001/*
002 * ====================================================================
003 * Licensed to the Apache Software Foundation (ASF) under one
004 * or more contributor license agreements.  See the NOTICE file
005 * distributed with this work for additional information
006 * regarding copyright ownership.  The ASF licenses this file
007 * to you under the Apache License, Version 2.0 (the
008 * "License"); you may not use this file except in compliance
009 * with the License.  You may obtain a copy of the License at
010 *
011 *   http://www.apache.org/licenses/LICENSE-2.0
012 *
013 * Unless required by applicable law or agreed to in writing,
014 * software distributed under the License is distributed on an
015 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
016 * KIND, either express or implied.  See the License for the
017 * specific language governing permissions and limitations
018 * under the License.
019 * ====================================================================
020 *
021 * This software consists of voluntary contributions made by many
022 * individuals on behalf of the Apache Software Foundation.  For more
023 * information on the Apache Software Foundation, please see
024 * <http://www.apache.org/>.
025 *
026 */
027
028package org.apache.http.nio;
029
030import java.io.IOException;
031
032import org.apache.http.HttpException;
033
034/**
035 * Abstract server-side HTTP event handler.
036 *
037 * @since 4.2
038 */
039public interface NHttpServerEventHandler {
040
041    /**
042     * Triggered when a new incoming connection is created.
043     *
044     * @param conn new incoming connection HTTP connection.
045     */
046    void connected(
047            NHttpServerConnection conn) throws IOException, HttpException;
048
049    /**
050     * Triggered when a new HTTP request is received. The connection
051     * passed as a parameter to this method is guaranteed to return
052     * a valid HTTP request object.
053     * <p>
054     * If the request received encloses a request entity this method will
055     * be followed a series of
056     * {@link #inputReady(NHttpServerConnection, ContentDecoder)} calls
057     * to transfer the request content.
058     *
059     * @see NHttpServerConnection
060     *
061     * @param conn HTTP connection that contains a new HTTP request
062     */
063    void requestReceived(
064            NHttpServerConnection conn) throws IOException, HttpException;
065
066    /**
067     * Triggered when the underlying channel is ready for reading a
068     * new portion of the request entity through the corresponding
069     * content decoder.
070     * <p>
071     * If the content consumer is unable to process incoming content,
072     * input event notifications can be temporarily suspended using
073     * {@link IOControl} interface (super interface of {@link NHttpServerConnection}).
074     * <p>
075     * Please note that the {@link NHttpServerConnection} and {@link ContentDecoder}
076     * objects are not thread-safe and should only be used within the context of
077     * this method call. The {@link IOControl} object can be shared and used on other
078     * thread to resume input event notifications when the handler is capable of
079     * processing more content.
080     *
081     * @see NHttpServerConnection
082     * @see ContentDecoder
083     * @see IOControl
084     *
085     * @param conn HTTP connection that can produce a new portion of the
086     * incoming request content.
087     * @param decoder The content decoder to use to read content.
088     */
089    void inputReady(
090            NHttpServerConnection conn,
091            ContentDecoder decoder) throws IOException, HttpException;
092
093    /**
094     * Triggered when the connection is ready to accept a new HTTP response.
095     * The protocol handler does not have to submit a response if it is not
096     * ready.
097     *
098     * @see NHttpServerConnection
099     *
100     * @param conn HTTP connection that contains an HTTP response
101     */
102    void responseReady(
103            NHttpServerConnection conn) throws IOException, HttpException;
104
105    /**
106     * Triggered when the underlying channel is ready for writing a
107     * next portion of the response entity through the corresponding
108     * content encoder.
109     * <p>
110     * If the content producer is unable to generate outgoing content,
111     * output event notifications can be temporarily suspended using
112     * {@link IOControl} interface (super interface of {@link NHttpServerConnection}).
113     * <p>
114     * Please note that the {@link NHttpServerConnection} and {@link ContentEncoder}
115     * objects are not thread-safe and should only be used within the context of
116     * this method call. The {@link IOControl} object can be shared and used on other
117     * thread to resume output event notifications when more content is made available.
118     *
119     * @see NHttpServerConnection
120     * @see ContentEncoder
121     * @see IOControl
122     *
123     * @param conn HTTP connection that can accommodate a new portion
124     * of the outgoing response content.
125     * @param encoder The content encoder to use to write content.
126     */
127    void outputReady(
128            NHttpServerConnection conn,
129            ContentEncoder encoder) throws IOException, HttpException;
130
131    /**
132     * Triggered when the connection is closed by the opposite end point
133     * (half-closed).
134     *
135     * @param conn half-closed HTTP connection.
136     */
137    void endOfInput(
138            NHttpServerConnection conn) throws IOException;
139
140    /**
141     * Triggered when no input is detected on this connection over the
142     * maximum period of inactivity.
143     *
144     * @param conn HTTP connection that caused timeout condition.
145     */
146    void timeout(
147            NHttpServerConnection conn) throws IOException;
148
149    /**
150     * Triggered when the connection is closed.
151     *
152     * @param conn closed HTTP connection.
153     */
154    void closed(NHttpServerConnection conn);
155
156    /**
157     * Triggered if an error occurs during the HTTP exchange.
158     *
159     * @param conn HTTP connection that caused an I/O error
160     * @param ex exception
161     */
162    void exception(NHttpServerConnection conn, Exception ex);
163
164}