Objects of this class monitor the lock state of persistent objects. More...

#include <GloLockManager.h>

Classes
class	LockedObject
	Objects can be locked. Objects of this class represent an object locked by the communicator, with possibly also locked objects like embedded objects. More...

Public Member Functions
	LockManager (Manager *pDBManager)

virtual	~LockManager ()

void	deleteAllLocks (Communicator *pCommunicator, const std::string &rsSchemaName)

void	getNotAllowedReadObjects (std::list< ObjID > &rReadLockObjList, const TransactionOwner &rCommunicatorWithTreadID) const

LockPossibleSpecification	getProcessingPossibilities (const ObjID &rObjID, std::map< ObjID, Record *, std::less< ObjID > > &rDependObjects, const TransactionOwner &rCommunicatorWithTreadID)

bool	isPossible (const ObjID &rObjID, std::map< ObjID, Record *, std::less< ObjID > > &rDependObjects, const TransactionOwner &rCommunicatorWithTreadID, bool bRead, bool bWrite, bool bDelete)

int	lockObject (const ObjID &rObjID, std::map< ObjID, Record *, std::less< ObjID > > &rDependObjects, const TransactionOwner &rCommunicatorWithTreadID, const std::string &rsSchemaName, EnLockMode eLockMode, EnDeepMode eDeepMode, bool bSimulate=false)

int	unlockObject (const ObjID &rObjID, const TransactionOwner &rCommunicatorWithTreadID, const std::string &rsSchemaName, EnLockMode eLockMode, EnDeepMode eDeepMode, bool bSimulate=false)

Protected Member Functions
	LockManager ()

Private Member Functions
	LockManager (const LockManager &)

LockManager &	operator= (const LockManager &)

void	sendNotify (TdWatchNotifyMode nWatchNotifyMode, const ObjID &rObjID, Communicator *pCommunicator, const std::string &rsSchemaName)

Private Attributes
std::unordered_map< unsigned long, LockedObject * >	m_LockedObjectMap

Manager *	m_pDBManager

Detailed Description

Objects of this class monitor the lock state of persistent objects.

No lock states are stored in the tables. The Manager must register objects for locking (with the locking or releasing communicator) and always ask before actions whether they are allowed. Lock states of single objects can be requested.

Since an object should be able to be locked e.g. with its dependent objects, objects are passed with their dependent objects to lock. The lock possibility of each object is checked and if possible all objects are locked with passed lock mode or none.

For each lock mode there is a list in which the list of dependent objects with the lock depth mode is stored.

When an object is released with a specific lock mode and lock depth mode, the list is removed from the lock mode list and any objects contained are also released with the same lock mode.

This is necessary because, for example, an object 'A' can be locked with a referenced object 'B'. The application can now dereference the referenced object 'B' into object 'A'. When object 'A' is released, the previously referenced object 'B' is no longer linked to object 'A' and would therefore not be released.

The following table lists the individual lock modes and their effects.

The following abbreviations apply to the lock modes:

The following abbreviations apply to actions:

R -> Read
W -> Write
D -> Delete

Blocking modes and their effects
Locking instance			Other instances
Lock mode	Guarantee to do...	Protect from...	Allowed lock modes	Possibilities	Restrictions
NN	none	none	all	all	none
RD	R	D	RD, RW, WW, TW	R, W	D
RW	R	D, W	RD, RW	R	D, W
WW	R, W	D, W	RD	R	D, W
DW	R, W, D	D, W	none	R	D, W
DR	R, W, D	D, W, R	none	none	D, R, W
EX	R, W, D	D, W, R	none	none	D, R, W
TW	R, W	D, W	RD	R	D, W
TD	R, W, D	D, W	none	R	D, W

The structure of the LockManager looks like this:

Copyright: © 2010 Helmut Jakoby

Author: Helmut Jakoby

Constructor & Destructor Documentation

◆ LockManager() [1/3]

glo::LockManager::LockManager ( )

protected

The default constructor is not available.

◆ LockManager() [2/3]

glo::LockManager::LockManager ( Manager * pDBManager )

Constructor with parameter passing.

Parameters

[in] pDBManager Backreference to the owning Manager, must not be removed from memory during the lifetime of this object.

◆ ~LockManager()

virtual glo::LockManager::~LockManager ( )

virtual

Destructor, cleaning up.

◆ LockManager() [3/3]

glo::LockManager::LockManager ( const LockManager & )

private

The copy constructor is not available.

Member Function Documentation

◆ deleteAllLocks()

void glo::LockManager::deleteAllLocks	(	Communicator *	pCommunicator,
		const std::string &	rsSchemaName )

All locks of the passed communicator are removed.

Parameters

[in]	pCommunicator	The communicator.
[in]	rsSchemaName	The schema name is used for notification.

◆ getNotAllowedReadObjects()

void glo::LockManager::getNotAllowedReadObjects	(	std::list< ObjID > &	rReadLockObjList,
		const TransactionOwner &	rCommunicatorWithTreadID ) const

Returns all object IDs of the read-only objects for the passed communicator.

