Package locklib

In locklib, a locking target is represented by a Target.

See: Description

Interface Summary

Interface	Description
LockManagerListener<LockType>	Interface implemented by objects that are informed of changes in the locks currently held.
LockPolicy<LockType>	A lock policy defines how a locking mechanism works.
LockPreChecker<LockType>	A lock pre-checker is informed of all locks currently held and decides whether a lock (which cannot be obtained right now) can be queued for later acquisition.
WaitQueueFactory<LockType>	Factory that creates wait queues for targets.

Class Summary

Class	Description
FifoWaitQueue<LockType>	Wait queue that keeps requests in a FIFO queue.
FifoWaitQueueFactory<LockType>	Factory that creates FifoWaitQueue.
LockGrant<LockType>	A lock grant represents the successful acquisition of a lock.
LockGrantFuture<LockType>	Future representing a request for a lock grant.
LockManager<LockType>	The lock manager holds information about all locks currently held and all locks currently being waited for.
LockRequest<LockType>	Request for a lock.
NullLockPreChecker<LockType>	Lock pre-checker that accepts waiting for all locks, possibly generating a deadlock.
Target<LockType>	A target is an object that can be locked.
WaitQueue<LockType>	A wait queue manages lock requests that are pending for a target, deciding in which order should the locks be obtained.

Exception Summary

Exception	Description
CyclicTargetHierarchyException	Exception thrown setting the parent of a target would make a cycle.
DifferentLockManagersException	Exception thrown setting the parent of a target to a target that has a different lock manager.
HierarchyChangeBreaksChainException	Exception thrown when changing the target hierarchy would break existing lock chains.
LockCancelledException	Exception thrown when a lock is cancelled by another thread and the current thread was waiting for the lock.
NotLockedException	Exception thrown when an operation expecting a locked lock finds an unlocked lock.

Package locklib Description

In locklib, a locking target is represented by a Target. All locks are managed by a LockManager. Holders can be any java object.

To request a lock, a LockRequest is created and requested to the target using Target.lock(LockRequest). This method returns a LockGrantFuture, an object that can be used to synchronously or asynchronously obtain the lock. A lock itself is represented by a LockGrant (which can be obtained from the LockGrantFuture). To release a lock, the LockGrant.release() method should be used.