#Java #RxJava

Reactive programming

Flux

https://tech.io/playgrounds/929/reactive-programming-with-reactor-3/Flux

  1. Return an empty Flux

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    Flux<String> emptyFlux() {
    	return Flux.empty();
    }

  2. Return a Flux that contains 2 values “foo” and “bar” without using an array or a collection

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    Flux<String> fooBarFluxFromValues() {
    		return Flux.just("foo", "bar");
    	}

  3. Create a Flux from a List that contains 2 values “foo” and “bar”

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Flux<String> fooBarFluxFromList() {
	    
		return Flux.fromIterable(Arrays.asList("foo", "bar"));
	}
  1. Reactive Streams defines the onError signal to deal with exceptions. Note that such an event is terminal: this is the last event the Flux will produce.

Last event임을 반드시 알고 넘어가자 

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Flux<String> errorFlux() {
	return Flux.error(new IllegalStateException());
}

무슨 에러 인지 읽어보기 테스트

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Flux.error(new Exception("룰루랄라"))
        .doOnError(System.out::println)
        .subscribe();

Mono

  1. Return an empty Mono

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    Mono<String> emptyMono() {
    	return Mono.empty();
    }

  2. Return a Mono that contains a “foo” value

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Mono<String> fooMono() {
	return Mono.just("foo");
}
  1. Create a Mono that emits an IllegalStateException
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Mono<String> errorMono() {
	return Mono.error(new IllegalStateException());
}

StepVerifier

  • Test에 쓸수 있어요!! nonblocking디버깅에 유용
  1. Use StepVerifier to check that the flux parameter emits “foo” and “bar” elements then completes successfully.
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void expectFooBarComplete(Flux<String> flux) {
	

		Flux<String> just = Flux.just("foo", "bar");

	StepVerifier.create(just)
			.expectNext("foo")
			.expectNext("bar")
			.verifyComplete();
}
  1. Use StepVerifier to check that the flux parameter emits “foo” and “bar” elements then a RuntimeException error.
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void expectFooBarError(Flux<String> flux) {

			StepVerifier.create(flux)
			.expectNext("foo")
			.expectNext("bar")
			.verifyError(RuntimeException.class);
}
#Java #RxJava