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.HttpResponse;
34 import org.apache.http.concurrent.Cancellable;
35 import org.apache.http.nio.ContentDecoder;
36 import org.apache.http.nio.IOControl;
37 import org.apache.http.protocol.HttpContext;
38
39 /**
40 * {@code HttpAsyncResponseConsumer} is a callback interface whose methods
41 * get invoked to process an HTTP response message and to stream message
42 * content from a non-blocking HTTP connection on the client side.
43 *
44 * @param <T> the result type of response processing.
45 * @since 4.2
46 */
47 public interface HttpAsyncResponseConsumer<T> extends Closeable, Cancellable {
48
49 /**
50 * Invoked when a HTTP response message is received. Please note
51 * that the {@link #consumeContent(ContentDecoder, IOControl)} method
52 * will be invoked only if the response messages has a content entity
53 * enclosed.
54 *
55 * @param response HTTP response message.
56 * @throws HttpException in case of HTTP protocol violation
57 * @throws IOException in case of an I/O error
58 */
59 void responseReceived(HttpResponse response) throws IOException, HttpException;
60
61 /**
62 * Invoked to process a chunk of content from the {@link ContentDecoder}.
63 * The {@link IOControl} interface can be used to suspend input event
64 * notifications if the consumer is temporarily unable to process content.
65 * <p>
66 * The consumer can use the {@link ContentDecoder#isCompleted()} method
67 * to find out whether or not the message content has been fully consumed.
68 * <p>
69 * Please note that the {@link ContentDecoder} object is not thread-safe and
70 * should only be used within the context of this method call.
71 * The {@link IOControl} object can be shared and used on other thread
72 * to resume input event notifications when the consumer is capable of
73 * processing more content.
74 *
75 * @param decoder content decoder.
76 * @param ioControl I/O control of the underlying connection.
77 * @throws IOException in case of an I/O error
78 */
79 void consumeContent(ContentDecoder decoder, IOControl ioControl) throws IOException;
80
81 /**
82 * Invoked to signal that the response has been fully processed.
83 *
84 * @param context HTTP context
85 */
86 void responseCompleted(HttpContext context);
87
88 /**
89 * Invoked to signal that the response processing terminated abnormally.
90 *
91 * @param ex exception
92 */
93 void failed(Exception ex);
94
95 /**
96 * Returns an exception in case of an abnormal termination. This method
97 * returns {@code null} if the response processing is still ongoing
98 * or if it completed successfully.
99 *
100 * @see #isDone()
101 */
102 Exception getException();
103
104 /**
105 * Returns a result of the response processing, when available. This method
106 * returns {@code null} if the response processing is still ongoing.
107 *
108 * @see #isDone()
109 */
110 T getResult();
111
112 /**
113 * Determines whether or not the response processing completed. If the
114 * response processing terminated normally {@link #getResult()}
115 * can be used to obtain the result. If the response processing terminated
116 * abnormally {@link #getException()} can be used to obtain the cause.
117 */
118 boolean isDone();
119
120 }