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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 }