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 package org.apache.http.nio.protocol;
28
29 import java.io.Closeable;
30 import java.io.IOException;
31
32 import org.apache.http.HttpException;
33 import org.apache.http.HttpHost;
34 import org.apache.http.HttpRequest;
35 import org.apache.http.nio.ContentEncoder;
36 import org.apache.http.nio.IOControl;
37 import org.apache.http.protocol.HttpContext;
38
39 /**
40 * {@code HttpAsyncRequestProducer} is a callback interface whose methods
41 * get invoked to generate an HTTP request message and to stream message
42 * content to a non-blocking HTTP connection.
43 * <p>
44 * Repeatable request producers capable of generating the same request
45 * message more than once can be reset to their initial state by calling
46 * the {@link #resetRequest()} method, at which point request producers are
47 * expected to release currently allocated resources that are no longer needed
48 * or re-acquire resources needed to repeat the process.
49 *
50 * @since 4.2
51 */
52 public interface HttpAsyncRequestProducer extends Closeable {
53
54 /**
55 * Invoked to obtain the request target host.
56 */
57 HttpHost getTarget();
58
59 /**
60 * Invoked to generate a HTTP request message head. The message is expected
61 * to implement the {@link org.apache.http.HttpEntityEnclosingRequest} interface
62 * if it is to enclose a content entity. The {@link #produceContent(
63 * ContentEncoder, IOControl)} method will not be invoked if
64 * {@link org.apache.http.HttpEntityEnclosingRequest#getEntity()}
65 * returns {@code null}.
66 *
67 * @return HTTP request message.
68 * @throws HttpException in case of HTTP protocol violation
69 * @throws IOException in case of an I/O error
70 */
71 HttpRequest generateRequest() throws IOException, HttpException;
72
73 /**
74 * Invoked to write out a chunk of content to the {@link ContentEncoder}.
75 * The {@link IOControl} interface can be used to suspend output event
76 * notifications if the producer is temporarily unable to produce more content.
77 * <p>
78 * When all content is finished, the producer <b>MUST</b> call
79 * {@link ContentEncoder#complete()}. Failure to do so may cause the entity
80 * to be incorrectly delimited.
81 * <p>
82 * Please note that the {@link ContentEncoder} object is not thread-safe and
83 * should only be used within the context of this method call.
84 * The {@link IOControl} object can be shared and used on other thread
85 * to resume output event notifications when more content is made available.
86 *
87 * @param encoder content encoder.
88 * @param ioControl I/O control of the underlying connection.
89 * @throws IOException in case of an I/O error
90 */
91 void produceContent(ContentEncoder encoder, IOControl ioControl) throws IOException;
92
93 /**
94 * Invoked to signal that the request has been fully written out.
95 *
96 * @param context HTTP context
97 */
98 void requestCompleted(HttpContext context);
99
100 /**
101 * Invoked to signal that the response processing terminated abnormally.
102 *
103 * @param ex exception
104 */
105 void failed(Exception ex);
106
107 /**
108 * Determines whether or not this producer is capable of producing
109 * HTTP request messages more than once.
110 */
111 boolean isRepeatable();
112
113 /**
114 * Invoked to reset the producer to its initial state. Repeatable request
115 * producers are expected to release currently allocated resources that are
116 * no longer needed or re-acquire resources needed to repeat the process.
117 *
118 * @throws IOException in case of an I/O error
119 */
120 void resetRequest() throws IOException;
121
122 }