On 4/18/07, "Simon Räss" <[EMAIL PROTECTED]> wrote:
I'm using the current HEAD of commons-pool. I've had a look at the new composite classes, which look quite promising. I want to limit the total number of idle objects when using a KeyedObjectPool. I'd like to release objects using a (global) LRU algorithm. As far as I've seen, it is only possible to limit the idle objects per ObjectPool (using FactoryConfig.setMaxIdle, which causes an IdleLimitManager to be created). However, the Manager (as well as the Lender) object seems to be created per ObjectPool. Is it possible with the current design to remove the least recently used idle object from the keyed pool (irrespective of its kind)? Any implementation hints?
It's a desirable feature but I'd caution against adding it without making sure that feature doesn't negatively affect keyed pools that don't use it. The composite pool code implements a KeyedObjectPool as an ObjectPool per key and doesn't (currently) provide any global to the KeyedObjectPool features. This design allows the composite keyed pool to have improved performance in a multi-threaded environments because most of the synchronization is per key. If it supported global limits then you'd need to synchronize all keyed pool access so you can do cross key accounting and that would serialize access to the whole keyed pool instead of serialize access per key of the pool. With util.concurrent locking you could probably do this in a decently concurrent way, but that code has yet to be written. Without util.concurrentyou could add more smarts to the pool factory so it chooses another CompositeKeyedObjectPool implementation when global limits are used only people who use those features pay the performance penalty; again that code hasn't been written either. -- Sandy McArthur "He who dares not offend cannot be honest." - Thomas Paine
