Java Collection implementaiton with timeout of the elements

Question

Is there some collection implementation supporting expiration of the elements.

For example:

Collection<User> cachedUsers = new ExpirableList<User>(10000);

where

public ExpirableList(final long timeout){...}

And after given time (10000ms in this particular example), added elements will be removed from the collection. By using this, we will prevent overflow of our cachedUsers collection.

Looks like you are looking for... a cache: http://stackoverflow.com/questions/9352864 — Tomasz Nurkiewicz, Feb 20 '12 at 15:27

score 10 · Accepted Answer · edited Oct 14 '15 at 20:05

10

Yes, Guava supports a cache with timed expiration. See Guava Explained's page on caches.

An alternative is an LRU (least-recently used) cache that disposes of the oldest accessed element when a new element is inserted.

edited Oct 14 '15 at 20:05

Markus Patt

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answered Feb 20 '12 at 15:26

Andy Thomas

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score 3 · Answer 2 · answered Feb 20 '12 at 15:27

3

It's not really clear how you're trying to use the collection, but Guava's CacheBuilder may help you.

answered Feb 20 '12 at 15:27

Jon Skeet

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score 2 · Answer 3 · edited May 23 '17 at 10:34

2

You could implement this by writing a wrapper for, say, a TreeMap where you let the insertion time be the key. On each insert, you could drop the head list which has "timed out".

Using insertion time as an indication on whether or not in should be dropped seems like a bad idea though. It seems better to go with some LRU (least recently used) cache for instance. Such caches are readily available in libraries such as EHCache for instance. Don't reinvent the wheel.

Related questions:

edited May 23 '17 at 10:34

Community

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answered Feb 20 '12 at 15:26

aioobe

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Insertions committed at the same time are very rare, ain't they? – Oleg Mikheev Feb 20 '12 at 15:35
Haha. Good point. Solution is obviously to let each timestamp map to a set of objects :-) – aioobe Feb 20 '12 at 15:37

Java Collection implementaiton with timeout of the elements

3 Answers3