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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */


package org.apache.catalina.comet;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * The CometEvent interface.
 *
 * @author Filip Hanik
 * @author Remy Maucherat
 */
public interface CometEvent {

    /**
     * Enumeration describing the major events that the container can invoke
     * the CometProcessors event() method with.
* BEGIN - will be called at the beginning * of the processing of the connection. It can be used to initialize any relevant * fields using the request and response objects. Between the end of the processing * of this event, and the beginning of the processing of the end or error events, * it is possible to use the response object to write data on the open connection. * Note that the response object and dependent OutputStream and Writer are still * not synchronized, so when they are accessed by multiple threads, * synchronization is mandatory. After processing the initial event, the request * is considered to be committed.
* READ - This indicates that input data is available, and that one read can be made * without blocking. The available and ready methods of the InputStream or * Reader may be used to determine if there is a risk of blocking: the servlet * should read while data is reported available. When encountering a read error, * the servlet should report it by propagating the exception properly. Throwing * an exception will cause the error event to be invoked, and the connection * will be closed. * Alternately, it is also possible to catch any exception, perform clean up * on any data structure the servlet may be using, and using the close method * of the event. It is not allowed to attempt reading data from the request * object outside of the execution of this method.
* END - End may be called to end the processing of the request. Fields that have * been initialized in the begin method should be reset. After this event has * been processed, the request and response objects, as well as all their dependent * objects will be recycled and used to process other requests. End will also be * called when data is available and the end of file is reached on the request input * (this usually indicates the client has pipelined a request).
* ERROR - Error will be called by the container in the case where an IO exception * or a similar unrecoverable error occurs on the connection. Fields that have * been initialized in the begin method should be reset. After this event has * been processed, the request and response objects, as well as all their dependent * objects will be recycled and used to process other requests. */ public enum EventType {BEGIN, READ, END, ERROR} /** * Event details.
* TIMEOUT - the connection timed out (sub type of ERROR); note that this ERROR type is not fatal, and * the connection will not be closed unless the servlet uses the close method of the event
* CLIENT_DISCONNECT - the client connection was closed (sub type of ERROR)
* IOEXCEPTION - an IO exception occurred, such as invalid content, for example, an invalid chunk block (sub type of ERROR)
* WEBAPP_RELOAD - the webapplication is being reloaded (sub type of END)
* SERVER_SHUTDOWN - the server is shutting down (sub type of END)
* SESSION_END - the servlet ended the session (sub type of END) */ public enum EventSubType { TIMEOUT, CLIENT_DISCONNECT, IOEXCEPTION, WEBAPP_RELOAD, SERVER_SHUTDOWN, SESSION_END } /** * Returns the HttpServletRequest. * * @return HttpServletRequest */ public HttpServletRequest getHttpServletRequest(); /** * Returns the HttpServletResponse. * * @return HttpServletResponse */ public HttpServletResponse getHttpServletResponse(); /** * Returns the event type. * * @return EventType */ public EventType getEventType(); /** * Returns the sub type of this event. * * @return EventSubType */ public EventSubType getEventSubType(); /** * Ends the Comet session. This signals to the container that * the container wants to end the comet session. This will send back to the * client a notice that the server has no more data to send as part of this * request. The servlet should perform any needed cleanup as if it had received * an END or ERROR event. * * @throws IOException if an IO exception occurs */ public void close() throws IOException; /** * Sets the timeout for this Comet connection. Please NOTE, that the implementation * of a per connection timeout is OPTIONAL and MAY NOT be implemented.
* This method sets the timeout in milliseconds of idle time on the connection. * The timeout is reset every time data is received from the connection or data is flushed * using response.flushBuffer(). If a timeout occurs, the * error(HttpServletRequest, HttpServletResponse) method is invoked. The * web application SHOULD NOT attempt to reuse the request and response objects after a timeout * as the error(HttpServletRequest, HttpServletResponse) method indicates.
* This method should not be called asynchronously, as that will have no effect. * * @param timeout The timeout in milliseconds for this connection, must be a positive value, larger than 0 * @throws IOException An IOException may be thrown to indicate an IO error, * or that the EOF has been reached on the connection * @throws ServletException An exception has occurred, as specified by the root * cause * @throws UnsupportedOperationException if per connection timeout is not supported, either at all or at this phase * of the invocation. */ public void setTimeout(int timeout) throws IOException, ServletException, UnsupportedOperationException; }




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