sirius.biz.locks

Class Locks

java.lang.Object

sirius.biz.locks.Locks

All Implemented Interfaces:

sirius.kernel.health.metrics.MetricProvider

public class Locks
extends Object
implements sirius.kernel.health.metrics.MetricProvider

Provides a central framework to obtain and manage named locks.

These locks can either be distributed (via SQL or REDIS) or held locally. The implementation is provided via a LockManager.

Field Summary

Fields

Modifier and Type	Field and Description
static String	FRAMEWORK_LOCKS Names the framework which must be enabled to activate the locks feature.
static sirius.kernel.health.Log	LOG

Constructor Summary

Constructors

Constructor and Description
Locks()

Method Summary

Modifier and Type	Method and Description
void	gather(sirius.kernel.health.metrics.MetricsCollector collector)
List<LockInfo>	getLocks() Returns a list of all currently held locks.
boolean	isLocked(String lock) Determines if the given lock is currently locked.
boolean	tryLock(String lockName, Duration acquireTimeout) Tries to acquire the given lock in the given timeslot.
void	tryLocked(String lock, Duration acquireTimeout, Runnable lockedTask) Boilerplate method to perform the given task while holding the given lock.
void	unlock(String lock) Releases the lock.
void	unlock(String lock, boolean force) Releases the given lock.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

FRAMEWORK_LOCKS

public static final String FRAMEWORK_LOCKS

Names the framework which must be enabled to activate the locks feature.

See Also:

Constant Field Values

LOG

public static final sirius.kernel.health.Log LOG

Constructor Detail

Locks

public Locks()

Method Detail

tryLock

public boolean tryLock(@Nonnull
                       String lockName,
                       @Nullable
                       Duration acquireTimeout)

Tries to acquire the given lock in the given timeslot.

A sane value for the timeout might be in the range of 5-50s, highly depending on the algorithm being protected by the lock. If the value is null, no retries will be performed.

Parameters:

lockName - the name of the lock to acquire

acquireTimeout - the max duration during which retires will be performed

Returns:

true if the lock was acquired, false otherwise

tryLocked

public void tryLocked(@Nonnull
                      String lock,
                      @Nullable
                      Duration acquireTimeout,
                      @Nonnull
                      Runnable lockedTask)

Boilerplate method to perform the given task while holding the given lock.

See tryLock(String, Duration) for details on acquiring a lock.

If the lock cannot be acquired, nothing will happen (neighter the task will be execute nor an exception will be thrown).

Parameters:

lock - the name of the lock to acquire

acquireTimeout - the max duration during which retires will be performed

lockedTask - the task to execute while holding the given lock. The task will not be executed if the lock cannot be acquired within the given period

isLocked

public boolean isLocked(@Nonnull
                        String lock)

Determines if the given lock is currently locked.

Parameters:

lock - the lock to check

Returns:

true if the lock is currently active, false otherwise

unlock

public void unlock(String lock)

Releases the lock.

Parameters:

lock - the lock to release

unlock

public void unlock(String lock,
                   boolean force)

Releases the given lock.

Parameters:

lock - the lock to release

force - if true, the lock will even be released if it is held by another node. This is a very dangerous operation and should only be used by maintenance and management tools.

gather

public void gather(sirius.kernel.health.metrics.MetricsCollector collector)

Specified by:

gather in interface sirius.kernel.health.metrics.MetricProvider

getLocks

public List<LockInfo> getLocks()

Returns a list of all currently held locks.

Returns:

a list of all locks