   * file transfer.  If this listener is added to a {@link ChannelFuture} of an
22   * I/O operation that supports progress notification, the listener's
23   * {@link #operationProgressed(ChannelFuture, long, long, long)} method will be
24   * called back by an I/O thread.  If the operation does not support progress
25   * notification, {@link #operationProgressed(ChannelFuture, long, long, long)}
26   * will not be invoked.  Like a usual {@link ChannelFutureListener} that this
27   * interface extends, {@link #operationComplete(ChannelFuture)} will be called
28   * when the future is marked as complete.
29   *
30   * <h3>Return the control to the caller quickly</h3>
31   *
32   * {@link #operationProgressed(ChannelFuture, long, long, long)} and
33   * {@link #operationComplete(ChannelFuture)} is directly called by an I/O
34   * thread.  Therefore, performing a time consuming task or a blocking operation
35   * in the handler method can cause an unexpected pause during I/O.  If you need
36   * to perform a blocking operation on I/O completion, try to execute the
37   * operation in a different thread using a thread pool.
38   *
39   * @author <a href="http://www.jboss.org/netty/">The Netty Project</a>
40   * @author <a href="http://gleamynode.net/">Trustin Lee</a>
41   *
42   * @version $Rev: 2080 $, $Date: 2010-01-26 18:04:19 +0900 (Tue, 26 Jan 2010) $
43   */
44  public interface ChannelFutureProgressListener extends ChannelFutureListener {
45  
46      /**
47       * Invoked when the I/O operation associated with the {@link ChannelFuture}
48       * has been progressed.
49       *
50       * @param future  the source {@link ChannelFuture} which called this
51       *                callback
52       */
53      void operationProgressed(ChannelFuture future, long amount, long current, long total) throws Exception;
54  }