com.github.cloudyrock.mongock.driver.core.lock

Class DefaultLockManager

java.lang.Object

com.github.cloudyrock.mongock.driver.core.lock.DefaultLockManager

All Implemented Interfaces:

LockManager, Closeable, AutoCloseable

@NotThreadSafe
public class DefaultLockManager
extends Object
implements LockManager

This class is responsible of managing the lock at high level. It provides 3 main methods which are for acquiring, ensuring(doesn't acquires the lock, just refresh the expiration time if required) and releasing the lock.

Implementation note: This class is not thread safe. If in future development thread safety is needed, please consider using volatile for expiresAt field and synchronized mechanism.

Constructor Summary

Constructors

Constructor and Description
DefaultLockManager(LockRepository repository, TimeService timeUtils) Constructor takes some bean injections

Method Summary

Modifier and Type	Method and Description
void	acquireLockDefault() Tries to acquire the default lock regardless who is the current owner.
void	clean()
void	close() release the default lock.
void	ensureLockDefault() Tries to refresh the default lock when the current LockChecker has the lock or , when the lock is expired, is the last owner
int	getLockMaxTries()
String	getOwner()
boolean	isLockHeld()
void	releaseLockDefault() Release the default lock when is acquired by the current LockChecker.
DefaultLockManager	setLockAcquiredForMillis(long lockAcquiredForMillis) Indicates the number of milliseconds the lock will be acquired for
DefaultLockManager	setLockMaxTries(int lockMaxTries) Updates the maximum number of tries to acquire the lock, if the flag 'waitForLog' is set
DefaultLockManager	setLockMaxWaitMillis(long lockMaxWaitMillis) If the flag 'waitForLog' is set, indicates the maximum time it will wait for the lock in each try.

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.github.cloudyrock.mongock.driver.api.lock.LockManager

getDefaultKey

Constructor Detail

DefaultLockManager

public DefaultLockManager(LockRepository repository,
                          TimeService timeUtils)

Constructor takes some bean injections

Parameters:

repository - lock repository

timeUtils - time utils service

Method Detail

acquireLockDefault

public void acquireLockDefault()
                        throws LockCheckException

Tries to acquire the default lock regardless who is the current owner.

If the lock is already acquired by the current LockChecker or is expired, will be updated

In case the lock is acquired by another LockChecker, it will wait until the current lock is expired and will try to acquire it again. This will be repeated as many times as (maxTries - 1)

Specified by:

acquireLockDefault in interface LockManager

Throws:

LockCheckException - if the lock cannot be acquired

ensureLockDefault

public void ensureLockDefault()
                       throws LockCheckException

Tries to refresh the default lock when the current LockChecker has the lock or , when the lock is expired, is the last owner

Notice that it does not try to acquire when is acquired by another LockChecker

Specified by:

ensureLockDefault in interface LockManager

Throws:

LockCheckException - if, in case of needed, the lock cannot be refreshed

releaseLockDefault

public void releaseLockDefault()

Release the default lock when is acquired by the current LockChecker.

When the lock is not acquired by the current LockChecker, it won't make any change. Does not throw any exception neither.

Idempotent operation.

Specified by:

releaseLockDefault in interface LockManager

close

public void close()

release the default lock. Useful in try/catch blocks

Specified by:

close in interface LockManager

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

setLockMaxWaitMillis

public DefaultLockManager setLockMaxWaitMillis(long lockMaxWaitMillis)

If the flag 'waitForLog' is set, indicates the maximum time it will wait for the lock in each try.

Default 3 minutes

Specified by:

setLockMaxWaitMillis in interface LockManager

Parameters:

lockMaxWaitMillis - max waiting time for lock. Must be greater than 0

Returns:

LockChecker object for fluent interface

getLockMaxTries

public int getLockMaxTries()

Specified by:

getLockMaxTries in interface LockManager

Returns:

max tries

setLockMaxTries

public DefaultLockManager setLockMaxTries(int lockMaxTries)

Updates the maximum number of tries to acquire the lock, if the flag 'waitForLog' is set

Default 1

Specified by:

setLockMaxTries in interface LockManager

Parameters:

lockMaxTries - number of tries

Returns:

LockChecker object for fluent interface

setLockAcquiredForMillis

public DefaultLockManager setLockAcquiredForMillis(long lockAcquiredForMillis)

Indicates the number of milliseconds the lock will be acquired for

Default 3 minutes

Specified by:

setLockAcquiredForMillis in interface LockManager

Parameters:

lockAcquiredForMillis - milliseconds the lock will be acquired for

Returns:

LockChecker object for fluent interface

getOwner

public String getOwner()

Specified by:

getOwner in interface LockManager

isLockHeld

public boolean isLockHeld()

Specified by:

isLockHeld in interface LockManager

clean

public void clean()

Specified by:

clean in interface LockManager