How to transform a Java stream into a sliding window?

Question

What is the recommended way to transform a stream into a sliding window?

For instance, in Ruby you could use each_cons:

irb(main):020:0> [1,2,3,4]         


        

Answer 1

if you want to bring the whole power of Scala's persistent collections to Java, you may use the library Javaslang.

// this imports List, Stream, Iterator, ...
import javaslang.collection.*;

Iterator.range(1, 5).sliding(3)
        .forEach(System.out::println);
// --->
// List(1, 2, 3)
// List(2, 3, 4)

Iterator.range(1, 5).sliding(2, 3)
        .forEach(System.out::println);
// --->
// List(1, 2)
// List(4)

Iterator.ofAll(javaStream).sliding(3);

You may not only use Iterator, this also works for almost any other Javaslang collection: Array, Vector, List, Stream, Queue, HashSet, LinkedHashSet, TreeSet, ...

(Overview Javaslang 2.1.0-alpha)

Disclaimer: I'm the creator of Javaslang