@ SuppressWarnings ( "unchecked" ) public < A extends SimpleAggregator , N extends Number > GroupByAggregator < A , N > createGroupBy ( String name , Class < ? extends Aggregator > aKlass ) { Utils . checkState ( ! started , "Already started" ) ; GroupByAggregator < A , N > aggregator = new GroupByAggregator ( name , aKlass , this ) ; dataProvider . addAggregator ( aggregator ) ; aggregator . setDataProvider ( dataProvider ) ; return aggregator ; }
Creates a group - by Agregator .