Custom JSP taglib. Lets you simulate scheduler (or cron tab requests) right in your JSP pages.
The idea is very simply. You can "borrow" requests from the visitors of your site. Of course, it assumes that your
site consistently get visitors at a frequency greater than your schedulerís interval. You can add to your site a hidden
(invisible) iframe where src attribute points to the "scheduler". And your "scheduler" will perform the
requests to your periodical tasks (implemented as JSP pages or servlets). Your periodical tasks could be long running of course, so
the direct request may delays site response to the visitors. And the more practical approach is
will asynchronously send you HTTP requests in the background (typically not visible to the user).
Of course it only works if your application has visitors who use web browsers, not if it only consumed by programs (e.g. through RSS feeds or other XML format).
Body tag Fork lets you write such a "scheduler". For example:
<%@ taglib uri="taglib.tld" prefix="f" %>
<f:Fork url="my_periodical_task.jsp" frequency="2"/>
You can perform requests for the each visitor or set some restrictions. For example you can perform requests for the each
"n-th" visitor only (attribute frequency) or set a minimal time between the requests (attribute minTime).
Body tag lets you implement "pseudo" scheduler. Attributes are:
1) url Describes a requested URL for your task.
See also Coldtags suite - the largest collection of custom JSP tags.
Also in Coldtags: