public static <I> Aggregator<I, Double> doubleMax(String attributePath) {
        return new MaxAggregator<I, Double>(attributePath);
    }
public static < I > Aggregator < I , Double > doubleMax ( String attributePath ) { return new MaxAggregator < I , Double > ( attributePath ) ; }
@param <I> type of the input object.
@return an aggregator that calculates the max of the input values extracted from the given attributePath.
Accepts null input values and null extracted values.
Accepts only Double input values (primitive and boxed).
Aggregation result type is Double.