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.
/**
 * 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 null result as indication to signal onComplete instead of onSuccess. 
Type parameters:
<T> – the value type/**
 * 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 <T> the value type
 */
public final class MaybeFromFuture<T> extends Maybe<T> {

    final Future<? extends T> future;

    final long timeout;

    final TimeUnit unit;

    public MaybeFromFuture(Future<? extends T> future, long timeout, TimeUnit unit) {
        this.future = future;
        this.timeout = timeout;
        this.unit = unit;
    }

    @Override
    protected void subscribeActual(MaybeObserver<? super T> 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);
                }
            }
        }
    }
}