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.single;
  
  import io.reactivex.rxjava3.core.*;
  import io.reactivex.rxjava3.disposables.Disposable;
  import io.reactivex.rxjava3.exceptions.*;
  import io.reactivex.rxjava3.functions.Function;
  
  public final class SingleOnErrorReturn<T> extends Single<T> {
      final SingleSource<? extends T> source;
  
      final Function<? super Throwable, ? extends T> valueSupplier;
  
      final T value;
  
      public SingleOnErrorReturn(SingleSource<? extends T> source,
              Function<? super Throwable, ? extends T> valueSupplier, T value) {
          this.source = source;
          this.valueSupplier = valueSupplier;
          this.value = value;
      }
  
      @Override
      protected void subscribeActual(final SingleObserver<? super T> observer) {
  
          source.subscribe(new OnErrorReturn(observer));
      }
  
      final class OnErrorReturn implements SingleObserver<T> {
  
          private final SingleObserver<? super T> observer;
  
          OnErrorReturn(SingleObserver<? super T> observer) {
              this.observer = observer;
          }
  
          @Override
          public void onError(Throwable e) {
              T v;
  
              if (valueSupplier != null) {
                  try {
                      v = valueSupplier.apply(e);
                  } catch (Throwable ex) {
                      Exceptions.throwIfFatal(ex);
                      observer.onError(new CompositeException(e, ex));
                      return;
                  }
              } else {
                  v = value;
              }
  
              if (v == null) {
                  NullPointerException npe = new NullPointerException("Value supplied was null");
                  npe.initCause(e);
                  observer.onError(npe);
                  return;
              }
  
              observer.onSuccess(v);
          }
  
          @Override
          public void onSubscribe(Disposable d) {
              observer.onSubscribe(d);
          }
  
          @Override
          public void onSuccess(T value) {
              observer.onSuccess(value);
          }
  
      }
  }
  