/// <summary>
/// Decides which check connectedness operations are needed for the given edge in both directions
/// and inserts them into the search program
/// returns new insertion point and continuation point
/// for continuing buildup after the stuff nested within both directions iteration was built
/// todo: if no direction iteration was needed, insertion point == continuation point ?
/// </summary>
private SearchProgramOperation decideOnAndInsertCheckConnectednessOfEdgeBothDirections(
SearchProgramOperation insertionPoint,
SearchPlanEdgeNode edge,
bool edgeDeterminationContainsFirstNodeLoop,
out SearchProgramOperation continuationPoint)
{
continuationPoint = null;
// check whether source/target-nodes of the candidate edge
// are the same as the already found nodes to which the edge must be incident
if (!edgeDeterminationContainsFirstNodeLoop && currentEdgeConnectsToFirstIncidentNode(edge))
{
// due to currentEdgeConnectsToFirstIncidentNode: at least on incident node available
if (edge.PatternEdgeSource == edge.PatternEdgeTarget)
{
// reflexive edge without direction iteration as we don't want 2 matches
SearchPlanNodeNode nodeRequiringFirstNodeLoop = edge.PatternEdgeSource != null ?
edge.PatternEdgeSource : edge.PatternEdgeTarget;
CheckCandidateForConnectedness checkConnectedness =
new CheckCandidateForConnectedness(
edge.PatternElement.Name,
nodeRequiringFirstNodeLoop.PatternElement.Name,
edge.PatternElement.Name,
CheckCandidateForConnectednessType.Source); // might be Target as well
insertionPoint = insertionPoint.Append(checkConnectedness);
}
else
{
BothDirectionsIteration directionsIteration =
new BothDirectionsIteration(edge.PatternElement.Name);
directionsIteration.NestedOperationsList = new SearchProgramList(directionsIteration);
continuationPoint = insertionPoint.Append(directionsIteration);
insertionPoint = directionsIteration.NestedOperationsList;
SearchPlanNodeNode nodeRequiringFirstNodeLoop = edge.PatternEdgeSource != null ?
edge.PatternEdgeSource : edge.PatternEdgeTarget;
CheckCandidateForConnectedness checkConnectedness =
new CheckCandidateForConnectedness(
edge.PatternElement.Name,
nodeRequiringFirstNodeLoop.PatternElement.Name,
edge.PatternElement.Name,
CheckCandidateForConnectednessType.SourceOrTarget);
insertionPoint = insertionPoint.Append(checkConnectedness);
}
}
if (currentEdgeConnectsToSecondIncidentNode(edge))
{
// due to currentEdgeConnectsToSecondIncidentNode: both incident node available
CheckCandidateForConnectedness checkConnectedness =
new CheckCandidateForConnectedness(
edge.PatternElement.Name,
edge.PatternEdgeTarget.PatternElement.Name,
edge.PatternElement.Name,
edge.PatternEdgeSource.PatternElement.Name,
CheckCandidateForConnectednessType.TheOther);
insertionPoint = insertionPoint.Append(checkConnectedness);
}
return insertionPoint;
}
/// <summary>
/// Decides which check connectedness operations are needed for the given node and edge in both directions
/// and inserts them into the search program
/// returns new insertion point and continuation point
/// for continuing buildup after the stuff nested within both directions iteration was built
/// if no direction iteration was needed, insertion point == continuation point
/// </summary>
private SearchProgramOperation decideOnAndInsertCheckConnectednessOfNodeBothDirections(
SearchProgramOperation insertionPoint,
SearchPlanNodeNode currentNode,
SearchPlanEdgeNode edge,
out SearchProgramOperation continuationPoint)
{
Debug.Assert(edge.PatternEdgeSource != edge.PatternEdgeTarget);
continuationPoint = null;
// check whether the pattern edges which must be incident to the candidate node (according to the pattern)
// are really incident to it
if (currentNodeIsFirstIncidentNodeOfEdge(currentNode, edge))
{
BothDirectionsIteration directionsIteration =
new BothDirectionsIteration(edge.PatternElement.Name);
directionsIteration.NestedOperationsList = new SearchProgramList(directionsIteration);
continuationPoint = insertionPoint.Append(directionsIteration);
CheckCandidateForConnectedness checkConnectedness =
new CheckCandidateForConnectedness(
currentNode.PatternElement.Name,
currentNode.PatternElement.Name,
edge.PatternElement.Name,
CheckCandidateForConnectednessType.SourceOrTarget);
insertionPoint = directionsIteration.NestedOperationsList.Append(checkConnectedness);
}
if (currentNodeIsSecondIncidentNodeOfEdge(currentNode, edge))
{
CheckCandidateForConnectedness checkConnectedness =
new CheckCandidateForConnectedness(
currentNode.PatternElement.Name,
currentNode.PatternElement.Name,
edge.PatternElement.Name,
edge.PatternEdgeSource == currentNode ? edge.PatternEdgeTarget.PatternElement.Name
: edge.PatternEdgeSource.PatternElement.Name,
CheckCandidateForConnectednessType.TheOther);
insertionPoint = insertionPoint.Append(checkConnectedness);
}
if (continuationPoint == null)
continuationPoint = insertionPoint;
return insertionPoint;
}
/// <summary>
/// Decides which check connectedness operations are needed for the given edge of fixed direction
/// and inserts them into the search program
/// </summary>
private SearchProgramOperation decideOnAndInsertCheckConnectednessOfEdgeFixedDirection(
SearchProgramOperation insertionPoint,
SearchPlanEdgeNode edge,
CheckCandidateForConnectednessType connectednessType)
{
// check whether source/target-nodes of the candidate edge
// are the same as the already found nodes to which the edge must be incident
// don't need to, if that node is not matched by now (signaled by visited)
SearchPlanNodeNode nodeRequiringCheck =
connectednessType == CheckCandidateForConnectednessType.Source ?
edge.PatternEdgeSource : edge.PatternEdgeTarget;
if (nodeRequiringCheck.Visited)
{
CheckCandidateForConnectedness checkConnectedness =
new CheckCandidateForConnectedness(
edge.PatternElement.Name,
nodeRequiringCheck.PatternElement.Name,
edge.PatternElement.Name,
connectednessType);
insertionPoint = insertionPoint.Append(checkConnectedness);
}
return insertionPoint;
}
/// <summary>
/// Decides which check connectedness operations are needed for the given node and edge of fixed direction
/// and inserts them into the search program
/// </summary>
private SearchProgramOperation decideOnAndInsertCheckConnectednessOfNodeFixedDirection(
SearchProgramOperation insertionPoint,
SearchPlanNodeNode currentNode,
SearchPlanEdgeNode edge,
CheckCandidateForConnectednessType connectednessType)
{
Debug.Assert(connectednessType == CheckCandidateForConnectednessType.Source || connectednessType == CheckCandidateForConnectednessType.Target);
// check whether the pattern edges which must be incident to the candidate node (according to the pattern)
// are really incident to it
// only if edge is already matched by now (signaled by visited)
if (edge.Visited)
{
CheckCandidateForConnectedness checkConnectedness =
new CheckCandidateForConnectedness(
currentNode.PatternElement.Name,
currentNode.PatternElement.Name,
edge.PatternElement.Name,
connectednessType);
insertionPoint = insertionPoint.Append(checkConnectedness);
}
return insertionPoint;
}