//
// ========================================================================
// Copyright (c) 1995-2014 Mort Bay Consulting Pty. Ltd.
// ------------------------------------------------------------------------
// All rights reserved. This program and the accompanying materials
// are made available under the terms of the Eclipse Public License v1.0
// and Apache License v2.0 which accompanies this distribution.
//
// The Eclipse Public License is available at
// http://www.eclipse.org/legal/epl-v10.html
//
// The Apache License v2.0 is available at
// http://www.opensource.org/licenses/apache2.0.php
//
// You may elect to redistribute this code under either of these licenses.
// ========================================================================
//
package org.eclipse.jetty.server.handler;
import java.io.IOException;
import javax.servlet.AsyncContext;
import javax.servlet.DispatcherType;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.eclipse.jetty.server.Request;
/* ------------------------------------------------------------ */
/** A handler wrapper that provides the framework to asynchronously
* delay the handling of a request. While it uses standard servlet
* API for asynchronous servlets, it adjusts the dispatch type of the
* request so that it does not appear to be asynchronous during the
* delayed dispatch.
*
*/
public class AsyncDelayHandler extends HandlerWrapper
{
public final static String AHW_ATTR = "o.e.j.s.h.AsyncHandlerWrapper";
/* ------------------------------------------------------------ */
@Override
public void handle(String target, Request baseRequest, HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException
{
if (!isStarted() || _handler==null)
return;
// Get the dispatcher types
DispatcherType ctype = baseRequest.getDispatcherType();
DispatcherType dtype = (DispatcherType)baseRequest.getAttribute(AHW_ATTR);
Object async_context_path=null;
Object async_path_info=null;
Object async_query_string=null;
Object async_request_uri=null;
Object async_servlet_path=null;
// Is this request a restarted one?
boolean restart=false;
if (dtype!=null)
{
// fake the dispatch type to the original
baseRequest.setAttribute(AHW_ATTR,null);
baseRequest.setDispatcherType(dtype);
restart=true;
async_context_path=baseRequest.getAttribute(AsyncContext.ASYNC_CONTEXT_PATH);
baseRequest.setAttribute(AsyncContext.ASYNC_CONTEXT_PATH,null);
async_path_info=baseRequest.getAttribute(AsyncContext.ASYNC_PATH_INFO);
baseRequest.setAttribute(AsyncContext.ASYNC_PATH_INFO,null);
async_query_string=baseRequest.getAttribute(AsyncContext.ASYNC_QUERY_STRING);
baseRequest.setAttribute(AsyncContext.ASYNC_QUERY_STRING,null);
async_request_uri=baseRequest.getAttribute(AsyncContext.ASYNC_REQUEST_URI);
baseRequest.setAttribute(AsyncContext.ASYNC_REQUEST_URI,null);
async_servlet_path=baseRequest.getAttribute(AsyncContext.ASYNC_SERVLET_PATH);
baseRequest.setAttribute(AsyncContext.ASYNC_SERVLET_PATH,null);
}
// Should we handle this request now?
if (!startHandling(baseRequest,restart))
{
// No, so go async and remember dispatch type
AsyncContext context = baseRequest.startAsync();
baseRequest.setAttribute(AHW_ATTR,ctype);
delayHandling(baseRequest, context);
return;
}
// Handle the request
try
{
_handler.handle(target,baseRequest, request, response);
}
finally
{
if(restart)
{
// reset the request
baseRequest.setDispatcherType(ctype);
baseRequest.setAttribute(AsyncContext.ASYNC_CONTEXT_PATH,async_context_path);
baseRequest.setAttribute(AsyncContext.ASYNC_PATH_INFO,async_path_info);
baseRequest.setAttribute(AsyncContext.ASYNC_QUERY_STRING,async_query_string);
baseRequest.setAttribute(AsyncContext.ASYNC_REQUEST_URI,async_request_uri);
baseRequest.setAttribute(AsyncContext.ASYNC_SERVLET_PATH,async_servlet_path);
}
// signal the request is leaving the handler
endHandling(baseRequest);
}
}
/* ------------------------------------------------------------ */
/** Called to indicate that a request has been presented for handling
* @param request The request to handle
* @param restart True if this request is being restarted after a delay
* @return True if the request should be handled now
*/
protected boolean startHandling(Request request, boolean restart)
{
return true;
}
/* ------------------------------------------------------------ */
/** Called to indicate that a requests handling is being delayed/
* The implementation should arrange for context.dispatch() to be
* called when the request should be handled. It may also set
* timeouts on the context.
*
* @param request The request to be delayed
* @param context The AsyncContext of the delayed request
*/
protected void delayHandling(Request request,AsyncContext context)
{
context.dispatch();
}
/* ------------------------------------------------------------ */
/** Called to indicated the handling of the request is ending.
* This is only the end of the current dispatch of the request and
* if the request is asynchronous, it may be handled again.
* @param request The request
*/
protected void endHandling(Request request)
{
}
}