private static void HandlePrevious(IList <ExprPreviousNode> previousRequests, Object previousNodeGetter, IDictionary <ExprPreviousNode, ExprPreviousEvalStrategy> strategies)
{
if (previousRequests.IsEmpty())
{
return;
}
RandomAccessByIndexGetter randomAccessGetter = null;
RelativeAccessByEventNIndexMap relativeAccessGetter = null;
if (previousNodeGetter is RandomAccessByIndexGetter)
{
randomAccessGetter = (RandomAccessByIndexGetter)previousNodeGetter;
}
else if (previousNodeGetter is RelativeAccessByEventNIndexMap)
{
relativeAccessGetter = (RelativeAccessByEventNIndexMap)previousNodeGetter;
}
else
{
throw new EPException("Unexpected 'previous' handler: " + previousNodeGetter);
}
foreach (ExprPreviousNode previousNode in previousRequests)
{
int streamNumber = previousNode.StreamNumber;
ExprPreviousNodePreviousType previousType = previousNode.PreviousType;
ExprPreviousEvalStrategy evaluator;
if (previousType == ExprPreviousNodePreviousType.PREVWINDOW)
{
evaluator = new ExprPreviousEvalStrategyWindow(streamNumber, previousNode.ChildNodes[1].ExprEvaluator, previousNode.ReturnType.GetElementType(),
randomAccessGetter, relativeAccessGetter);
}
else if (previousType == ExprPreviousNodePreviousType.PREVCOUNT)
{
evaluator = new ExprPreviousEvalStrategyCount(streamNumber, randomAccessGetter, relativeAccessGetter);
}
else
{
evaluator = new ExprPreviousEvalStrategyPrev(streamNumber, previousNode.ChildNodes[0].ExprEvaluator, previousNode.ChildNodes[1].ExprEvaluator,
randomAccessGetter, relativeAccessGetter, previousNode.IsConstantIndex, previousNode.ConstantIndexNumber, previousType == ExprPreviousNodePreviousType.PREVTAIL);
}
strategies.Put(previousNode, evaluator);
}
}
public ExprPreviousNode(ExprPreviousNodePreviousType previousType)
{
_previousType = previousType;
}
