private Set<DurationSpec> refreshes = Sets.newHashSet((DurationSpec) null);
  private Set<Strength> keyStrengths = Sets.newHashSet((Strength) null);
  private Set<Strength> valueStrengths = Sets.newHashSet((Strength) null);

  @CanIgnoreReturnValue
  CacheBuilderFactory withConcurrencyLevels(Set<Integer> concurrencyLevels) {

      MapMaker builder) {
    if (builder.getKeyStrength() == Strength.STRONG
        && builder.getValueStrength() == Strength.STRONG) {
      return new MapMakerInternalMap<>(builder, StrongKeyStrongValueEntry.Helper.instance());
    }
    if (builder.getKeyStrength() == Strength.STRONG
        && builder.getValueStrength() == Strength.WEAK) {

      spec.keyStrength = strength;
    }
  }

  /** Parse weakValues and softValues */
  private static final class ValueStrengthParser implements ValueParser {
    private final Strength strength;

    ValueStrengthParser(Strength strength) {
      this.strength = strength;
    }

    @Override

      spec.keyStrength = strength;
    }
  }

  /** Parse weakValues and softValues */
  private static final class ValueStrengthParser implements ValueParser {
    private final Strength strength;

    ValueStrengthParser(Strength strength) {
      this.strength = strength;
    }

    @Override

      MapMaker builder) {
    if (builder.getKeyStrength() == Strength.STRONG
        && builder.getValueStrength() == Strength.STRONG) {
      return new MapMakerInternalMap<>(builder, StrongKeyStrongValueEntry.Helper.instance());
    }
    if (builder.getKeyStrength() == Strength.STRONG
        && builder.getValueStrength() == Strength.WEAK) {

        }
      };

  private CacheBuilderFactory factoryWithAllKeyStrengths() {
    return new CacheBuilderFactory()
        .withKeyStrengths(ImmutableSet.of(STRONG, Strength.WEAK))
        .withValueStrengths(ImmutableSet.of(STRONG, Strength.WEAK, Strength.SOFT));
  }

  private Iterable<LoadingCache<Key, String>> caches() {
    CacheBuilderFactory factory = factoryWithAllKeyStrengths();
    return Iterables.transform(

        }
      };

  private CacheBuilderFactory factoryWithAllKeyStrengths() {
    return new CacheBuilderFactory()
        .withKeyStrengths(ImmutableSet.of(STRONG, Strength.WEAK))
        .withValueStrengths(ImmutableSet.of(STRONG, Strength.WEAK, Strength.SOFT));
  }

  private Iterable<LoadingCache<Key, String>> caches() {
    CacheBuilderFactory factory = factoryWithAllKeyStrengths();
    return Iterables.transform(

    checkStrength(map, Strength.WEAK, Strength.STRONG);
    assertThat(map.entryHelper)
        .isInstanceOf(MapMakerInternalMap.WeakKeyStrongValueEntry.Helper.class);
  }

  public void testSetWeakValues() {
    MapMakerInternalMap<Object, Object, ?, ?> map = makeMap(createMapMaker().weakValues());
    checkStrength(map, Strength.STRONG, Strength.WEAK);
    assertThat(map.entryHelper)

    checkStrength(map, Strength.WEAK, Strength.STRONG);
    assertThat(map.entryHelper)
        .isInstanceOf(MapMakerInternalMap.WeakKeyStrongValueEntry.Helper.class);
  }

  public void testSetWeakValues() {
    MapMakerInternalMap<Object, Object, ?, ?> map = makeMap(createMapMaker().weakValues());
    checkStrength(map, Strength.STRONG, Strength.WEAK);
    assertThat(map.entryHelper)

  boolean usesAccessEntries() {
    return usesAccessQueue() || recordsAccess();
  }

  boolean usesKeyReferences() {
    return keyStrength != Strength.STRONG;
  }

  boolean usesValueReferences() {
    return valueStrength != Strength.STRONG;
  }

  enum Strength {
    /*
     * TODO(kevinb): If we strongly reference the value and aren't loading, we needn't wrap the
     * value. This could save ~8 bytes per entry.