问为什么不调用可完成的任务？
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Stack Overflow用户

提问于 2018-06-26 06:39:35

回答 1查看 522关注 0票数 1

所以刚到RX的家伙们我有个问题。

在我学习野兽的探险中，也就是RXJava，这是我的课程。

public class PollingLoop {

public static <T> Observable<T> buildObservable(
    final int interval,
    final TimeUnit timeUnit,
    final int maxJitter,
    final Scheduler scheduler,
    final Supplier<Observable<T>> scheduledTask) {

    if (maxJitter <= 0) throw new IllegalArgumentException("Jitter must be greater than 0");

    final Random randomJitter = new Random();
    return Observable.timer(interval, timeUnit, scheduler)
        .map(x -> {
            System.out.println("Flat map jitter");
            return randomJitter.nextInt(maxJitter);
        })
        .flatMap(jitter -> {
            System.out.println("Flat map timer");
            return Observable.timer(jitter, timeUnit, scheduler);
        })
        .flatMap(ignored -> {
            System.out.println("Flat map task");
            return scheduledTask.get();
        })
        .retry()
        .repeat();
}

public static <T> Completable buildCompletable(
    final int interval,
    final TimeUnit timeUnit,
    final int maxJitter,
    final Scheduler scheduler,
    final Supplier<Completable> scheduledTask) {

    if (maxJitter <= 0) throw new IllegalArgumentException("Jitter must be greater than 0");

    final Random randomJitter = new Random();
    return Observable.timer(interval, timeUnit, scheduler)
        .map(x -> {
            System.out.println("Flat map jitter");
            return randomJitter.nextInt(maxJitter);
        })
        .flatMapCompletable(jitter -> {
            System.out.println("Flat map timer");
            return Completable.timer(jitter, timeUnit, scheduler);
        })
        .flatMapCompletable(ignored -> {
            System.out.println("Flat map task that is not called");
            return scheduledTask.get();
        })
        .retry()
        .repeat()
        .toCompletable();
}
}

从测试中，当我测试可观察到的执行延迟时，我得到了输出。

Flat map jitter
Flat map timer
Flat map task //(observable is being called)

但是当我测试可完全执行的延迟时，我得到了输出。

Flat map jitter
Flat map timer

//(未调用可完成的任务)

我做错什么了？为什么不能从buildCompletable内部调用可完成的任务？

这是测试(用斯波克写的)

def 'should delay execution of observable'() {
    given:
    def subscriber = new TestSubscriber<>()
    def scheduler = new TestScheduler()
    def supplier = Mock Supplier

    supplier.get() >> Observable.just(true)

    when:
    PollingLoop.buildObservable(100, TimeUnit.MILLISECONDS, 1, scheduler, supplier).subscribe(subscriber)
    scheduler.advanceTimeBy(101, TimeUnit.MILLISECONDS)

    then:
    subscriber.assertValueCount(1)
    subscriber.assertValue(true)
}

    def 'should delay execution of completable'(){
    given:
    def subscriber = new TestSubscriber<>()
    def scheduler = new TestScheduler()
    def supplier = Mock Supplier
    supplier.get() >> Completable.complete()

    when:
    PollingLoop.buildCompletable(100, TimeUnit.MILLISECONDS, 1, scheduler, supplier).subscribe(subscriber)

    scheduler.advanceTimeBy(1001, TimeUnit.MILLISECONDS)
enter code here
    then:
    1 * supplier.get()
}