Buffering
The buffer() operator will gather emissions within a certain scope and emit each batch as a list or another collection type. The scope can be defined by a fixed buffer sizing or a timing window that cuts off at intervals or even slices by the emissions of another Observable.
Fixed-size buffering
The simplest overload for buffer() accepts a count argument that batches emissions in that fixed size. If we wanted to batch up emissions into lists of eight elements, we can do that as follows:
import io.reactivex.Observable;
public class Launcher {
public static void main(String[] args) {
Observable.range(1,50)
.buffer(8)
.subscribe(System.out::println);
}
}The output is as follows:
[1, 2, 3, 4, 5, 6, 7, 8] [9, 10, 11, 12, 13, 14, 15, 16] [17, 18, 19, 20, 21, 22, 23, 24] [25, 26, 27, 28, 29, 30, 31, 32] [33, 34, 35, 36, 37, 38, 39, 40] [41, 42, 43, 44, 45, 46, 47, 48] [49, 50]
Of course, if the number of emissions does not cleanly divide, the remaining...