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.HttpException;
34 import org.apache.http.HttpResponse;
35 import org.apache.http.nio.ContentEncoder;
36 import org.apache.http.nio.IOControl;
37 import org.apache.http.protocol.HttpContext;
38
39 /**
40 * <tt>HttpAsyncResponseProducer</tt> is a callback interface whose methods
41 * get invoked to generate an HTTP response message and to stream message
42 * content to a non-blocking HTTP connection on the server side.
43 *
44 * @since 4.2
45 */
46 public interface HttpAsyncResponseProducer extends Closeable {
47
48 /**
49 * Invoked to generate a HTTP response message head.
50 *
51 * @return HTTP response message.
52 * @throws HttpException in case of HTTP protocol violation
53 * @throws IOException in case of an I/O error
54 */
55 HttpResponse generateResponse();
56
57 /**
58 * Invoked to write out a chunk of content to the {@link ContentEncoder}.
59 * The {@link IOControl} interface can be used to suspend output event
60 * notifications if the producer is temporarily unable to produce more content.
61 * <p/>
62 * When all content is finished, the producer <b>MUST</b> call
63 * {@link ContentEncoder#complete()}. Failure to do so may cause the entity
64 * to be incorrectly delimited.
65 * <p/>
66 * Please note that the {@link ContentEncoder} object is not thread-safe and
67 * should only be used within the context of this method call.
68 * The {@link IOControl} object can be shared and used on other thread
69 * to resume output event notifications when more content is made available.
70 *
71 * @param encoder content encoder.
72 * @param ioctrl I/O control of the underlying connection.
73 * @throws IOException in case of an I/O error
74 */
75 void produceContent(ContentEncoder encoder, IOControl ioctrl) throws IOException;
76
77 /**
78 * Invoked to signal that the response has been fully written out.
79 *
80 * @param context HTTP context
81 */
82 void responseCompleted(HttpContext context);
83
84 /**
85 * Invoked to signal that the response processing terminated abnormally.
86 *
87 * @param ex exception
88 */
89 void failed(Exception ex);
90
91 }