the extractor that provides a value in the form of any numeric object or the name of the method that could be invoked via Java reflection and that returns numeric values to aggregate; this parameter can also be a dot-delimited sequence of method names which would result in an aggregator based on the ChainedExtractor that is based on an array of corresponding UniversalExtractor objects. May not be null
Server-side EntryAggregator implementation type identifier.
The extractor.ValueExtractor to apply when aggregating results.
Returns a CompositeAggregator comprised of this and the provided aggregator.
the next aggregator
a CompositeAggregator comprised of this and the provided aggregator
Calculates an sum for values of any numeric type extracted from a set of entries in a Map in a form of a numeric value.
If the set of entries is empty, a 'null' result is returned.