com.gs.api.accelrx.context.rxjava3.ContextPropagatorOnObservableSubscribeAction Maven / Gradle / Ivy

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package com.gs.api.accelrx.context.rxjava3;

import io.reactivex.rxjava3.annotations.NonNull;
import io.reactivex.rxjava3.core.Observable;
import io.reactivex.rxjava3.core.Observer;
import io.reactivex.rxjava3.disposables.Disposable;
import io.reactivex.rxjava3.functions.BiFunction;

import java.util.concurrent.Executor;

@SuppressWarnings("rawtypes")
public class ContextPropagatorOnObservableSubscribeAction implements BiFunction {

    private final ThreadContext threadContext;

    public ContextPropagatorOnObservableSubscribeAction(ThreadContext threadContext) {
        this.threadContext = threadContext;
    }

    @Override
    @SuppressWarnings({"rawtypes", "unchecked"})
    public Observer apply(Observable maybe, Observer observer) throws Throwable {
        return new ContextCapturerObservable<>(observer, threadContext.currentContextExecutor());
    }

    private static final class ContextCapturerObservable implements Observer {

        private final Observer downstream;
        private final Executor contextExecutor;

        public ContextCapturerObservable(Observer observer, Executor contextExecutor) {
            this.downstream = observer;
            this.contextExecutor = contextExecutor;
        }

        @Override
        public void onSubscribe(@NonNull Disposable d) {
            contextExecutor.execute(() -> downstream.onSubscribe(d));
        }

        @Override
        public void onNext(@NonNull T t) {
            contextExecutor.execute(() -> downstream.onNext(t));
        }

        @Override
        public void onError(@NonNull Throwable e) {
            contextExecutor.execute(() -> downstream.onError(e));
        }

        @Override
        public void onComplete() {
            contextExecutor.execute(downstream::onComplete);
        }
    }
}