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1   /*
2    * ====================================================================
3    * Licensed to the Apache Software Foundation (ASF) under one
4    * or more contributor license agreements.  See the NOTICE file
5    * distributed with this work for additional information
6    * regarding copyright ownership.  The ASF licenses this file
7    * to you under the Apache License, Version 2.0 (the
8    * "License"); you may not use this file except in compliance
9    * with the License.  You may obtain a copy of the License at
10   *
11   *   http://www.apache.org/licenses/LICENSE-2.0
12   *
13   * Unless required by applicable law or agreed to in writing,
14   * software distributed under the License is distributed on an
15   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
16   * KIND, either express or implied.  See the License for the
17   * specific language governing permissions and limitations
18   * under the License.
19   * ====================================================================
20   *
21   * This software consists of voluntary contributions made by many
22   * individuals on behalf of the Apache Software Foundation.  For more
23   * information on the Apache Software Foundation, please see
24   * <http://www.apache.org/>.
25   *
26   */
27  
28  package org.apache.http.nio;
29  
30  import java.io.IOException;
31  import java.nio.channels.FileChannel;
32  
33  /**
34   * A content decoder capable of transferring data directly to a {@link FileChannel}
35   *
36   * @since 4.0
37   */
38  public interface FileContentDecoder extends ContentDecoder {
39  
40      /**
41       * Transfers a portion of entity content from the underlying network channel
42       * into the given file channel.<br>
43       *
44       * <b>Warning</b>: Many implementations cannot write beyond the length of the file.
45       *             If the position exceeds the channel's size, some implementations
46       *             may throw an IOException.
47       *
48       * @param  dst the target FileChannel to transfer data into.
49       * @param  position
50       *         The position within the file at which the transfer is to begin;
51       *         must be non-negative.
52       *         <b>Must be less than or equal to the size of the file</b>
53       * @param  count
54       *         The maximum number of bytes to be transferred; must be
55       *         non-negative
56       * @throws IOException if some I/O error occurs.
57       * @return  The number of bytes, possibly zero,
58       *          that were actually transferred
59       */
60      long transfer(FileChannel dst, long position, long count) throws IOException;
61  
62  }