> -----Original Message----- > From: Rizwan Merchant [mailto:[EMAIL PROTECTED] > Sent: Friday, July 23, 2004 10:18 AM > To: 'Struts Users Mailing List' > Subject: RE: Intermediate loading page > > > > 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.
Earlier I had mentioned that this couldn't be done... however I forgot about that nefarios evil called javascript. There might be a way using that to send you a cancel url.... on the other hand it is javascript. > > > -----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.REPORT > S_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] > > --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
