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.xmapz;
  
  import java.util.Arrays;
  import java.util.concurrent.TimeUnit;
  
  import org.openjdk.jmh.annotations.*;
  import org.openjdk.jmh.infra.Blackhole;
  
  import io.reactivex.rxjava3.core.*;
  import io.reactivex.rxjava3.functions.Function;
  
  @BenchmarkMode(Mode.Throughput)
  @Warmup(iterations = 5)
  @Measurement(iterations = 5, time = 1, timeUnit = TimeUnit.SECONDS)
  @OutputTimeUnit(TimeUnit.SECONDS)
  @Fork(value = 1)
  @State(Scope.Thread)
  public class ObservableConcatMapMaybeEmptyPerf {
      @Param({ "1", "10", "100", "1000", "10000", "100000", "1000000" })
      public int count;
  
      Observable<Integer> concatMapToObservableEmpty;
  
      Observable<Integer> observableDedicated;
  
      Observable<Integer> observablePlain;
  
      @Setup
      public void setup() {
          Integer[] sourceArray = new Integer[count];
          Arrays.fill(sourceArray, 777);
  
          Observable<Integer> source = Observable.fromArray(sourceArray);
  
          observablePlain = source.concatMap(new Function<Integer, Observable<? extends Integer>>() {
              @Override
              public Observable<? extends Integer> apply(Integer v) {
                  return Observable.empty();
              }
          });
  
          concatMapToObservableEmpty = source.concatMap(new Function<Integer, Observable<? extends Integer>>() {
              @Override
              public Observable<? extends Integer> apply(Integer v) {
                  return Maybe.<Integer>empty().toObservable();
              }
          });
  
          observableDedicated = source.concatMapMaybe(new Function<Integer, Maybe<? extends Integer>>() {
              @Override
              public Maybe<? extends Integer> apply(Integer v) {
                  return Maybe.empty();
              }
          });
      }
  
      @Benchmark
      public Object observablePlain(Blackhole bh) {
          return observablePlain.subscribeWith(new PerfConsumer(bh));
      }
  
      @Benchmark
      public Object observableConvert(Blackhole bh) {
          return concatMapToObservableEmpty.subscribeWith(new PerfConsumer(bh));
      }
  
      @Benchmark
      public Object observableDedicated(Blackhole bh) {
          return observableDedicated.subscribeWith(new PerfConsumer(bh));
      }
  }
  