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.observers;
  
  import java.util.concurrent.atomic.AtomicReference;
  
  import io.reactivex.rxjava3.core.SingleObserver;
  import io.reactivex.rxjava3.disposables.Disposable;
  import io.reactivex.rxjava3.internal.disposables.DisposableHelper;
  
  /**
   * A SingleObserver implementation used for subscribing to the actual SingleSource
   * and replace the current Disposable in a parent AtomicReference.
   *
   * @param <T> the value type
   */
  public final class ResumeSingleObserver<T> implements SingleObserver<T> {
  
      final AtomicReference<Disposable> parent;
  
      final SingleObserver<? super T> downstream;
  
      public ResumeSingleObserver(AtomicReference<Disposable> parent, SingleObserver<? super T> downstream) {
          this.parent = parent;
          this.downstream = downstream;
      }
  
      @Override
      public void onSubscribe(Disposable d) {
          DisposableHelper.replace(parent, d);
      }
  
      @Override
      public void onSuccess(T value) {
          downstream.onSuccess(value);
      }
  
      @Override
      public void onError(Throwable e) {
          downstream.onError(e);
      }
  }
  