I want the variable to be reset if the browser is closed. The browser could be closed while the report generation is in process (which is a separate thread). There seems to be no way for the server to know that the browser was closed. If I do not reset the session variable then I cannot start generating another report until the first report thread dies on the server.
-----Original Message----- From: Brett Connor [mailto:[EMAIL PROTECTED] Sent: Friday, July 23, 2004 10:06 AM To: Struts Users Mailing List Subject: Re: Intermediate loading page Surely the session variable will be reset by the report generation process, independent of any browser windows open, therefore no problem, you never need to know if the browser has been closed or not. Or have I misunderstood? Brett Rizwan Merchant wrote: >Thanks for the previous input. I moved the report generation to a >thread and set a session variable which is a boolean indicating that a >report is currently being generated. Once the report generation is >complete that session variable is set to false again. >I have come across another problem though. Say a user starts generating >a report. The boolean session variable is set to true. If the user >tries to generate another report while the fist oneis not complete, >then the boolean variable is checked and the user is not allowed to >generate another report (until the first one is complete and the >boolean session variable is set to false). > >In this scenario, if the user abruptly closes the intermediate page >which is supposed to load the report , then the session variable is >still set to true (indicating report is being generated) as the thread >on the server has not finished running. If the user now tries to create >another report then s/he will not be allowed to do so (until the thread >on the server is done running). > >So I guess my question is : Is there any way to set a session variable >when the user closes a browser window abruptly? >Or is there another way to approach this problem? > >Thanks, > >-Riz. > >-----Original Message----- >From: Craig McClanahan [mailto:[EMAIL PROTECTED] >Sent: Friday, July 16, 2004 5:23 PM >To: Struts Users Mailing List >Subject: Re: Intermediate loading page > >Rizwan Merchant wrote: > > > >>Hi Craig, >> >>Thanks for the reply. I came across this solution, but does this not >>mean that the user will only be able to generate one report at a time >>(since we are storing the flag in the user's session)? If the user >>starts generating a second report which is much smaller than the first >>then would this not create a problem? >> >> >> >> >> >You could accomodate such a thing in several different ways, but how >would the user even start requesting the second report? If they're >sitting on the auto-repeat "Please Wait" page, they won't have the >opportunity. If you want them to be able to go request a second report >while the first one is still generating, you'll probably be better off >just navigating back to the main menu (or something) after firing off >the first thread, then let them fire off a different thread (using a >different flag) for the second report >-- then have a screen where they can "pick up" their completed reports >and display them. > >If the computational effort to produce reports becomes severe, you >might also consider using some sort of job queueing package so that a >single background thread could do the report generation for all your >users (one report at a time). If you go this way, the "pick up your completed report" >page becomes an even better idea. > > > >>Thanks again for your input. Much appreciated. >> >>-Riz. >> >> >> >> >> >Craig > > > >>-----Original Message----- >>From: Craig McClanahan [mailto:[EMAIL PROTECTED] >>Sent: Friday, July 16, 2004 3:37 PM >>To: Struts Users Mailing List >>Subject: Re: Intermediate loading page >> >>Rizwan Merchant wrote: >> >> >> >> >> >>>I am working on a web application using the Struts framework. Using a >>>form on a jsp page, I generate a report which is displayed in pdf on >>>a new screen. The report is generated through an Action class method. >>>I would like to display a "Please wait" screen while the report is >>>being generated. >>> >>>The action class method calls functions that generate a pdf file and >>>then redirects control to that file. So I cannot use the flush() >>>method to send html to the browser while the report is being >>>generated (once a response is committed it cannot be written to >>>again). Neither can I use