Why not store the info in the servlet context, using different keys for each server?
That way if several users are all monitoring the same server they will be looking at the same set of data. Since the data is being multithreaded you will need to make sure you synchronize in the appropriate places for which purpose you would probably implement some kind of bean to store this data in an internal collection. You would probably want to merge the functionality of your polling bean with this storeage one, so you would be using one bean instance per server, with all users sharing these beans simultaneously. Id suggest that when the bean is asked to pull data for a particular server it checks to see that a certain period of time has gone by since the last poll. If not you wouldnt bother pulling another value to add to the set.(Id suggest at least a second, and more if you have lots of users). If two users ask for the information within a few milliseconds if each other there is little point doing an extra poll. By the time the graph is redrawn and hits the browser even the most current value will be many milliseconds out of date anyhow and it doesnt make much difference to a human! In terms of 'realtime' presentation you probably dont really want to have the browsers polling the server too much (though it would be easy to do with a javascript timer that refreshes the page), as all the requests will add considerably to your server load (especially since the charts need redrawing). If your setting a minimum polling period as suggested above you would probably also want to try and somehow cache the resulting chart images until such time as new data is available, such that several requests coming in rapidly (probably from different users) could all be serviced with the same image and cut the need to spend server time re-rendering the chart. Thats just my 2 cents worth though so theres probably many better ways of doing it. hth Andrew -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Sent: Wednesday, 26 May 2004 19:42 To: [EMAIL PROTECTED] Subject: scope and presenting realtime data (fwd) Hi, Can anyone suggest some approach for this issue. thanks & regards -Ramudu ---------- Forwarded message ---------- Date: Wed, 26 May 2004 14:52:23 +0530 (IST) From: [EMAIL PROTECTED] Reply-To: Struts Users Mailing List <[EMAIL PROTECTED]> To: [EMAIL PROTECTED] Subject: scope and presenting realtime data Hi, We are developing a web based interface (struts + jsp etc) for realtime monitoring of server cpu usage. We have written a bean that will contact the server and get the current cpu usage and return that value. I want to plot a line graph (using jfreechart) with the cpu usage in Y-axis and time in X-axis. The Graph need to plot the last 'N' values + the current value during each refresh. The issue is how to remember these last N values. I do not want to assign session scope for this object as the end-user might monitor for more than one servers and several users might be using the system at same time. How this situation is typically handled in the Struts+jsp environment. thanks & regards -Ramudu --------------------------------------------------------------------- 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]
