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.protocol;
29
30 import java.io.Closeable;
31 import java.io.IOException;
32
33 import org.apache.http.HttpResponse;
34 import org.apache.http.nio.ContentEncoder;
35 import org.apache.http.nio.IOControl;
36 import org.apache.http.protocol.HttpContext;
37
38 /**
39 * {@code HttpAsyncResponseProducer} is a callback interface whose methods
40 * get invoked to generate an HTTP response message and to stream message
41 * content to a non-blocking HTTP connection on the server side.
42 *
43 * @since 4.2
44 */
45 public interface HttpAsyncResponseProducer extends Closeable {
46
47 /**
48 * Invoked to generate a HTTP response message head.
49 *
50 * @return HTTP response message.
51 */
52 HttpResponse generateResponse();
53
54 /**
55 * Invoked to write out a chunk of content to the {@link ContentEncoder}.
56 * The {@link IOControl} interface can be used to suspend output event
57 * notifications if the producer is temporarily unable to produce more content.
58 * <p>
59 * When all content is finished, the producer <b>MUST</b> call
60 * {@link ContentEncoder#complete()}. Failure to do so may cause the entity
61 * to be incorrectly delimited.
62 * <p>
63 * Please note that the {@link ContentEncoder} object is not thread-safe and
64 * should only be used within the context of this method call.
65 * The {@link IOControl} object can be shared and used on other thread
66 * to resume output event notifications when more content is made available.
67 *
68 * @param encoder content encoder.
69 * @param ioControl I/O control of the underlying connection.
70 * @throws IOException in case of an I/O error
71 */
72 void produceContent(ContentEncoder encoder, IOControl ioControl) throws IOException;
73
74 /**
75 * Invoked to signal that the response has been fully written out.
76 *
77 * @param context HTTP context
78 */
79 void responseCompleted(HttpContext context);
80
81 /**
82 * Invoked to signal that the response processing terminated abnormally.
83 *
84 * @param ex exception
85 */
86 void failed(Exception ex);
87
88 }