public static Collector < MonetaryAmount , GroupMonetarySummaryStatistics , GroupMonetarySummaryStatistics > groupBySummarizingMonetary ( ) { return Collector . of ( GroupMonetarySummaryStatistics :: new , GroupMonetarySummaryStatistics :: accept , GroupMonetarySummaryStatistics :: combine ) ; }
of MonetaryAmount group by MonetarySummary