io.flamingock.internal.core.external.store.lock

Interface LockService

All Known Subinterfaces:

CommunityLockService

public interface LockService

Repository interface to manage lock in database, which will be used by LockManager

Method Summary

Modifier and Type	Method and Description
LockAcquisition	extendLock(LockKey key, io.flamingock.internal.util.id.RunnerId owner, long leaseMillis) The only goal of this method is to update(mainly to extend the expiry date) the lock in case is already owned.
LockAcquisition	getLock(LockKey lockKey) Retrieves a lock by key
void	releaseLock(LockKey lockKey, io.flamingock.internal.util.id.RunnerId owner) Removes from database all the locks with the same key(only can be one) and owner

Method Detail

extendLock

LockAcquisition extendLock(LockKey key,
                           io.flamingock.internal.util.id.RunnerId owner,
                           long leaseMillis)
                    throws LockServiceException

The only goal of this method is to update(mainly to extend the expiry date) the lock in case is already owned. So it requires a Lock for the same key and owner (existingLock.key==newLock.key && existingLoc.owner==newLock.owner).

If there is no lock for the key, or it doesn't belong to newLock.owner(), a LockPersistenceException is thrown.

Take into account that if it's already expired, but still with the same owner, we are lucky, no one has taken it yet, so we can still extend the expiration time.

Parameters:

key - Specially important in cloud execution as it represents a service

owner - It references the running instance

leaseMillis - How long(in millis) the lock will be acquired for.

Returns:

the lockAcquisition with the owner and leaseMillis, among others

Throws:

LockServiceException - if there is a lock in database with same key, but is expired and belong to another owner or cannot insert/update the lock for any other reason

getLock

LockAcquisition getLock(LockKey lockKey)

Retrieves a lock by key

Parameters:

lockKey - key

Returns:

LockEntry

releaseLock

void releaseLock(LockKey lockKey,
                 io.flamingock.internal.util.id.RunnerId owner)

Removes from database all the locks with the same key(only can be one) and owner

Parameters:

lockKey - lock key

owner - lock owner