window()

Create windows over the elements of the input stream that are windowSize in length, sliding over stepping number of elements and optionally including partial windows at the end of ths stream.

Implementation Notes

The lists returned from this Gatherer are unmodifiable. The stepping may be larger than the windowSize, in which case elements are skipped.

Fun fact: calling window(2, 1, true) or window(2, 1, false) is the same as zipWithNext()!

Signature

window(int windowSize, int stepping, boolean includePartials)

windowSize - How many elements to include in each List, must be positive.
stepping - How many elements to slide over each iteration, must be positive.
includePartials - Emit any partially constructed windows at the end of the stream.

Examples

Window size 2, stepping 2, not including partials

The function groups consecutive elements of equal length

Stream
    .of("A", "B", "C", "D", "E", "F", "G");
    .gather(Gatherers4j.window(2, 2, false))
    .toList();

// [ ["A", "B"], ["C", "D"], ["E", "F"] ]

Window size 2, stepping 3, including partials

Stream
    .of("A", "B", "C", "D", "E", "F", "G");
    .gather(Gatherers4j.window(2, 3, true))
    .toList();

// [ ["A", "B"], ["D", "E"], ["G"] ]