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.flowable;
  
  import org.reactivestreams.Subscriber;
  
  import io.reactivex.rxjava3.core.Flowable;
  import io.reactivex.rxjava3.exceptions.*;
  import io.reactivex.rxjava3.functions.Function;
  import io.reactivex.rxjava3.internal.subscribers.SinglePostCompleteSubscriber;
  
  import java.util.Objects;
  
  public final class FlowableOnErrorReturn<T> extends AbstractFlowableWithUpstream<T, T> {
      final Function<? super Throwable, ? extends T> valueSupplier;
      public FlowableOnErrorReturn(Flowable<T> source, Function<? super Throwable, ? extends T> valueSupplier) {
          super(source);
          this.valueSupplier = valueSupplier;
      }
  
      @Override
      protected void subscribeActual(Subscriber<? super T> s) {
          source.subscribe(new OnErrorReturnSubscriber<>(s, valueSupplier));
      }
  
      static final class OnErrorReturnSubscriber<T>
      extends SinglePostCompleteSubscriber<T, T> {
  
          private static final long serialVersionUID = -3740826063558713822L;
          final Function<? super Throwable, ? extends T> valueSupplier;
  
          OnErrorReturnSubscriber(Subscriber<? super T> actual, Function<? super Throwable, ? extends T> valueSupplier) {
              super(actual);
              this.valueSupplier = valueSupplier;
          }
  
          @Override
          public void onNext(T t) {
              produced++;
              downstream.onNext(t);
          }
  
          @Override
          public void onError(Throwable t) {
              T v;
              try {
                  v = Objects.requireNonNull(valueSupplier.apply(t), "The valueSupplier returned a null value");
              } catch (Throwable ex) {
                  Exceptions.throwIfFatal(ex);
                  downstream.onError(new CompositeException(t, ex));
                  return;
              }
              complete(v);
          }
  
          @Override
          public void onComplete() {
              downstream.onComplete();
          }
      }
  }
  