class to guarantee transactions. More...

#include <GloTransactionManager.h>

Classes
class	CommunicatorTransactionStack
	The transaction stack of a client communicator for a database. More...

class	TransactionBase
	Base class for TransactionPoint and TransactionStep. More...

class	TransactionPoint
	Objects of this class reflect a transaction start. More...

class	TransactionStep
	Objects of this class reflect a record operation. More...

Public Types
enum	EnStoreDelete { eTRX_STORE , eTRX_DELETE }

Public Member Functions
	TransactionManager ()

virtual	~TransactionManager ()

int	abortTransaction (std::list< TransactionBase * > &rAbortedTransactionStepList, Communicator *pCommunicator)

void	beginTransaction (Communicator *pCommunicator)

int	commitTransaction (CommunicatorTransactionStack &prRetVal, Communicator pCommunicator)

void	deleteTransaction (Communicator *pCommunicator)

int	getActionRecord (Record &prRetVal, EnStoreDelete &reAction, Communicator pCommunicator, const ObjID &rObjID, const std::string &rsDataPath, bool bInRecursion=false)

bool	inTransaction (Communicator *pCommunicator) const

int	setTransactionStep (NUM_PTR &nNewTrxStepAddr, Communicator pCommunicator, EnStoreDelete eAction, Record pActionRecord)

Protected Member Functions
TransactionManager::CommunicatorTransactionStack *	getTransactionStack (Communicator *pCommunicator)

void	removeCurrentTransactionStack ()

Private Member Functions
	TransactionManager (const TransactionManager &)

TransactionManager &	operator= (const TransactionManager &)

int	writeTransactionFile (CommunicatorTransactionStack *pTransactionStack)

Private Attributes
std::map< ObjID, Record *, std::less< ObjID > >	m_RecursionRecordMap

std::map< NUM_PTR, CommunicatorTransactionStack *, std::less< NUM_PTR > >	m_TransactionStackMap

std::map< NUM_PTR, CommunicatorTransactionStack * >::iterator	m_TransactionStackMapIterator

Detailed Description

class to guarantee transactions.

Objects of this class are instantiated and managed by the Manager.

Each database operation (save and delete) is packed into a transaction and passed to the Transaction Manager (e.g. action with the dependent objects).

The process looks like this: The transaction start (TransactionPoint) is placed on the transaction stack of the requesting instance and a transaction counter is incremented (set to 1 the first time).

Then each record operation (TransactionStep) is placed on the transaction stack. The TransactionStep contains the record as it looks like before the action and as it looks like after the respective action (e.g. saved or deleted).

If a new TransactionStart (TransactionPoint) is added, it is also placed on the transaction stack and the transaction counter is incremented again.

If a transaction abort (TransactionPoint) is added, the transaction stack is reduced until the last transaction start (TransactionPoint) and the transaction counter is decremented. When the first transaction start (TransactionPoint) is reached, the transaction is discarded.

If a transaction commit is placed on the transaction stack, the transaction counter is decremented (if 0, everything on the transaction stack is executed).

All accesses of a requesting instance to data to be made by the TableReaderInterface are first sent to the TransactionManager. If the TransactionManager holds the requested data records (see above, the data records after the action triggered by the requesting instance), these are delivered first. The rest is read directly from the tables by the TableReaderInterface.

Future: Execute means that a transaction file is written which is interpreted by the Manager (all actions sent to the TableWriterInterface). If everything has been processed by the TableWriterInterface, the transaction file will be deleted, otherwise not. For example, if the Manager crashes with an exception, the transaction file still exists if the transaction is not completed. In case of a restart, the system always tries to process an existing transaction file first.

Copyright: © 2010 Helmut Jakoby

Author: Helmut Jakoby

Member Enumeration Documentation

◆ EnStoreDelete

enum glo::TransactionManager::EnStoreDelete

Internally, which action should be executed.

Enumerator
eTRX_STORE	It should be stored.
eTRX_DELETE	It should be deleted.

Constructor & Destructor Documentation

◆ TransactionManager() [1/2]

glo::TransactionManager::TransactionManager ( )

Standard onstructor.

◆ ~TransactionManager()

virtual glo::TransactionManager::~TransactionManager ( )

virtual

Destructor.

◆ TransactionManager() [2/2]

glo::TransactionManager::TransactionManager ( const TransactionManager & )

private

The copy constructor is not available.

Member Function Documentation

◆ abortTransaction()

int glo::TransactionManager::abortTransaction	(	std::list< TransactionBase * > &	rAbortedTransactionStepList,
		Communicator *	pCommunicator )

The current transaction is cancelled.

Parameters

[in,out]	rAbortedTransactionStepList	In this list the rejected TransactionSteps are delivered (must be amongst other things released in the LockManager).
[in]	pCommunicator	The client communicator that aborts the transaction.

Returns: A return < 0 indicates an error.

Attention: The objects in the returned list must be removed from memory by the calling instance.

◆ beginTransaction()

void glo::TransactionManager::beginTransaction ( Communicator * pCommunicator )

Starts a new transaction by placing a new TransactionPoint on the transaction stack.

Parameters

[in] pCommunicator The client communicator that starts the transaction.

Exceptions

eut::ErrorNException An exception is thrown if an error occurs.

