org.datanucleus.flush

Class OperationQueue

java.lang.Object

org.datanucleus.flush.OperationQueue

public class OperationQueue
extends Object

Queue of operations to be performed when operating in MANUAL FlushMode. This queue will typically contain operations on second class objects, such as Collections or Maps. They are queued in the order they are invoked by the user. The queue will contain all operations to be performed for an ExecutionContext. There are two methods for processing them, one processing all (for use in the future when we support that mode in full), and one that processes all for a particular SCO (backing store).

Field Summary

Fields

Modifier and Type	Field and Description
protected List<Operation>	queuedOperations

Constructor Summary

Constructors

Constructor and Description
OperationQueue()

Method Summary

Modifier and Type	Method and Description
void	clear()
void	clearPersistDeleteUpdateOperations()
void	enqueue(Operation oper) Method to add the specified operation to the operation queue.
List<Operation>	getOperations() Method to provide access to inspect the queued operations.
protected static boolean	isAddFollowedByRemoveOnSameSCO(Store store, ObjectProvider op, Operation currentOper, ListIterator<Operation> listIter) Convenience optimisation checker to return if the current operation is ADD of an element that is immediately REMOVED.
protected static boolean	isPutFollowedByRemoveOnSameSCO(Store store, ObjectProvider op, Operation currentOper, ListIterator<Operation> listIter) Convenience optimisation checker to return if the current operation is PUT of a key that is immediately REMOVED.
protected static boolean	isRemoveFollowedByAddOnSameSCO(Store store, ObjectProvider op, Operation currentOper, ListIterator<Operation> listIter) Convenience optimisation checker to return if the current operation is REMOVE of an element that is immediately ADDed.
void	log() Convenience method to log the current operation queue.
void	performAll() Method to perform all operations queued.
void	performAll(Store store, ObjectProvider op) Method to perform all operations queued for the specified ObjectProvider and backing store.
void	processOperationsForNoBackingStoreSCOs(ExecutionContext ec) Method to process all SCO operations where the SCOs don't use a backing store.
void	removeOperations(List<Operation> removedOps)

Methods inherited from class java.lang.Object

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

Field Detail

queuedOperations

protected List<Operation> queuedOperations

Constructor Detail

OperationQueue

public OperationQueue()

Method Detail

enqueue

public void enqueue(Operation oper)

Method to add the specified operation to the operation queue.

Parameters:

oper - Operation

log

public void log()

Convenience method to log the current operation queue.

clear

public void clear()

getOperations

public List<Operation> getOperations()

Method to provide access to inspect the queued operations. The returned list is unmodifiable.

Returns:

The queued operations

removeOperations

public void removeOperations(List<Operation> removedOps)

performAll

public void performAll()

Method to perform all operations queued. Those operations are then removed from the queue.

performAll

public void performAll(Store store,
                       ObjectProvider op)

Method to perform all operations queued for the specified ObjectProvider and backing store. Those operations are then removed from the queue.

Parameters:

store - The backing store

op - ObjectProvider

clearPersistDeleteUpdateOperations

public void clearPersistDeleteUpdateOperations()

processOperationsForNoBackingStoreSCOs

public void processOperationsForNoBackingStoreSCOs(ExecutionContext ec)

Method to process all SCO operations where the SCOs don't use a backing store. This will check for add+remove/remove+add and perform cascade delete as appropriate. It will then remove the SCO operations from the queue. It doesn't actually process the queued operations since when you have no backing store there is nothing to do.

Parameters:

ec - ExecutionContext

isAddFollowedByRemoveOnSameSCO

protected static boolean isAddFollowedByRemoveOnSameSCO(Store store,
                                                        ObjectProvider op,
                                                        Operation currentOper,
                                                        ListIterator<Operation> listIter)

Convenience optimisation checker to return if the current operation is ADD of an element that is immediately REMOVED. Always leaves the iterator at the same position as starting

Parameters:

store - The backing store

op - The object provider

currentOper - The current operation

listIter - The iterator of operations

Returns:

Whether this is an ADD that has a REMOVE of the same element immediately after

isRemoveFollowedByAddOnSameSCO

protected static boolean isRemoveFollowedByAddOnSameSCO(Store store,
                                                        ObjectProvider op,
                                                        Operation currentOper,
                                                        ListIterator<Operation> listIter)

Convenience optimisation checker to return if the current operation is REMOVE of an element that is immediately ADDed. Always leaves the iterator at the same position as starting

Parameters:

store - The backing store

op - The object provider

currentOper - The current operation

listIter - The iterator of operations

Returns:

Whether this is a REMOVE that has an ADD of the same element immediately after

isPutFollowedByRemoveOnSameSCO

protected static boolean isPutFollowedByRemoveOnSameSCO(Store store,
                                                        ObjectProvider op,
                                                        Operation currentOper,
                                                        ListIterator<Operation> listIter)

Convenience optimisation checker to return if the current operation is PUT of a key that is immediately REMOVED. Always leaves the iterator at the same position as starting

Parameters:

store - The backing store

op - The object provider

currentOper - The current operation

listIter - The iterator of operations

Returns:

Whether this is a PUT that has a REMOVE of the same key immediately after