/*
* 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;
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.<br>
* 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.<br>
* 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.<br>
* 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).<br>
* 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.<br>
* 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<br>
* CLIENT_DISCONNECT - the client connection was closed (sub type of ERROR)<br>
* IOEXCEPTION - an IO exception occurred, such as invalid content, for example, an invalid chunk block (sub type of ERROR)<br>
* WEBAPP_RELOAD - the webapplication is being reloaded (sub type of END)<br>
* SERVER_SHUTDOWN - the server is shutting down (sub type of END)<br>
* 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 recieved
* 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.<br/>
* 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 <code>response.flushBuffer()</code>. If a timeout occurs, the
* <code>error(HttpServletRequest, HttpServletResponse)</code> method is invoked. The
* web application SHOULD NOT attempt to reuse the request and response objects after a timeout
* as the <code>error(HttpServletRequest, HttpServletResponse)</code> method indicates.<br/>
* 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;
}