Hello. Steve Kirk wrote: > > Not sure if this is stating the obvious,
No, it doesn't. > or this is the approach you've > already taken, but it's not necesary to refresh the whole page that is > displaying your data every few seconds. You can have an invisible frame > that runs the JS timer that you describe. That frame could have > src="/mywebapp/DataUpdateCheck" which is a servlet that returns just a > simple js function - if there is new data, the function reloads it into the > visible frame, otherwise it reloads itself after a couple of seconds to > check for more data. Well, it's not the page/frame itself doing the refresh, but in fact the frame definition page, which includes the refresh code. There is also another timer, which creates some blinking (requested by the customer ;-) ) by changing the css classes of some HTML objects in about half second intervals. Do you have some example code of how this works ? I guess this seems to be a stupid question for somebody creating some more or less complex JSP+JavaScript Web application, but what exactly is a servlet ? Of course I heard this a lot. Is it some Java class ? How do would I make this known to Tomcat ? Some pointers (links) to good online documention for this ? I didn't know about the <META HTTP-EQUIV="Refresh" Content="1;URL=/GuiDeBook/"> mentioned by Edoardo Panfili, but I cannot use it here anyway, because by some keyborad input (function key) in another frame, I must be able to stop the updateing immediately (i.e. not realoding the page before). The user can then use the scroll keys to select a value in that frame, while usually the focus remains in the primary input frame. To make "sure" the user doesn't try to switch the mode, while currently updating (and for general information) I show the remaining time in another (third) frame, together with some additional information (a "legend" for the refreshing frame, or selectable values an input field in the main input frame). All this works quite well now (besides some trouble with database sessions, which see to be solved, too). But this is used to create orders for driverless vehicles and it would be nice to have it more to the time and/or less "flaschy". With kind regards, Harald Henkel > > > -----Original Message----- > > From: Steve Kirk [mailto:[EMAIL PROTECTED] > > Sent: Tuesday 19 October 2004 12:41 > > To: 'Tomcat Users List'; [EMAIL PROTECTED] > > Subject: RE: Push-Server with Tomcat > > > > > > > > Seems to me that browsers are inherently "pull" technology > > because at the > > basic level they send a single request and await a single > > response to it. > > You can't push stuff at them that they haven't requested. > > Hence why you > > have to use an approach like your javascript - which, by the > > way, I have > > used in the past in a web-based control system without > > problems - it might > > not feel that elegant, but it does work. > > > > I would think that to get a true push approach you would have > > to extend the > > browser capabilities using a plugin of some sort, e.g. java > > applet / activex > > / etc. Never tried this myself though so can't comment if > > this will solve > > it. > > > > > -----Original Message----- > > > From: Harald Henkel [mailto:[EMAIL PROTECTED] > > > Sent: Tuesday 19 October 2004 09:51 > > > To: Tomcat Users List > > > Subject: Push-Server with Tomcat > > > > > > > > > Hello everybody. > > > > > > Is it possible (with Tomcat) to write an application that, > > > once startet > > > will send a new HTML page to a client, genereated using changed data > > > from a database ? > > > > > > What I want to do is using oracle alerts to alert a waiting Tomcat > > > thread of changed data, let it collect the data and generate > > > one or more > > > HTML pages sent to different clients, i.e. a specific frame in the > > > browser on the client. > > > > > > Or would I have to have a Java app runing in that frame ? > > > > > > At the moment I'm doing this using a JavaScript timer on the client > > > requesting a new page for that frame every couple of seconds, > > > but for this application push would really be better. > > > > > > With kind regards, > > > Harald Henkel > > > > > > -- > > > Harald Henkel > > > > > > GS automation GmbH > > > Winterstra�e 2 > > > 82223 Eichenau > > > Germany > > > Tel: + 49-8141-35 731-37 > > > Fax: + 49-8141-35 731-38 > > > Mobile: + 49-178-7829126 > > > e-mail: [EMAIL PROTECTED] > > > Web: www.GS-automation.DE > > > > > > > > --------------------------------------------------------------------- > > > 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] -- Harald Henkel GS automation GmbH Winterstra�e 2 82223 Eichenau Germany Tel: + 49-8141-35 731-37 Fax: + 49-8141-35 731-38 Mobile: + 49-178-7829126 e-mail: [EMAIL PROTECTED] Web: www.GS-automation.DE --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
