Member Avatar for aravind326

Hi,

I have a java class that is being used by multiple people (from a UI).

In the class i have a static HashMap with the userKey as the map key and an arraylist with data pertaining to the user as the value. I am using this kind of like a cache. Because populating the list everytime the user logs in is a very expensive procedure.

Whenever a user logs in and modifies the data i am updating the list for that user in the map.

Now the issue is that I donot want to keep the entries in the HashMap forever. I need to clear the entries for users that have not been logged in for a while to be removed from the hashmap, but I do not want to clear the whole map.

I tried experimenting with WeakHashMap, but it didnt seem to work well with String keys.

Does anyone have any idea on what can be done in such a situation?

Any help is appreciated.

Thanks,
Aravind

  • 3 Contributors
  • 4 Replies
  • 388 Views
  • 4 Hours Discussion Span
  • Latest Post Latest Post by aravind326
Member Avatar for JamesCherrill

Why not just a scheduled clean-up that uses map.remove(key) to remove unwanted entries?

Member Avatar for aravind326

I was looking for something like an automated garbage collection similar to that in WeakHashMap.

If I have to do a scheduled cleanup, then I need to add more information into the map as to which entries has been recently used and which are not. Which would make stuff more complicated.

Member Avatar for aravind326

Thanks.

I think CacheBuilder would be perfect for my requirement.

Tried a sample class and it seems to work fine.

Now need to integrate with my app. Fingers crossed.

Be a part of the DaniWeb community

We're a friendly, industry-focused community of developers, IT pros, digital marketers, and technology enthusiasts meeting, networking, learning, and sharing knowledge.