net.javacrumbs.shedlock.support

Class StorageBasedLockProvider

java.lang.Object

net.javacrumbs.shedlock.support.StorageBasedLockProvider

All Implemented Interfaces:

LockProvider

public class StorageBasedLockProvider
extends Object
implements LockProvider

Distributed lock using abstract storage

It uses a table/collection that contains ID = lock name and a field locked_until.

1. Attempts to insert a new lock record. As an optimization, we keep in-memory track of created lock records. If the record has been inserted, returns lock.
2. We will try to update lock record using filter ID == name AND lock_until <= now
3. If the update succeeded (1 updated row/document), we have the lock. If the update failed (0 updated documents) somebody else holds the lock
4. When unlocking, lock_until is set to now.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	StorageBasedLockProvider(StorageAccessor storageAccessor)

Method Summary

Modifier and Type	Method and Description
void	clearCache() Clears cache of existing lock records.
protected boolean	doLock(LockConfiguration lockConfiguration) Sets lockUntil according to LockConfiguration if current lockUntil <= now
Optional<SimpleLock>	lock(LockConfiguration lockConfiguration)

Methods inherited from class java.lang.Object

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

Constructor Detail

StorageBasedLockProvider

protected StorageBasedLockProvider(StorageAccessor storageAccessor)

Method Detail

clearCache

public void clearCache()

Clears cache of existing lock records.

lock

public Optional<SimpleLock> lock(LockConfiguration lockConfiguration)

Specified by:

lock in interface LockProvider

Returns:

If empty optional has been returned, lock could not be acquired. The lock has to be released by the callee.

doLock

protected boolean doLock(LockConfiguration lockConfiguration)

Sets lockUntil according to LockConfiguration if current lockUntil <= now