orderByFrequency()

Implementation Notes

This implementation reads the entire stream before emitting any results making it inappropriate for infinite streams. Since this Gatherer is not order dependent it has a parallel-capable implementation. All results are wrapped in a WithCountrecord.

Signature

orderByFrequency(Frequency order)

• order - Either Ascending or Descending

Examples

Order elements by frequency, ascending

Stream
    .of("A", "A", "A", "B", "B", "B", "B", "C", "C");
    .gather(Gatherers4j.orderByFrequency(Frequency.Ascending))
    .toList();
    
// [ WithCount("C", 2), WithCount("A", 3), WithCount("B", 4) ]

Order elements by frequency, descending

Stream
    .of("A", "A", "A", "B", "B", "B", "B", "C", "C");
    .gather(Gatherers4j.orderByFrequency(Frequency.Descending))
    .toList();
    
// [ WithCount("B", 4), WithCount("A", 3), WithCount("C", 2) ]