group()

Turn a Stream<INPUT> into a Stream<List<INPUT>> where adjacent equal elements are in the same List and equality is measured by Object::equals().

Implementation Notes

This function groups adjacent equal elements as measured by Object::equals() into lists. The lists returned from this Gatherer are unmodifiable. For the purposes of this gatherer, nulls are equal to each other but not equal to anything else.

For a version of group() that measures equality with a user-provided function, see the groupBy()Gatherer.

Signature

group()

Examples

Group adjacent equal elements

Stream
    .of("A", "A", "BB", "BB", "CCC", "A")
    .gather(Gatherers4j.group())
    .toList();

// [ ["A", "A"], ["BB", "BB"], ["CCC"], ["A"] ]