org.datanucleus.store.types.queued
Class SCOOperationQueue

java.lang.Object
  org.datanucleus.store.types.queued.SCOOperationQueue

public class SCOOperationQueue
extends Object

Queue of operations to be performed on second class collections/maps. When we are queueing operations until flush()/commit() they wait in this queue until the moment arrives for flushing to the datastore (and

performAll

is called). Note that this queue will contain all operations to be performed for an ExecutionContext, though currently (DN v3.2) will process them backing store by backing store, rather than in the order they necessarily came in.

Field Summary

protected static Localiser	LOCALISER
protected List<QueuedOperation>	queuedOperations

Constructor Summary

SCOOperationQueue()

Method Summary

void	clear()
void	enqueue(QueuedOperation oper) Method to add the specified operation to the operation queue.
List<QueuedOperation>	getOperations() Method to provide access to inspect the queued operations.
protected static boolean	isAddFollowedByRemoveOnSameSCO(Store store, ObjectProvider op, QueuedOperation currentOper, ListIterator<QueuedOperation> 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, QueuedOperation currentOper, ListIterator<QueuedOperation> 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, QueuedOperation currentOper, ListIterator<QueuedOperation> listIter) Convenience optimisation checker to return if the current operation is REMOVE of an element that is immediately ADDed.
void	performAll(Store store, ObjectProvider op) Method to perform all operations queued for the specified ObjectProvider and backing store.

Methods inherited from class java.lang.Object

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

Field Detail

LOCALISER

protected static final Localiser LOCALISER

queuedOperations

protected List<QueuedOperation> queuedOperations

Constructor Detail

SCOOperationQueue

public SCOOperationQueue()

Method Detail

enqueue

public void enqueue(QueuedOperation oper)

Method to add the specified operation to the operation queue.

Parameters:

oper - Operation

clear

public void clear()

getOperations

public List<QueuedOperation> getOperations()

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

Returns:

The queued operations

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

isAddFollowedByRemoveOnSameSCO

protected static boolean isAddFollowedByRemoveOnSameSCO(Store store,
                                                        ObjectProvider op,
                                                        QueuedOperation currentOper,
                                                        ListIterator<QueuedOperation> 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,
                                                        QueuedOperation currentOper,
                                                        ListIterator<QueuedOperation> 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,
                                                        QueuedOperation currentOper,
                                                        ListIterator<QueuedOperation> 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