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.CountDownLatch;
  
  import io.reactivex.rxjava3.annotations.NonNull;
  import io.reactivex.rxjava3.core.*;
  import io.reactivex.rxjava3.disposables.Disposable;
  import io.reactivex.rxjava3.internal.disposables.*;
  import io.reactivex.rxjava3.internal.util.BlockingHelper;
  
  /**
   * Blocks until the upstream terminates and dispatches the outcome to
   * the actual observer.
   *
   * @param <T> the element type of the source
   * @since 3.0.0
   */
  public final class BlockingDisposableMultiObserver<T>
  extends CountDownLatch
  implements MaybeObserver<T>, SingleObserver<T>, CompletableObserver, Disposable {
  
      T value;
      Throwable error;
  
      final SequentialDisposable upstream;
  
      public BlockingDisposableMultiObserver() {
          super(1);
          upstream = new SequentialDisposable();
      }
  
      @Override
      public void dispose() {
          upstream.dispose();
          countDown();
      }
  
      @Override
      public boolean isDisposed() {
          return upstream.isDisposed();
      }
  
      @Override
      public void onSubscribe(@NonNull Disposable d) {
          DisposableHelper.setOnce(upstream, d);
      }
  
      @Override
      public void onSuccess(@NonNull T t) {
          this.value = t;
          upstream.lazySet(Disposable.disposed());
          countDown();
      }
  
      @Override
      public void onError(@NonNull Throwable e) {
          this.error = e;
          upstream.lazySet(Disposable.disposed());
          countDown();
      }
  
      @Override
      public void onComplete() {
          upstream.lazySet(Disposable.disposed());
          countDown();
      }
  
      public void blockingConsume(CompletableObserver observer) {
          if (getCount() != 0) {
              try {
                  BlockingHelper.verifyNonBlocking();
                  await();
              } catch (InterruptedException ex) {
                  dispose();
                  observer.onError(ex);
                  return;
              }
          }
          if (isDisposed()) {
              return;
          }
  
          Throwable ex = error;
          if (ex != null) {
              observer.onError(ex);
          } else {
              observer.onComplete();
          }
      }
  
      public void blockingConsume(SingleObserver<? super T> observer) {
          if (getCount() != 0) {
              try {
                  BlockingHelper.verifyNonBlocking();
                  await();
              } catch (InterruptedException ex) {
                  dispose();
                  observer.onError(ex);
                  return;
              }
          }
          if (isDisposed()) {
              return;
          }
  
          Throwable ex = error;
          if (ex != null) {
              observer.onError(ex);
          } else {
              observer.onSuccess(value);
          }
      }
  
      public void blockingConsume(MaybeObserver<? super T> observer) {
          if (getCount() != 0) {
              try {
                  BlockingHelper.verifyNonBlocking();
                  await();
              } catch (InterruptedException ex) {
                  dispose();
                  observer.onError(ex);
                  return;
              }
          }
          if (isDisposed()) {
              return;
          }
  
          Throwable ex = error;
          if (ex != null) {
              observer.onError(ex);
          } else {
              T v = value;
              if (v == null) {
                  observer.onComplete();
              } else {
                  observer.onSuccess(v);
              }
          }
      }
  }
  