public interface IBoundaryItemUndefinedData| GetAccumulatedValue | Get boundary value accumulated over the specified period, returning also the accumulationTime which keeps track of the time within the period where values are not undefined. If all values within the specific period is undefined, the accumulationTime is zero and the method returns zero. It is the callers responsibility to check if the item is applicable at the given datetime before calling GetAccumulatedValue. If the item is only applicable over a part of the interval, it must return the accumulated value for that part of the interval. |