io.servicetalk.concurrent.api

Interface BufferStrategy<T,BC extends BufferStrategy.Accumulator<T,B>,B>

Type Parameters:

T - items emitted from the Publisher which are to be buffered using this BufferStrategy.

BC - An intermediate mutable object that holds the items into a buffer before it is emitted.

B - The buffer of items.

public interface BufferStrategy<T,BC extends BufferStrategy.Accumulator<T,B>,B>

A strategy for buffering items emitted from a Publisher.

A buffer strategy represents asynchronous buffer boundaries over which items from a Publisher are buffered. Each item emitted from the boundary Publisher represents the end of the last boundary and start of the next boundary. The first item emitted from this Publisher is treated as the start of the first boundary and Publisher.buffer(BufferStrategy) may decide to defer requesting items from the Publisher on which that operator is applied.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static interface	BufferStrategy.Accumulator<T,B> An intermediate mutable object that holds items till it is finished.

Method Summary

Modifier and Type	Method and Description
Publisher<BC>	boundaries() Returns a Publisher representing asynchronous buffer boundaries.
int	bufferSizeHint() A rough estimate of the number of items in a buffer.

Method Detail

boundaries

Publisher<BC> boundaries()

Returns a Publisher representing asynchronous buffer boundaries.

Notes:

1. This Publisher is expected to be an infinite Publisher. Hence, it should never terminate any PublisherSource.Subscriber subscribed to it. Instead PublisherSource.Subscribers will always cancel their PublisherSource.Subscription. If this expectation is violated, buffered items may be discarded.
2. If this Publisher returns more boundaries faster than accumulation or emission of the previous boundary can be processed, these new boundaries may be discarded without invocation of either BufferStrategy.Accumulator.accumulate(Object) or BufferStrategy.Accumulator.finish() methods. Avoid initializing expensive state before any of the BufferStrategy.Accumulator methods are invoked.

Returns:

A Publisher representing asynchronous buffer boundaries.

bufferSizeHint

int bufferSizeHint()

A rough estimate of the number of items in a buffer.

Note: if boundaries() are generated based on the number of accumulated items, this hint size MUST always be equal or less than the number of items that generates a boundary. Otherwise, there is a risk of emitting more buffers than requested.

Returns:

A rough estimate of the number of items in a buffer.