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Reactive Extensions for Java

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/**
 * Copyright (c) 2016-present, RxJava Contributors.
 *
 * 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 io.reactivex.internal.operators.maybe;

import java.util.concurrent.*;

import io.reactivex.*;
import io.reactivex.disposables.*;
import io.reactivex.exceptions.Exceptions;

/**
 * Waits until the source Future completes or the wait times out; treats a {@code null}
 * result as indication to signal {@code onComplete} instead of {@code onSuccess}.
 *
 * @param  the value type
 */
public final class MaybeFromFuture extends Maybe {

    final Future future;

    final long timeout;

    final TimeUnit unit;

    public MaybeFromFuture(Future future, long timeout, TimeUnit unit) {
        this.future = future;
        this.timeout = timeout;
        this.unit = unit;
    }

    @Override
    protected void subscribeActual(MaybeObserver observer) {
        Disposable d = Disposables.empty();
        observer.onSubscribe(d);
        if (!d.isDisposed()) {
            T v;
            try {
                if (timeout <= 0L) {
                    v = future.get();
                } else {
                    v = future.get(timeout, unit);
                }
            } catch (Throwable ex) {
                if (ex instanceof ExecutionException) {
                    ex = ex.getCause();
                }
                Exceptions.throwIfFatal(ex);
                if (!d.isDisposed()) {
                    observer.onError(ex);
                }
                return;
            }
            if (!d.isDisposed()) {
                if (v == null) {
                    observer.onComplete();
                } else {
                    observer.onSuccess(v);
                }
            }
        }
    }
}