Package org.datanucleus.state

Class LockManagerImpl

java.lang.Object

org.datanucleus.state.LockManagerImpl

All Implemented Interfaces:

LockManager

public class LockManagerImpl
extends Object
implements LockManager

Implementation of a lock manager for objects.

Constructor Summary

Constructors

Constructor	Description
LockManagerImpl(ExecutionContext ec)

Method Summary

Modifier and Type	Method	Description
void	clear()	Method to clear all settings of required lock level.
void	close()	Method to close the manager and release resources.
LockMode	getLockMode(Object id)	Accessor for what locking should be applied to the object with the specified identity (mode 2).
LockMode	getLockMode(DNStateManager sm)	Accessor for the current lock mode for the object managed by the passed StateManager (mode 1).
Object	getNextVersion(VersionMetaData vermd, Object currentVersion)	Convenience method to provide the next version to use given the VersionMetaData and the current version.
void	lock(Object id, LockMode lockMode)	Method to lock the object with the provided identity (mode 2).
void	lock(DNStateManager sm, LockMode lockMode)	Method to lock the object managed by the passed StateManager (mode 1).
void	performOptimisticVersionCheck(DNStateManager sm, VersionStrategy versionStrategy, Object versionDatastore)	Perform an optimistic version check on the passed object, against the passed version in the datastore.
void	unlock(DNStateManager sm)	Method to unlock the object managed by the passed StateManager (mode 1).

Methods inherited from class java.lang.Object

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

Constructor Detail

LockManagerImpl

public LockManagerImpl(ExecutionContext ec)

Method Detail

close

public void close()

Description copied from interface: LockManager

Method to close the manager and release resources.

Specified by:

close in interface LockManager

clear

public void clear()

Description copied from interface: LockManager

Method to clear all settings of required lock level.

Specified by:

clear in interface LockManager

lock

public void lock(Object id,
                 LockMode lockMode)

Description copied from interface: LockManager

Method to lock the object with the provided identity (mode 2).

Specified by:

lock in interface LockManager

Parameters:

id - Identity of the object

lockMode - mode for locking

getLockMode

public LockMode getLockMode(Object id)

Description copied from interface: LockManager

Accessor for what locking should be applied to the object with the specified identity (mode 2).

Specified by:

getLockMode in interface LockManager

Parameters:

id - The identity

Returns:

The lock mode to apply (NONE if nothing defined)

lock

public void lock(DNStateManager sm,
                 LockMode lockMode)

Description copied from interface: LockManager

Method to lock the object managed by the passed StateManager (mode 1).

Specified by:

lock in interface LockManager

Parameters:

sm - StateManager for the object

lockMode - mode for locking

unlock

public void unlock(DNStateManager sm)

Description copied from interface: LockManager

Method to unlock the object managed by the passed StateManager (mode 1).

Specified by:

unlock in interface LockManager

Parameters:

sm - StateManager for the object

getLockMode

public LockMode getLockMode(DNStateManager sm)

Description copied from interface: LockManager

Accessor for the current lock mode for the object managed by the passed StateManager (mode 1).

Specified by:

getLockMode in interface LockManager

Parameters:

sm - StateManager for the object

Returns:

The lock mode

performOptimisticVersionCheck

public void performOptimisticVersionCheck(DNStateManager sm,
                                          VersionStrategy versionStrategy,
                                          Object versionDatastore)

Perform an optimistic version check on the passed object, against the passed version in the datastore.

Specified by:

performOptimisticVersionCheck in interface LockManager

Parameters:

sm - StateManager of the object to check

versionStrategy - Version strategy

versionDatastore - Version of the object in the datastore

Throws:

NucleusUserException - thrown when an invalid strategy is specified

NucleusOptimisticException - thrown when the version check fails

getNextVersion

public Object getNextVersion(VersionMetaData vermd,
                             Object currentVersion)

Convenience method to provide the next version to use given the VersionMetaData and the current version.

Specified by:

getNextVersion in interface LockManager

Parameters:

currentVersion - The current version

vermd - Version metadata

Returns:

The next version

Throws:

NucleusUserException - Thrown if the strategy is not supported.