Devoxx - filter, partition and offset
brian.goetz at oracle.com
Wed Apr 3 05:22:44 PDT 2013
> The partitioningBy method also looked very confusing. My take on
> parttition as a concept was to split a list into two lists. Reading
> the documentation and the method signature didn't tell me what the
> method does at all. I certainly didn't grok the boolean.
In a functional language where tuples and lists are built in, the
natural return type for partition is a tuple of lists. But we don't get
it that easy.
We experimented with a number of forms here; a two-element array (arrays
and generics don't play nicely), a special Partition object, etc. In
the end a Map<Boolean, List<T>> seemed most natural, and also behaved
mostly like the other composible Collector combinator, groupingBy.
> With an API contaiing limit(), my database work expected me to see a
> matching offset(). I understand that there are issues with parallel,
> but it looked like an omission.
substream(n) and substream(n, m).
More information about the lambda-dev