I'm finding LockContainer and its implementations such as ReentrantPerEntryLockContainer very useful in other projects for example when you wanna maintain some kind of per-key locks.

However, discussing with Brian, he made a good point about the LockContainer API:

boolean acquireLock(Object key, long timeout, TimeUnit unit) throws InterruptedException;

Lock getLock(Object key);

Sometimes, you wanna acquire the lock and keep the lock around. To do so right now, u have to make two calls, one to acquireLock and one to getLock. It'd be better if acquireLock was enhanced to be this way:

Lock acquireLock(Object key, long timeout, TimeUnit unit) throws InterruptedException;

So, if acquireLock suceeds, it returns the lock immediately. If it doesn't, it could simply return null.

WDYT?