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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.entity;
29  
30  import java.io.Closeable;
31  import java.io.IOException;
32  
33  import org.apache.http.nio.ContentEncoder;
34  import org.apache.http.nio.IOControl;
35  
36  /**
37   * <tt>HttpAsyncContentProducer</tt> is a callback interface whose methods
38   * get invoked to stream out message content to a non-blocking HTTP connection.
39   *
40   * @since 4.2
41   */
42  public interface HttpAsyncContentProducer extends Closeable {
43  
44      /**
45       * Invoked to write out a chunk of content to the {@link ContentEncoder}.
46       * The {@link IOControl} interface can be used to suspend output event
47       * notifications if the entity is temporarily unable to produce more content.
48       * <p/>
49       * When all content is finished, the producer <b>MUST</b> call
50       * {@link ContentEncoder#complete()}. Failure to do so may cause the entity
51       * to be incorrectly delimited.
52       * <p/>
53       * Please note that the {@link ContentEncoder} object is not thread-safe and
54       * should only be used within the context of this method call.
55       * The {@link IOControl} object can be shared and used on other thread
56       * to resume output event notifications when more content is made available.
57       *
58       * @param encoder content encoder.
59       * @param ioctrl I/O control of the underlying connection.
60       */
61      void produceContent(ContentEncoder encoder, IOControl ioctrl) throws IOException;
62  
63      /**
64       * Determines whether or not this producer is capable of producing
65       * its content more than once. Repeatable content producers are expected
66       * to be able to recreate their content even after having been closed.
67       */
68      boolean isRepeatable();
69  
70  }