code: /*
   * 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.rxjava3.internal.operators.maybe;
  
  import java.util.concurrent.TimeUnit;
  import java.util.concurrent.atomic.AtomicReference;
  
  import io.reactivex.rxjava3.core.*;
  import io.reactivex.rxjava3.disposables.Disposable;
  import io.reactivex.rxjava3.internal.disposables.DisposableHelper;
  
  /**
   * Signals a {@code 0L} after the specified delay.
   */
  public final class MaybeTimer extends Maybe<Long> {
  
      final long delay;
  
      final TimeUnit unit;
  
      final Scheduler scheduler;
  
      public MaybeTimer(long delay, TimeUnit unit, Scheduler scheduler) {
          this.delay = delay;
          this.unit = unit;
          this.scheduler = scheduler;
      }
  
      @Override
      protected void subscribeActual(final MaybeObserver<? super Long> observer) {
          TimerDisposable parent = new TimerDisposable(observer);
          observer.onSubscribe(parent);
          parent.setFuture(scheduler.scheduleDirect(parent, delay, unit));
      }
  
      static final class TimerDisposable extends AtomicReference<Disposable> implements Disposable, Runnable {
  
          private static final long serialVersionUID = 2875964065294031672L;
          final MaybeObserver<? super Long> downstream;
  
          TimerDisposable(final MaybeObserver<? super Long> downstream) {
              this.downstream = downstream;
          }
  
          @Override
          public void run() {
              downstream.onSuccess(0L);
          }
  
          @Override
          public void dispose() {
              DisposableHelper.dispose(this);
          }
  
          @Override
          public boolean isDisposed() {
              return DisposableHelper.isDisposed(get());
          }
  
          void setFuture(Disposable d) {
              DisposableHelper.replace(this, d);
          }
      }
  }
  