Deleting a record after a period of time or when the specified time reaches automatically in Java-Collection of common programming errors

11 years ago
admin
2 minutes

I’m developing a Java web application. The scenario is described below:

  • Many users submit their status and they can see others’ statuses as well. It looks like a kind of social network.

  • Their statuses have a period of time to display, after this period, their statuses in database will be deleted.

  • At the time their statuses are deleted, send a notification to all users to request an update (the deleted statuses have to be vanished in realtime!)

I’ve tried to do that automatically by a thread in the Java web application. However, I’m stuck at some problems:

+Is it possible to manage database like that? I’ve thought of database event, but when a record is deleted, I will not be noticed.

+I’m using web socket to make the application work in realtime. If a person update a new status or change it, it’s possible to send an update notification to all of the users by using web socket. But when the changes come from database, I don’t know how to send a notification like that.

Can you give me some ideas? Thank you in advanced!

  1. You can use DelayQueue to store each item to be removed at a specified delay,and when you are removing the item,remove the record in database and send a notify to browser.

  2. If you need the statuses to be deleted even if your program crashes, then I recommend that you use quartz – this way if your program crashes then quartz will update the database when you re-load your program. If your program doesn’t need to be this robust then use a DelayQueue instead.