the 'div' tag method as my new page is not >>>a jsp page (it is a new browser window with pdf file displayed inside it). >>> >>> >>> >>> >>One common strategy for this sort of thing is to refactor your action >>into several, along the following lines: >> >>* The Action that is currently creating the PDF should instead fire >>off a background thread to do the report preparation. It will then >>forward to a "Please Wait" page (see below). >> >>* The background thread should do whatever is needed to prepare the >>PDF file, and set a flag variable in the user's session when it's >>done, followed by terminating the thread. >> >>* The "Please Wait" page should say something like "Report generation >>in progress", and use a meta-refresh tag to automatically submit >>itself every few seconds, with the destination being a "Done Yet" >>action. >> >>* The "Done Yet" action will consult the flag variable in the user's >>session. >> If its not there, forward back to the "Please Wait" page again. If >>it's done, forward to the URL to retrieve the PDF itself. >> >>Craig >> >> >> >> >> >> >>>My code is shown below.... >>> >>>//the jsp code calling the action >>><nested:form action="/reports.do?action=getTransactionReports" >>>target="_blank"> >>> >>> >>>// The Action class >>>public ActionForward getTransactionReports(ActionMapping mapping, >>>ActionForm form, HttpServletRequest request, HttpServletResponse >>>response) throws Exception { >>> >>>ICustomerAdministrationClient admin_impl = >>>getCustomerAdministrationService(request); >>> >>>//enforce user permission >>>enforceFeaturePermissions(EMSConstants.FEATURE_REPORTS, request, 1); >>> >>>EMSBaseAdminForm admin_form = (EMSBaseAdminForm)form; ReportsForm >>>reportsForm = admin_form.getReportsForm(); >>> >>>//cant do this as it creates an IllegalStateException // PrintWriter >>>html = response.getWriter(); // // >>>html.print("<html>\n<head><title>my >>>test</title></head>\n<body>"); // html.print("<p><img >>>src=\"images/dpt_logo.jpg\"></body></html>"); >>>// html.flush(); >>>// html.close(); >>> >>> >>>//if details type is summary then output format can only be PDF >>>if(reportsForm.getDetailsType().equals(EMSConstants.REPORTS_SUMMARY)) >>>reportsForm.setOutputFormat(EMSConstants.REPORTS_FORMAT_PDF); >>> >>>//generate the reports using jasper reports >>>doJasperReports(reportsForm, request); >>> >>>CustomerForm customer_form = (CustomerForm)getSessionObject(request, >>>"customerForm"); >>>Collection all_region_list_forms = >>>(Collection)getSessionObject(request, "allRegionListForms"); >>> >>>admin_form.setCustomerForm(customer_form); >>>admin_form.setRegionListForms(all_region_list_forms); >>>request.setAttribute(EMSConstants.FORM_VIEW, admin_form); >>> >>>String relativePath = File.separator + "temp_" + >>>request.getSession().getId(); String pdfFilePath = File.separator + >>>"temp" + relativePath + File.separator + "ReportinPDF.pdf"; String >>>csvFilePath = File.separator + "temp" + relativePath + File.separator >>>+ "ReportinCSV.dpt"; >>> >>>if(reportsForm.getOutputFormat().equals(EMSConstants.REPORTS_FORMAT_P >>>D >>>F)) return (new ActionForward(pdfFilePath, true)); >>> >>>return (new ActionForward(csvFilePath, true)); } >>> >>> >>>Any help would be appreciated. Thanks. >>>--------------------------------------------------------------------- >>>- >>>-- >>> >>><http://www.digitalpaytech.com/> >>> >>> >>> >>>Rizwan Merchant - Software Developer >>>4105 Grandview Highway, Burnaby, BC, V5C 6B4, Canada >>>Email: [EMAIL PROTECTED] >>><mailto:[EMAIL PROTECTED]> >>>Phone: 604-688-1959 x243 Fax: 604-687-4329 >>>Toll Free: 1-888-687-6822 >>>Website: www.digitalpaytech.com <outbind://11/www.digitalpaytech.com> >>> >>> >>> >>> >>> >>> >>> >> >>--------------------------------------------------------------------- >>To unsubscribe, e-mail: [EMAIL PROTECTED] >>For additional commands, e-mail: [EMAIL PROTECTED] >> >> >> >>--------------------------------------------------------------------- >>To unsubscribe, e-mail: [EMAIL PROTECTED] >>For additional commands, e-mail: [EMAIL PROTECTED] >> >> >> >> > > >--------------------------------------------------------------------- >To unsubscribe, e-mail: [EMAIL PROTECTED] >For additional commands, e-mail: [EMAIL PROTECTED] > > > >--------------------------------------------------------------------- >To unsubscribe, e-mail: [EMAIL PROTECTED] >For additional commands, e-mail: [EMAIL PROTECTED] > > > > --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
