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;
29
30 import java.io.IOException;
31
32 import org.apache.http.HttpException;
33
34 /**
35 * Abstract client-side HTTP protocol handler.
36 *
37 * @since 4.2
38 */
39 public interface NHttpClientEventHandler {
40
41 /**
42 * Triggered when a new outgoing connection is created.
43 *
44 * @param conn new outgoing HTTP connection.
45 * @param attachment an object that was attached to the session request
46 */
47 void connected(
48 NHttpClientConnection conn,
49 Object attachment) throws IOException, HttpException;
50
51 /**
52 * Triggered when the connection is ready to accept a new HTTP request.
53 * The protocol handler does not have to submit a request if it is not
54 * ready.
55 *
56 * @see NHttpClientConnection
57 *
58 * @param conn HTTP connection that is ready to accept a new HTTP request.
59 */
60 void requestReady(
61 NHttpClientConnection conn) throws IOException, HttpException;
62
63 /**
64 * Triggered when an HTTP response is received. The connection
65 * passed as a parameter to this method is guaranteed to return
66 * a valid HTTP response object.
67 * <p>
68 * If the response received encloses a response entity this method will
69 * be followed by a series of
70 * {@link #inputReady(NHttpClientConnection, ContentDecoder)} calls
71 * to transfer the response content.
72 *
73 * @see NHttpClientConnection
74 *
75 * @param conn HTTP connection that contains an HTTP response
76 */
77 void responseReceived(
78 NHttpClientConnection conn) throws IOException, HttpException;
79
80 /**
81 * Triggered when the underlying channel is ready for reading a
82 * new portion of the response entity through the corresponding
83 * content decoder.
84 * <p>
85 * If the content consumer is unable to process incoming content,
86 * input event notifications can be temporarily suspended using
87 * {@link IOControl} interface (super interface of {@link NHttpClientConnection}).
88 * <p>
89 * Please note that the {@link NHttpClientConnection} and {@link ContentDecoder}
90 * objects are not thread-safe and should only be used within the context of
91 * this method call. The {@link IOControl} object can be shared and used on other
92 * thread to resume input event notifications when the handler is capable of
93 * processing more content.
94 *
95 * @see NHttpClientConnection
96 * @see ContentDecoder
97 * @see IOControl
98 *
99 * @param conn HTTP connection that can produce a new portion of the
100 * incoming response content.
101 * @param decoder The content decoder to use to read content.
102 */
103 void inputReady(
104 NHttpClientConnection conn,
105 ContentDecoder decoder) throws IOException, HttpException;
106
107 /**
108 * Triggered when the underlying channel is ready for writing a next portion
109 * of the request entity through the corresponding content encoder.
110 * <p>
111 * If the content producer is unable to generate outgoing content,
112 * output event notifications can be temporarily suspended using
113 * {@link IOControl} interface (super interface of {@link NHttpClientConnection}).
114 * <p>
115 * Please note that the {@link NHttpClientConnection} and {@link ContentEncoder}
116 * objects are not thread-safe and should only be used within the context of
117 * this method call. The {@link IOControl} object can be shared and used on other
118 * thread to resume output event notifications when more content is made available.
119 *
120 * @see NHttpClientConnection
121 * @see ContentEncoder
122 * @see IOControl
123 *
124 * @param conn HTTP connection that can accommodate a new portion
125 * of the outgoing request content.
126 * @param encoder The content encoder to use to write content.
127 */
128 void outputReady(
129 NHttpClientConnection conn,
130 ContentEncoder encoder) throws IOException, HttpException;
131
132 /**
133 * Triggered when the connection is closed by the opposite end point
134 * (half-closed).
135 *
136 * @param conn half-closed HTTP connection.
137 */
138 void endOfInput(
139 NHttpClientConnection conn) throws IOException;
140
141 /**
142 * Triggered when no input is detected on this connection over the
143 * maximum period of inactivity.
144 *
145 * @param conn HTTP connection that caused timeout condition.
146 */
147 void timeout(
148 NHttpClientConnection conn) throws IOException, HttpException;
149
150 /**
151 * Triggered when the connection is closed.
152 *
153 * @param conn closed HTTP connection.
154 */
155 void closed(NHttpClientConnection conn);
156
157 /**
158 * Triggered if an error occurs during the HTTP exchange.
159 *
160 * @param conn HTTP connection that caused an I/O error
161 * @param ex exception
162 */
163 void exception(NHttpClientConnection conn, Exception ex);
164
165 }