Parameters

[in,out]	rReadLockObjList	The object IDs of the read locked objects.
[in]	rCommunicatorWithTreadID	The communicator with thread-id.

◆ getProcessingPossibilities()

LockPossibleSpecification glo::LockManager::getProcessingPossibilities	(	const ObjID &	rObjID,
		std::map< ObjID, Record *, std::less< ObjID > > &	rDependObjects,
		const TransactionOwner &	rCommunicatorWithTreadID )

Returns the possible action with an object for a communicator.

Parameters

[in]	rObjID	The object ID to be checked.
[in]	rDependObjects	The map of data sets of the objects to be checked.
[in]	rCommunicatorWithTreadID	The communicator with thread-id.

Returns: The possibilities in a LockPossibleSpecification.

◆ isPossible()

bool glo::LockManager::isPossible	(	const ObjID &	rObjID,
		std::map< ObjID, Record *, std::less< ObjID > > &	rDependObjects,
		const TransactionOwner &	rCommunicatorWithTreadID,
		bool	bRead,
		bool	bWrite,
		bool	bDelete )

Checks whether the transferred communicator is allowed to read, write and/or delete the object with transferred object ID.

Parameters

[in]	rObjID	The object ID to be checked.
[in]	rDependObjects	The map of data sets of the objects to be checked.
[in]	rCommunicatorWithTreadID	The communicator with thread-id.
[in]	bRead	If true, a 'read' check is performed.
[in]	bWrite	If true, a 'write' check is performed.
[in]	bDelete	If true, checks for 'delete'.

Returns: If true, the true set modes are possible for the communicator.

◆ lockObject()

int glo::LockManager::lockObject	(	const ObjID &	rObjID,
		std::map< ObjID, Record *, std::less< ObjID > > &	rDependObjects,
		const TransactionOwner &	rCommunicatorWithTreadID,
		const std::string &	rsSchemaName,
		EnLockMode	eLockMode,
		EnDeepMode	eDeepMode,
		bool	bSimulate = false )

Locks an object with passed object ID for a communicator.

Parameters

[in]	rObjID	The object ID of the object to be locked.
[in]	rDependObjects	The map of records of the objects to be locked.
[in]	rCommunicatorWithTreadID	The locking communicator with thread-id.
[in]	rsSchemaName	The schema name is used for notification.
[in]	eLockMode	The locking mode.
[in]	eDeepMode	The lock depth mode.
[in]	bSimulate	If true, only simulation is used, no value is set, but a valid result or error is returned.

Returns: A return value < 0 indicates an error.

◆ operator=()

LockManager & glo::LockManager::operator= ( const LockManager & )

private

The assignment operator is not available.

◆ sendNotify()

void glo::LockManager::sendNotify	(	TdWatchNotifyMode	nWatchNotifyMode,
		const ObjID &	rObjID,
		Communicator *	pCommunicator,
		const std::string &	rsSchemaName )

private

Initiates a Notify via its m_pDBManager.

Parameters

[in]	nWatchNotifyMode	The watch mode.
[in]	rObjID	The Object-ID of the affected object.
[in]	pCommunicator	The communicator.
[in]	rsSchemaName	The schema name is used for notification.

◆ unlockObject()

int glo::LockManager::unlockObject	(	const ObjID &	rObjID,
		const TransactionOwner &	rCommunicatorWithTreadID,
		const std::string &	rsSchemaName,
		EnLockMode	eLockMode,
		EnDeepMode	eDeepMode,
		bool	bSimulate = false )

Releases the object locked by a communicator with passed object ID.

Parameters

[in]	rObjID	The object ID of the object to be released.
[in]	rCommunicatorWithTreadID	The releasing communicator with thread-id.
[in]	rsSchemaName	The schema name is used for notification.
[in]	eLockMode	The locking mode.
[in]	eDeepMode	The lock depth mode.
[in]	bSimulate	If true, only simulation is used, no value is set, but a valid result or error is returned.

Returns: A return value < 0 indicates an error.

Member Data Documentation

◆ m_LockedObjectMap

std::unordered_map< unsigned long, LockedObject * > glo::LockManager::m_LockedObjectMap

private

List of the locked objects.

◆ m_pDBManager

Manager* glo::LockManager::m_pDBManager

private

Back reference to the owning Manager.

The documentation for this class was generated from the following file:

GloLockManager.h

Classes

Public Member Functions

Protected Member Functions

Private Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ LockManager() [1/3]

◆ LockManager() [2/3]

◆ ~LockManager()

◆ LockManager() [3/3]

Member Function Documentation

◆ deleteAllLocks()

◆ getNotAllowedReadObjects()

◆ getProcessingPossibilities()

◆ isPossible()

◆ lockObject()

◆ operator=()

◆ sendNotify()

◆ unlockObject()

Member Data Documentation

◆ m_LockedObjectMap

◆ m_pDBManager