Reactive programming with Java 8 and simple-react : firstOf, allOf & anyOf

firstOf!

simple-react can take an array of FutureStreams and ‘run a race’ between them. It will return a Stream of values from the first one to start emitting values, the other Streams will be closed.

Example

LazyFutureStream stream1 = 
                   LazyFutureStream.sequentialBuilder()
                                .react(()->loadFromDb())
                                .map(this::convertToStandardFormat)
LazyFutureStream stream2 = 
                   LazyFutureStream.sequentialBuilder()
                                .react(()->loadFromService1())
                                .map(this::convertToStandardFormat)
LazyFutureStream stream3 = 
                   LazyFutureStream.sequentialBuilder()
                                .react(()->loadFromService2())
                                .map(this::convertToStandardFormat)
LazyFutureStream.firstOf(stream1,stream2,stream3)
                .map(this::save)
                .runOnCurrent()

anyOf!

anyOf continues the Stream with the first value in a Stream to be emitted.

LazyFutureStream.parallelBuilder()
                .react(() -> loadFromDb(),
                       () -> loadFromService1(),
                       () -> loadFromService2())
                .anyOf(Function.<String>identity())
                .map(this::convertToStandardFormat)
                .peek(System.out::println)
                .map(this::saveData)
                .run(()-> new ArrayList<>());

NB filtering short-circuits the internal chain of CompletableFutures, and may result in an empty completed value.

allOf!

allOf asynchronously collects all the data in a Stream into a Collection. It’s roughly equivalent to collect or block, but is asynchronous and the Stream can continue, albeit with a single value.

The Tutorial : Reactive programming with Java 8