org.axonframework.common.lock

Class PessimisticLockFactory.BackoffParameters

java.lang.Object

org.axonframework.common.lock.PessimisticLockFactory.BackoffParameters

Enclosing class:

PessimisticLockFactory

public static final class PessimisticLockFactory.BackoffParameters
extends Object

There are 3 values:

acquireAttempts This used to specify the maxium number of attempts to obtain a lock before we back off (throwing a LockAcquisitionFailedException if it does). A value of '-1' means unlimited attempts.

maximumQueued Maximum number of queued threads we allow to try and obtain a lock, if another thread tries to obtain the lock after the limit is reached we back off (throwing a LockAcquisitionFailedException). A value of '-1' means the maximum queued threads is unbound / no limit. NOTE: This relies on approximation given by ReentrantLock.getQueueLength() so the effective limit may be higher then specified. Since this is a back off control this should be ok.

lockAttemptTimeout Time permitted to try and obtain a lock per acquire attempt in milliseconds. NOTE: The lockAttemptTimeout of the first attempt is always zero, so max wait time is approximately (acquireAttempts - 1) * lockAttemptTimeout

Field Summary

Fields

Modifier and Type	Field and Description
int	acquireAttempts
int	lockAttemptTimeout
int	maximumQueued

Constructor Summary

Constructors

Constructor and Description
BackoffParameters(int acquireAttempts, int maximumQueued, int lockAttemptTimeout) Initialize the BackoffParameters using given parameters.

Method Summary

Modifier and Type	Method and Description
boolean	hasAcquireAttemptLimit()
boolean	hasAcquireQueueLimit()
boolean	maximumQueuedThreadsReached(int queueLength)

Methods inherited from class java.lang.Object

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

Field Detail

acquireAttempts

public final int acquireAttempts

maximumQueued

public final int maximumQueued

lockAttemptTimeout

public final int lockAttemptTimeout

Constructor Detail

BackoffParameters

public BackoffParameters(int acquireAttempts,
                         int maximumQueued,
                         int lockAttemptTimeout)

Initialize the BackoffParameters using given parameters.

Parameters:

acquireAttempts - the total number of attempts to make to acquire the lock. A value of -1 means indefinite attempts

maximumQueued - the threshold of the number of threads queued for acquiring the lock, or -1 to ignore queue size

lockAttemptTimeout - the amount of time to wait, in milliseconds, for each lock acquisition attempt

Method Detail

hasAcquireAttemptLimit

public boolean hasAcquireAttemptLimit()

hasAcquireQueueLimit

public boolean hasAcquireQueueLimit()

maximumQueuedThreadsReached

public boolean maximumQueuedThreadsReached(int queueLength)