You should consider looking at AJAX for this type of processing.
With AJAX you can store rules and processes in the user session object.
Changes can be made to happen without refreshing the whole page. It eliminates
a lot of request/response processing. Also consider fragment caching your
pages. This way, when you have to create a new request/response, only the
changed portion of your page is actually updated on the app server. The rest
of the page will be returned for cache.
We are doing this now because we have been forced to convert a ton of old green
screen Cobol CICS applications to web applications. We had used Jacada to
convert the screens to web apps (before my time here), but the users liked the
green scrrens better because they were faster. AJAX has proved to be as
efficient and as popular as the green screen.
G.
John MccLain <[EMAIL PROTECTED]> wrote: We have a fairly large client/server
app that we converted to a java webapp.
The original app was in powerbuilder. there were 2 types of rules applied to
field rendering:
1) any rule that could be handled when the screen loaded was handled via
screen level events, e.g., if a screen had fields with default values, or
hidden fields under certain conditions, then these would be applied at
screen entry via an onchange event for the screen
2) computed fields were handled via onChange events on the field, e.g., if
field x changes, change field y
The 'field rules' could be any valid powerscript expression
What we have done is mimicked this in java. we process the same way as
above, except we dynamically convert (very painfully) the powerscript into
java syntax, then run the rules as above, by passing the converted rules to
an embedded java interpreter (BeanShell)
The problem is if you have sophisticated rules, or rules which affect many
different fields, e.g., if field x changes, change field y, but if field y
changes, change field z, etc... This becomes very slow - up to 15 seconds
for a screen to render or change completely. Not to mention the complexity
of the rules management.
Is there a better way???
John McClain
Senior Software Engineer
TCS Healthcare
[EMAIL PROTECTED]
(530)886-1700x235
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