Package io.hekate.lock

Interface AsyncLockCallback

public interface AsyncLockCallback

Callback for asynchronous locking operations.

Instances of this interface can be passed to the DistributedLock.lockAsync(Executor, AsyncLockCallback) method in order to get asynchronous notifications about lock status changes. Method of this interface are executed as follows:

• If locking attempt was successful then onLockAcquire(DistributedLock) method gets called. The acquired lock will be bound to the context of a callback thread (i.e. DistributedLock.isHeldByCurrentThread() will return true if called from the callback). Note that locks are not automatically released and it is up the callback implementation to decide when lock should be released. After lock gets released then the onLockRelease(DistributedLock) method will be called.
• If locking attempt failed because of the lock is being held by some other node/thread then onLockBusy(LockOwnerInfo) method will be called and another attempt to acquire the lock will be preform unless the lock gets acquired or operation gets cancelled.
• If callback is still waiting for the lock and lock owner changes then onLockOwnerChange(LockOwnerInfo) method will be notified and another attempt to acquire the lock will be preformed unless lock gets acquired or operation gets cancelled.

See Also:

DistributedLock.lockAsync(Executor, AsyncLockCallback)

Method Summary

Modifier and Type	Method	Description
void	onLockAcquire(DistributedLock lock)	Gets called when lock was successfully acquired.
default void	onLockBusy(LockOwnerInfo owner)	Gets called when initial attempt to acquire the lock failed because of the lock is being held by some other node or thread.
default void	onLockOwnerChange(LockOwnerInfo owner)	Gets called when lock owner changes while the callback is still waiting for the lock to be acquired.
default void	onLockRelease(DistributedLock lock)	Gets called after lock has been released.

Method Detail

onLockAcquire

void onLockAcquire(DistributedLock lock)

Gets called when lock was successfully acquired.

The acquired lock is bound to the thread that calls this method (i.e. DistributedLock.isHeldByCurrentThread() will return true if called within this method). Note that lock will NOT be automatically released after this methods finishes its execution. It is up to the implementation to decide when lock should be released.

Parameters:

lock - Lock.

onLockBusy

default void onLockBusy(LockOwnerInfo owner)

Gets called when initial attempt to acquire the lock failed because of the lock is being held by some other node or thread.

Note that lock will still remain in a waiting state after this method gets called and once the lock gets acquired then the onLockAcquire(DistributedLock) method will be called.

Parameters:

owner - Current lock owner.

onLockOwnerChange

default void onLockOwnerChange(LockOwnerInfo owner)

Gets called when lock owner changes while the callback is still waiting for the lock to be acquired.

Note that lock will still remain in a waiting state after this method gets called and once the lock gets acquired then the onLockAcquire(DistributedLock) method will be called.

Parameters:

owner - New lock owner.

onLockRelease

default void onLockRelease(DistributedLock lock)

Gets called after lock has been released. Note that this method gets called only if the lock was previously acquired.

Parameters:

lock - Released lock.