i want to group the item element according to date such that , if item object's date is greater than present date then , it will fall into futuredate group and if date is less than present date then it will fall into pastdate  

 and then i want to reduce on these group so that i can get aggregate qty,price of these group, further aggregate value returned from pastdate group shold sit in oldPrice and oldQty of object

```
 public class Item {        
            private String name;
            private int qty;
            private int oldQty;
            private BigDecimal price;
            private BigDecimal oldPrice;
            Private Date date;

            //constructors, getter/setters
        }

Map<String, List<Item>> groupByP =
            items.stream().collect(Collectors.groupingBy((row)->{
//logic to seperate items into two group based on date
}));

```

How to proceed after this