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.map;
  
  import net.openhft.chronicle.bytes.Bytes;
  import net.openhft.chronicle.hash.serialization.BytesReader;
  import net.openhft.chronicle.hash.serialization.BytesWriter;
  import net.openhft.chronicle.hash.serialization.impl.EnumMarshallable;
  import org.jetbrains.annotations.NotNull;
  import org.jetbrains.annotations.Nullable;
  
  import java.io.File;
  import java.io.IOException;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.UUID;
  
  import static java.util.stream.Collectors.toMap;
  
  public class Issue58 {
      File mapFile = new File("string-to-uuid.dat");
      File reverseMapFile = new File("uuid-to-string.dat");
  
      public static void main(String... args) {
          Map<String, UUID> map = new HashMap<>();
          map.put("AA", UUID.randomUUID());
          map.put("AB", UUID.randomUUID());
          map.put("BA", UUID.randomUUID());
          map.put("BB", UUID.randomUUID());
          try {
              Issue58 test = new Issue58();
              test.writeMapAndReverseMap(map);
              test.test1(map);
              test.test2(map);
          } catch (Exception e) {
              e.printStackTrace();
          }
      }
  
      private void writeMapAndReverseMap(Map<String, UUID> data) throws IOException {
          if (mapFile.exists())
              mapFile.delete();
          if (reverseMapFile.exists())
              reverseMapFile.delete();
  
          try (
                  ChronicleMap<String, UUID> map = ChronicleMap.of(String.class, UUID.class)
                          .averageKeySize(2)
                          .valueMarshaller(UuidMarshaller.INSTANCE)
                          .constantValueSizeBySample(UUID.randomUUID())
                          .entries(data.size())
                          .createPersistedTo(mapFile);
                  ChronicleMap<UUID, String> reverseMap = ChronicleMap.of(UUID.class, String.class)
                          .keyMarshaller(UuidMarshaller.INSTANCE)
                          .averageValueSize(2)
                          .constantKeySizeBySample(UUID.randomUUID())
                          .entries(data.size())
                          .createPersistedTo(reverseMapFile)
          ) {
  
              map.putAll(data);
              Map<UUID, String> reverse = data.keySet().stream()
                      .collect(toMap(k -> data.get(k), k -> k));
              reverseMap.putAll(reverse);
          }
      }
  
      public void test1(Map<String, UUID> data) throws IOException {
          try (
                  ChronicleMap<String, UUID> map = ChronicleMap.of(String.class, UUID.class)
                          .averageKeySize(2)
                          .valueMarshaller(UuidMarshaller.INSTANCE)
                          .constantValueSizeBySample(UUID.randomUUID())
                          .entries(data.size())
                          .createPersistedTo(mapFile);
                  ChronicleMap<UUID, String> reverseMap = ChronicleMap.of(UUID.class, String.class)
                          .keyMarshaller(UuidMarshaller.INSTANCE)
                          .constantKeySizeBySample(UUID.randomUUID())
                          .averageValueSize(2)
                          .entries(data.size())
                          .createPersistedTo(reverseMapFile)
          ) {
              System.out.println("first test passes:");
              UUID uuid = data.get("BB");
              System.out.println("BB" + " == " + reverseMap.get(uuid));
              System.out.println(uuid + " == " + map.get("BB"));
          }
      }
  
      public void test2(Map<String, UUID> data) throws IOException {
          try (
                  ChronicleMap<String, UUID> map = ChronicleMap.of(String.class, UUID.class)
                          .averageKeySize(2)
                          .valueMarshaller(UuidMarshaller.INSTANCE)
                          .constantValueSizeBySample(UUID.randomUUID())
                          .entries(data.size())
                          .createPersistedTo(mapFile);
                  ChronicleMap<UUID, String> reverseMap = ChronicleMap.of(UUID.class, String.class)
                          .keyMarshaller(UuidMarshaller.INSTANCE)
                          .constantKeySizeBySample(UUID.randomUUID())
                          .averageValueSize(2)
                          .entries(data.size())
                          .createPersistedTo(reverseMapFile)
          ) {
              System.out.println("second identical test also passes:");
              UUID uuid = data.get("BB");
              System.out.println("BB" + " == " + reverseMap.get(uuid));
              System.out.println(uuid + " == " + map.get("BB")); //returns null
              System.out.println("despite all data being present:");
              map.entrySet().forEach(e -> System.out.println(e.getKey() + "->" + e.getValue()));
              reverseMap.forEach((k, v) -> System.out.println(k + " -> " + v));
          }
      }
  
      static final class UuidMarshaller
              implements BytesReader<UUID>, BytesWriter<UUID>, EnumMarshallable<UuidMarshaller> {
          public static final UuidMarshaller INSTANCE = new UuidMarshaller();
  
          private UuidMarshaller() {
          }
  
          @Override
          public void write(Bytes bytes, @NotNull UUID uuid) {
              bytes.writeLong(uuid.getMostSignificantBits());
              bytes.writeLong(uuid.getLeastSignificantBits());
          }
  
          @NotNull
          @Override
          public UUID read(Bytes bytes, @Nullable UUID using) {
              return new UUID(bytes.readLong(), bytes.readLong());
          }
  
          @NotNull
          @Override
          public UuidMarshaller readResolve() {
              return INSTANCE;
          }
      }
  }
  