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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.hc.core5.http.nio;
29  
30  import java.io.IOException;
31  import java.nio.ByteBuffer;
32  import java.util.List;
33  
34  import org.apache.hc.core5.annotation.Contract;
35  import org.apache.hc.core5.annotation.ThreadingBehavior;
36  import org.apache.hc.core5.http.Header;
37  
38  /**
39   * Abstract byte stream channel
40   * <p>
41   * Implementations are expected to be thread-safe.
42   * </p>
43   *
44   * @since 5.0
45   */
46  @Contract(threading = ThreadingBehavior.SAFE)
47  public interface DataStreamChannel extends StreamChannel<ByteBuffer> {
48  
49      /**
50       * Signals intent by the data producer to produce more data.
51       * Once the channel is able to accept data its handler is expected
52       * to trigger an event to notify the data producer.
53       */
54      void requestOutput();
55  
56      /**
57       * Writes data from the buffer through this channel into the underlying byte stream.
58       * If the underlying byte stream is temporarily unable to accept more data
59       * it can return zero to indicate that no data could be written to the data
60       * stream. The data producer can choose to call {@link #requestOutput()}
61       * to signal its intent to produce more data.
62       *
63       * @param src source of data
64       *
65       * @return The number of bytes written, possibly zero
66       */
67      int write(ByteBuffer src) throws IOException;
68  
69      /**
70       * Terminates the underlying data stream and optionally writes
71       * a closing sequence with the given trailers.
72       * <p>
73       * Please note that some data streams may not support trailers
74       * and may silently ignore the trailers parameter.
75       * </p>
76       */
77      void endStream(List<? extends Header> trailers) throws IOException;
78  
79  }