internal void Discard()
{
try
{
_persisting = true;
_removedGraphs.Clear();
// Read-Only managers have no persistence
if (_manager.IsReadOnly)
{
return;
}
// No actions mean no persistence necessary
if (_actions.Count == 0)
{
return;
}
// Important - For discard we reverse the list of actions so that we
// rollback the actions in appropriate order
_actions.Reverse();
if (_manager.UpdateSupported)
{
// Persist based on Triple level actions
// First group Triple together based on Graph URI
while (_actions.Count > 0)
{
TripleStorePersistenceAction action = _actions[0];
if (action.IsTripleAction)
{
Queue <TriplePersistenceAction> actions = new Queue <TriplePersistenceAction>();
Uri currUri = _actions[0].TripleAction.Triple.GraphUri;
actions.Enqueue(_actions[0].TripleAction);
_actions.RemoveAt(0);
// Find all the Triple actions related to this Graph up to the next non-Triple action
for (int i = 0; i < _actions.Count && _actions[i].IsTripleAction; i++)
{
if (EqualityHelper.AreUrisEqual(currUri, _actions[i].TripleAction.Triple.GraphUri))
{
actions.Enqueue(_actions[i].TripleAction);
_actions.RemoveAt(i);
i--;
}
}
// Split the Triples for this Graph into batches of adds and deletes to ensure
// accurate persistence of the actions
bool toDelete = false;
List <Triple> batch = new List <Triple>();
while (actions.Count > 0)
{
TriplePersistenceAction next = actions.Dequeue();
if (next.IsDelete != toDelete)
{
if (batch.Count > 0)
{
// Process a batch whenever we find a switch between additions and removals
// This ensures that regardless of the logic in UpdateGraph() we force
// additions and removals to happen in the order we care about
// Important - For discard we flip the actions in order to reverse them
// i.e. additions become removals and vice versa
// Also for discard we only need to alter the in-memory state not actually
// do any persistence since the actions will never have been persisted
if (toDelete)
{
this[currUri].Assert(batch);
}
else
{
this[currUri].Retract(batch);
}
batch.Clear();
}
toDelete = next.IsDelete;
}
batch.Add(next.Triple);
}
// Ensure the final batch (if any) gets processed
if (batch.Count > 0)
{
// Important - For discard we flip the actions in order to reverse them
// i.e. additions become removals and vice versa
// Also for discard we only need to alter the in-memory state not actually
// do any persistence since the actions will never have been persisted
if (toDelete)
{
this[currUri].Assert(batch);
}
else
{
this[currUri].Retract(batch);
}
}
}
else
{
switch (action.GraphAction.Action)
{
case GraphPersistenceActionType.Added:
// Need to remove from being in-memory
Remove(action.GraphAction.Graph.BaseUri);
break;
case GraphPersistenceActionType.Deleted:
// Need to add back into memory
Add(action.GraphAction.Graph, false);
break;
}
_actions.RemoveAt(0);
}
}
}
else
{
// Persist based on Graph level actions
foreach (TripleStorePersistenceAction action in _actions)
{
// Important - For discard we flip the actions in order to reverse them
// i.e. additions become removals and vice versa
if (action.IsGraphAction)
{
if (action.GraphAction.Action == GraphPersistenceActionType.Added)
{
Remove(action.GraphAction.Graph.BaseUri);
}
else if (action.GraphAction.Action == GraphPersistenceActionType.Deleted)
{
Add(action.GraphAction.Graph, false);
}
}
}
}
}
finally
{
_persisting = false;
}
}
internal void Flush()
{
try
{
_persisting = true;
_removedGraphs.Clear();
// Read-Only managers have no persistence
if (_manager.IsReadOnly)
{
return;
}
// No actions means no persistence necessary
if (_actions.Count == 0)
{
return;
}
if (_manager.UpdateSupported)
{
// Persist based on Triple level actions
// First group Triple together based on Graph URI
while (_actions.Count > 0)
{
TripleStorePersistenceAction action = _actions[0];
if (action.IsTripleAction)
{
Queue <TriplePersistenceAction> actions = new Queue <TriplePersistenceAction>();
Uri currUri = action.TripleAction.Triple.GraphUri;
actions.Enqueue(_actions[0].TripleAction);
_actions.RemoveAt(0);
// Find all the Triple actions related to this Graph up to the next non-Triple action
for (int i = 0; i < _actions.Count && _actions[i].IsTripleAction; i++)
{
if (EqualityHelper.AreUrisEqual(currUri, _actions[i].TripleAction.Triple.GraphUri))
{
actions.Enqueue(_actions[i].TripleAction);
_actions.RemoveAt(i);
i--;
}
}
// Split the Triple Actions for this Graph into batches of adds and deletes to ensure
// accurate persistence of the actions
bool toDelete = false;
List <Triple> batch = new List <Triple>();
while (actions.Count > 0)
{
TriplePersistenceAction next = actions.Dequeue();
if (next.IsDelete != toDelete)
{
if (batch.Count > 0)
{
// Process a batch whenever we find a switch between additions and removals
// This ensures that regardless of the logic in UpdateGraph() we force
// additions and removals to happen in the order we care about
if (toDelete)
{
_manager.UpdateGraph(currUri, null, batch);
}
else
{
_manager.UpdateGraph(currUri, batch, null);
}
batch.Clear();
}
toDelete = next.IsDelete;
}
batch.Add(next.Triple);
}
// Ensure the final batch (if any) gets processed
if (batch.Count > 0)
{
if (toDelete)
{
_manager.UpdateGraph(currUri, null, batch);
}
else
{
_manager.UpdateGraph(currUri, batch, null);
}
}
}
else
{
switch (action.GraphAction.Action)
{
case GraphPersistenceActionType.Added:
// No need to do anything in-memory as will be in the graph collection
// Call SaveGraph() with an empty graph to create the relevant graph
// If Triples were added these will be persisted separately with
// TriplePersistenceActions
Graph g = new Graph();
g.BaseUri = action.GraphAction.Graph.BaseUri;
_manager.SaveGraph(g);
break;
case GraphPersistenceActionType.Deleted:
// No need to do anything in-memory as won't be in the graph collection
// If DeleteGraph() is supported call it to delete the relevant graph
if (_manager.DeleteSupported)
{
_manager.DeleteGraph(action.GraphAction.Graph.BaseUri);
}
break;
}
_actions.RemoveAt(0);
}
}
}
else
{
// Persist based on Graph level actions
foreach (TripleStorePersistenceAction action in _actions)
{
if (action.IsGraphAction)
{
if (action.GraphAction.Action == GraphPersistenceActionType.Added)
{
_manager.SaveGraph(action.GraphAction.Graph);
}
else if (action.GraphAction.Action == GraphPersistenceActionType.Deleted && _manager.DeleteSupported)
{
// Can only delete graphs if deletion is supported
_manager.DeleteGraph(action.GraphAction.Graph.BaseUri);
}
}
}
}
}
finally
{
_persisting = false;
}
}
