We are developing and web application which allows users to register for certain events. What application is supposed to do, is to send them few notifications to remind them that they have registered. There will be more than 1k user which can register for many events in very wide time range. We have to send notofications like 3 months, 1 month, 1 week and one day before event.
The first thing is that I have to determine if I need to send notification to a specific user.
I’m thinking about thread which will iterate over registrations and determine whether sending notification is required or not. If notification is required, should I do it right away or maybe put all of the objects that need it in some kind of cache and then send them (by another thread)?
Second thing is: if I made that thread – is better to put it and run next to application or embed that thread into application and, for example, start it in the context listener?
How You would solve this? Maybe there are better approaches?
I would not spawn my own threads for that, I would use a scheduler like Quartz and run daily or hourly jobs (I don’t know what granularity you need) that would:
I would probably implement that using separate jobs (sending notifications is a different concern) and thus queue the results of the first part, this will give you more flexibility. And the first part could be done by a unique job scheduled with different time frame parameters (1 day, 1 week, 1 month, 3 months).