code: /*
   * Copyright 2012-2018 Chronicle Map 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 net.openhft.chronicle.set;
  
  import net.openhft.chronicle.hash.ChronicleHash;
  import net.openhft.chronicle.hash.ChronicleHashBuilder;
  import net.openhft.chronicle.threads.NamedThreadFactory;
  import org.junit.Test;
  
  import java.io.File;
  import java.io.IOException;
  import java.util.HashSet;
  import java.util.Random;
  import java.util.Set;
  import java.util.concurrent.ExecutorService;
  import java.util.concurrent.Executors;
  
  import static com.samskivert.util.CollectionUtil.selectRandomSubset;
  
  public class Issue24ChronicleSetTest {
  
      public static <K, H extends ChronicleHash<K, ?, ?, ?>, B extends ChronicleHashBuilder<K, H, B>>
      H init(B builder, int entrySize, int averageKeySize) throws IOException {
  
          File file = File.createTempFile("stringSet", ".dat");
          file.deleteOnExit();
          try {
              H result = builder.entries(entrySize)
                      .averageKeySize(averageKeySize).createPersistedTo(file);
              return result;
          } catch (IOException ioe) {
              throw new RuntimeException(ioe);
          }
      }
  
      public synchronized static <A> ChronicleSet<A> initSet(
              Class<A> entryClass, int entrySize, int averageKeySize)
              throws IOException {
          return init(ChronicleSetBuilder.of(entryClass), entrySize, averageKeySize);
      }
  
      @Test
      public void issue24ChronicleSetTest() throws IOException {
          ChronicleSet<String> set = initSet(String.class, 1_000_000, 30);
          ExecutorService executor = Executors.newFixedThreadPool(5,
                  new NamedThreadFactory("test"));
          for (int i = 0; i < 10; i++) {
              Runnable worker = new WorkerThread(set);
              executor.execute(worker);
          }
          executor.shutdown();
          while (!executor.isTerminated()) {
  
          }
          System.out.println("Finished all threads");
  
      }
  
      public static class WorkerThread implements Runnable {
          private final ChronicleSet<String> set;
  
          public WorkerThread(ChronicleSet<String> set) {
              this.set = set;
          }
  
          @Override
          public void run() {
              System.out.println(Thread.currentThread().getName() + " Start. Command = " + set.size());
              processCommand();
              System.out.println(Thread.currentThread().getName() + " End.");
          }
  
          private void processCommand() {
              Set<String> nomenclatures = new HashSet<>();
              for (int i = 0; i < 10; i++) {
                  String nomenclature = "#############################" + i;
                  nomenclatures.add(nomenclature);
  
              }
  
              set.addAll(nomenclatures);
  
              Set<String> strings = new HashSet<>(
                      selectRandomSubset(nomenclatures, nomenclatures.size() / 2));
  
              set.addAll(strings);
  
              Set<String> toRemove = new HashSet<>();
              Random generator = new Random();
              for (int j = 0; j < 3; j++) {
                  int i = generator.nextInt(10);
                  String nomenclature = "#############################" + i;
                  toRemove.add(nomenclature);
              }
              set.removeAll(toRemove);
  
              for (String s : set) {
                  System.out.println(s);
              }
  
              strings = new HashSet<>(selectRandomSubset(
                      nomenclatures, nomenclatures.size() / 2));
  
              set.addAll(strings);
  
              for (String s : set) {
                  System.out.println(s);
              }
          }
      }
  }
  