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.observable;
  
  import io.reactivex.rxjava3.core.*;
  import io.reactivex.rxjava3.disposables.Disposable;
  import io.reactivex.rxjava3.exceptions.*;
  import io.reactivex.rxjava3.functions.*;
  import io.reactivex.rxjava3.internal.disposables.DisposableHelper;
  
  import java.util.Objects;
  
  public final class ObservableMapNotification<T, R> extends AbstractObservableWithUpstream<T, ObservableSource<? extends R>> {
  
      final Function<? super T, ? extends ObservableSource<? extends R>> onNextMapper;
      final Function<? super Throwable, ? extends ObservableSource<? extends R>> onErrorMapper;
      final Supplier<? extends ObservableSource<? extends R>> onCompleteSupplier;
  
      public ObservableMapNotification(
              ObservableSource<T> source,
              Function<? super T, ? extends ObservableSource<? extends R>> onNextMapper,
              Function<? super Throwable, ? extends ObservableSource<? extends R>> onErrorMapper,
              Supplier<? extends ObservableSource<? extends R>> onCompleteSupplier) {
          super(source);
          this.onNextMapper = onNextMapper;
          this.onErrorMapper = onErrorMapper;
          this.onCompleteSupplier = onCompleteSupplier;
      }
  
      @Override
      public void subscribeActual(Observer<? super ObservableSource<? extends R>> t) {
          source.subscribe(new MapNotificationObserver<>(t, onNextMapper, onErrorMapper, onCompleteSupplier));
      }
  
      static final class MapNotificationObserver<T, R>
      implements Observer<T>, Disposable {
          final Observer<? super ObservableSource<? extends R>> downstream;
          final Function<? super T, ? extends ObservableSource<? extends R>> onNextMapper;
          final Function<? super Throwable, ? extends ObservableSource<? extends R>> onErrorMapper;
          final Supplier<? extends ObservableSource<? extends R>> onCompleteSupplier;
  
          Disposable upstream;
  
          MapNotificationObserver(Observer<? super ObservableSource<? extends R>> actual,
                  Function<? super T, ? extends ObservableSource<? extends R>> onNextMapper,
                  Function<? super Throwable, ? extends ObservableSource<? extends R>> onErrorMapper,
                  Supplier<? extends ObservableSource<? extends R>> onCompleteSupplier) {
              this.downstream = actual;
              this.onNextMapper = onNextMapper;
              this.onErrorMapper = onErrorMapper;
              this.onCompleteSupplier = onCompleteSupplier;
          }
  
          @Override
          public void onSubscribe(Disposable d) {
              if (DisposableHelper.validate(this.upstream, d)) {
                  this.upstream = d;
                  downstream.onSubscribe(this);
              }
          }
  
          @Override
          public void dispose() {
              upstream.dispose();
          }
  
          @Override
          public boolean isDisposed() {
              return upstream.isDisposed();
          }
  
          @Override
          public void onNext(T t) {
              ObservableSource<? extends R> p;
  
              try {
                  p = Objects.requireNonNull(onNextMapper.apply(t), "The onNext ObservableSource returned is null");
              } catch (Throwable e) {
                  Exceptions.throwIfFatal(e);
                  downstream.onError(e);
                  return;
              }
  
              downstream.onNext(p);
          }
  
          @Override
          public void onError(Throwable t) {
              ObservableSource<? extends R> p;
  
              try {
                  p = Objects.requireNonNull(onErrorMapper.apply(t), "The onError ObservableSource returned is null");
              } catch (Throwable e) {
                  Exceptions.throwIfFatal(e);
                  downstream.onError(new CompositeException(t, e));
                  return;
              }
  
              downstream.onNext(p);
              downstream.onComplete();
          }
  
          @Override
          public void onComplete() {
              ObservableSource<? extends R> p;
  
              try {
                  p = Objects.requireNonNull(onCompleteSupplier.get(), "The onComplete ObservableSource returned is null");
              } catch (Throwable e) {
                  Exceptions.throwIfFatal(e);
                  downstream.onError(e);
                  return;
              }
  
              downstream.onNext(p);
              downstream.onComplete();
          }
      }
  }
  