hu.akarnokd.rxjava2.internal.operators.PublisherFutureSource Maven / Gradle / Ivy

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/**
 * Copyright 2015 David Karnok and Netflix, Inc.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software distributed under the License is
 * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
 * the License for the specific language governing permissions and limitations under the License.
 */

package hu.akarnokd.rxjava2.internal.operators;

import java.util.concurrent.*;

import org.reactivestreams.*;

import hu.akarnokd.rxjava2.internal.subscriptions.ScalarAsyncSubscription;

public final class PublisherFutureSource implements Publisher {
    final Future future;
    final long timeout;
    final TimeUnit unit;

    public PublisherFutureSource(Future future, long timeout, TimeUnit unit) {
        this.future = future;
        this.timeout = timeout;
        this.unit = unit;
    }
    
    @Override
    public void subscribe(Subscriber s) {
        ScalarAsyncSubscription sas = new ScalarAsyncSubscription(s);
        s.onSubscribe(sas);
        if (!sas.isComplete()) {
            T v;
            try {
                v = unit != null ? future.get(timeout, unit) : future.get();
            } catch (Throwable ex) {
                if (!sas.isComplete()) {
                    s.onError(ex);
                }
                return;
            } finally {
                future.cancel(true); // TODO ?? not sure about this
            }
            if (v == null) {
                s.onError(new NullPointerException("The future returned null"));
            } else {
                sas.setValue(v);
            }
        }
    }
}