[RxJava] fromCallable

3. fromCallable

fromCallable은 java.util.concurrent.Callable 함수형 인터페이스에서 생성한 데이터를 통지하는 연산자로 인자로 지정한 Callable의 반환 값을 데이터로 탐지하고, 작업을 마치면 완료 통지 Flowable/Observable을 생성. 통지하는 데이터는 호출될 때마다 새로 생성.

[코드]

public class Main {
    public static void main(String[] args) {
        formCallble();
    }
    static void formCallble() {
        Flowable<Long> flowable = Flowable.fromCallable(() -> System.currentTimeMillis());
        flowable.subscribe(new PrintSubscriber<>());
    }
}

[Subscribe 코드]

import io.reactivex.subscribers.DisposableSubscriber;

public class PrintSubscriber<T> extends DisposableSubscriber<T> {

    private String label;

    public PrintSubscriber() {
    }

    public PrintSubscriber(String label) {
        this.label = label;
    }
    @Override
    public void onNext(T data) {
        String threadName = Thread.currentThread().getName();
        String resultMsg = label == null ? (threadName + " : " + data) : (threadName + " : "+ label + " : "+ data);
        System.out.println(resultMsg);
    }

    @Override
    public void onError(Throwable throwable) {
        String threadName = Thread.currentThread().getName();
        String resultMsg = label == null ? (threadName + " : Exception=" + throwable) : (threadName + " : "+ label + " : "+ throwable);
        System.out.println(resultMsg);
    }

    @Override
    public void onComplete() {
        String threadName = Thread.currentThread().getName();
        String resultMsg = label == null ? (threadName + " : Complete") : (threadName + " : "+ label + " : Complete");
        System.out.println(resultMsg);
    }
}

[결과]

main : 1564377950141
main : Complete