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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   *   http://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing,
13   * software distributed under the License is distributed on an
14   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   * KIND, either express or implied.  See the License for the
16   * specific language governing permissions and limitations
17   * under the License.
18   */
19  package org.eclipse.aether.spi.connector.transport;
20  
21  import java.nio.ByteBuffer;
22  
23  import org.eclipse.aether.transfer.TransferCancelledException;
24  
25  /**
26   * A skeleton class for listeners used to monitor transport operations. Reusing common regular expression syntax, the
27   * sequence of events is generally as follows:
28   *
29   * <pre>
30   * ( STARTED PROGRESSED* )*
31   * </pre>
32   *
33   * The methods in this class do nothing.
34   */
35  public abstract class TransportListener {
36  
37      /**
38       * Enables subclassing.
39       */
40      protected TransportListener() {}
41  
42      /**
43       * Notifies the listener about the start of the data transfer. This event may arise more than once if the transfer
44       * needs to be restarted (e.g. after an authentication failure).
45       *
46       * @param dataOffset The byte offset in the resource at which the transfer starts, must not be negative.
47       * @param dataLength The total number of bytes in the resource or {@code -1} if the length is unknown.
48       * @throws TransferCancelledException If the transfer should be aborted.
49       */
50      public void transportStarted(long dataOffset, long dataLength) throws TransferCancelledException {}
51  
52      /**
53       * Notifies the listener about some progress in the data transfer. This event may even be fired if actually zero
54       * bytes have been transferred since the last event, for instance to enable cancellation.
55       *
56       * @param data The (read-only) buffer holding the bytes that have just been tranferred, must not be {@code null}.
57       * @throws TransferCancelledException If the transfer should be aborted.
58       */
59      public void transportProgressed(ByteBuffer data) throws TransferCancelledException {}
60  }