groupedWeighted

Accumulate incoming events until the combined weight of elements is greater than or equal to the minimum weight and then pass the collection of elements downstream.

Simple operators

Signature¶

Source.groupedWeightedSource.groupedWeighted Flow.groupedWeightedFlow.groupedWeighted

Description¶

Chunk up this stream into groups of elements that have a cumulative weight greater than or equal to the minWeight, with the last group possibly smaller than requested minWeight due to end-of-stream.

See also:

• grouped for a variant that groups based on number of elements
• groupedWithin for a variant that groups based on number of elements and a time window
• groupedWeightedWithin for a variant that groups based on element weight and a time window

Examples¶

The below example demonstrates how groupedWeighted groups the accumulated elements into Seq List and maps with other operation.

Scala

Java

copysourceval collections = immutable.Iterable(Seq(1, 2), Seq(3, 4), Seq(5, 6))
Source[Seq[Int]](collections).groupedWeighted(4)(_.length).runForeach(println)
// Vector(Seq(1, 2), Seq(3, 4))
// Vector(Seq(5, 6))

Source[Seq[Int]](collections).groupedWeighted(3)(_.length).runForeach(println)
// Vector(Seq(1, 2), Seq(3, 4))
// Vector(Seq(5, 6))

copysourceSource.from(Arrays.asList(Arrays.asList(1, 2), Arrays.asList(3, 4), Arrays.asList(5, 6)))
    .groupedWeighted(4, x -> (long) x.size())
    .runForeach(System.out::println, system);
// [[1, 2], [3, 4]]
// [[5, 6]]

Source.from(Arrays.asList(Arrays.asList(1, 2), Arrays.asList(3, 4), Arrays.asList(5, 6)))
    .groupedWeighted(3, x -> (long) x.size())
    .runForeach(System.out::println, system);
// [[1, 2], [3, 4]]
// [[5, 6]]

Reactive Streams semantics¶