◆ commitTransaction()

int glo::TransactionManager::commitTransaction	(	CommunicatorTransactionStack *&	prRetVal,
		Communicator *	pCommunicator )

Current transaction is accepted.

Parameters

[in,out]	prRetVal	If return > 0, then the transaction stack of the client communicator is delivered to perform the steps.
[in]	pCommunicator	The client communicator that commits the transaction.

Returns: A return > 0 indicates that the delivered transaction stack can be processed.
A return == 0 indicates that within a nested transaction has been accepted.
A return value < 0 indicates an error.

Attention: The returned object must be removed from memory by the calling instance.

◆ deleteTransaction()

void glo::TransactionManager::deleteTransaction ( Communicator * pCommunicator )

One, possibly existing, transaction of the passed client communicator is removed.

Parameters

[in] pCommunicator The client communicator.

◆ getActionRecord()

int glo::TransactionManager::getActionRecord	(	Record *&	prRetVal,
		EnStoreDelete &	reAction,
		Communicator *	pCommunicator,
		const ObjID &	rObjID,
		const std::string &	rsDataPath,
		bool	bInRecursion = false )

Returns the last data record appended in the transaction stack including the database action with the passed object ID and the client communicator.

Parameters

[in,out]	prRetVal	The record, if available.
[in,out]	reAction	The action how the record should be handled; save or delete.
[in]	pCommunicator	The client communicator that wanted to edit the record in a transaction.
[in]	rObjID	The object ID of the desired record.
[in]	rsDataPath	The file path to retrieve the object IDs from files, if necessary.
[in]	bInRecursion	If true, then call in itself.

Returns: A return value < 0 indicates an error.

Attention: The calling instance must remove the possibly supplied record from memory with Record::forget().

Note: For Glo developers: Is implemented in GloRecordAttributeFunctions.cpp, so that extensions of data set attributes can be made there collectively.

◆ getTransactionStack()

TransactionManager::CommunicatorTransactionStack * glo::TransactionManager::getTransactionStack ( Communicator * pCommunicator )

protected

Returns a pointer to the transaction stack of the passed client communicator.

Parameters

[in] pCommunicator The client communicator.

Returns: The pointer to an existing transaction stack, if any. If the client communicator has no transaction running, the return value is == NULL_PTR.

◆ inTransaction()

bool glo::TransactionManager::inTransaction ( Communicator * pCommunicator ) const

Checks if passed client communicator has a transaction running.

Parameters

[in] pCommunicator The client communicator.

Returns: If true, the passed client communicator has a transaction running.

◆ operator=()

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

private

The assignment operator is not available.

◆ removeCurrentTransactionStack()

void glo::TransactionManager::removeCurrentTransactionStack ( )

protected

Removes the current transaction stack. If there is a subsequent tramsaction, it becomes the current transaction in the m_TransactionStackMap.

◆ setTransactionStep()

int glo::TransactionManager::setTransactionStep	(	NUM_PTR &	nNewTrxStepAddr,
		Communicator *	pCommunicator,
		EnStoreDelete	eAction,
		Record *	pActionRecord )

Generates a TransactionStep and places it on the transaction stack.

Parameters

[in,out]	nNewTrxStepAddr	The address of the created TransactionStep to manage indexes (see also IndexPool::ObjectStrIndex::m_ReservedIndexMultiMap).
[in]	pCommunicator	The client communicator that aborts the transaction.
[in]	eAction	The action how to handle the record; save or delete.
[in]	pActionRecord	The record to be saved or deleted. The record is copied and not 'remembert'.

Returns: A return value < 0 indicates an error.

◆ writeTransactionFile()

int glo::TransactionManager::writeTransactionFile ( CommunicatorTransactionStack * pTransactionStack )

private

Not yet implemented!

Member Data Documentation

◆ m_RecursionRecordMap

std::map< ObjID, Record *, std::less<ObjID> > glo::TransactionManager::m_RecursionRecordMap

private

If records are read recursively, the already read records come in here.

◆ m_TransactionStackMap

std::map< NUM_PTR, CommunicatorTransactionStack *, std::less<NUM_PTR> > glo::TransactionManager::m_TransactionStackMap

private

A map with the transactions. Key is the address of the Communicator for which a transaction has been created, casted to NUM_PTR.

◆ m_TransactionStackMapIterator

std::map<NUM_PTR,CommunicatorTransactionStack*>::iterator glo::TransactionManager::m_TransactionStackMapIterator

private

An internal iterator on the map with the transactions (m_TransactionStackMap).

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

GloTransactionManager.h

Classes

Public Types

Public Member Functions

Protected Member Functions

Private Member Functions

Private Attributes

Detailed Description

Member Enumeration Documentation

◆ EnStoreDelete

Constructor & Destructor Documentation

◆ TransactionManager() [1/2]

◆ ~TransactionManager()

◆ TransactionManager() [2/2]

Member Function Documentation

◆ abortTransaction()

◆ beginTransaction()

◆ commitTransaction()

◆ deleteTransaction()

◆ getActionRecord()

◆ getTransactionStack()

◆ inTransaction()

◆ operator=()

◆ removeCurrentTransactionStack()

◆ setTransactionStep()

◆ writeTransactionFile()

Member Data Documentation

◆ m_RecursionRecordMap

◆ m_TransactionStackMap

◆ m_TransactionStackMapIterator