Re: stock brocking web application

From:

=?ISO-8859-1?Q?Arne_Vajh=F8j?= <arne@vajhoej.dk>

Newsgroups:

comp.lang.java.programmer

Date:

Fri, 05 Sep 2008 22:53:12 -0400

Message-ID:

<48c1f099$0$90270$14726298@news.sunsite.dk>

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