* in {@linkplain WeakReference weak} references.
 *
 * <p>Usage example:
 *
 * {@snippet :
 * ConcurrentMap<Request, Stopwatch> timers = new MapMaker()
 *     .concurrencyLevel(4)
 *     .weakKeys()
 *     .makeMap();
 * }
 *
 * <p>These features are all optional; {@code new MapMaker().makeMap()} returns a valid concurrent
 * map that behaves similarly to a {@link ConcurrentHashMap}.
 *

 * in {@linkplain WeakReference weak} references.
 *
 * <p>Usage example:
 *
 * {@snippet :
 * ConcurrentMap<Request, Stopwatch> timers = new MapMaker()
 *     .concurrencyLevel(4)
 *     .weakKeys()
 *     .makeMap();
 * }
 *
 * <p>These features are all optional; {@code new MapMaker().makeMap()} returns a valid concurrent
 * map that behaves similarly to a {@link ConcurrentHashMap}.
 *

 *   <li>{@code expireAfterWrite=[duration]}: sets {@link CacheBuilder#expireAfterWrite}.
 *   <li>{@code refreshAfterWrite=[duration]}: sets {@link CacheBuilder#refreshAfterWrite}.
 *   <li>{@code weakKeys}: sets {@link CacheBuilder#weakKeys}.
 *   <li>{@code softValues}: sets {@link CacheBuilder#softValues}.
 *   <li>{@code weakValues}: sets {@link CacheBuilder#weakValues}.
 *   <li>{@code recordStats}: sets {@link CacheBuilder#recordStats}.

 *   <li>{@code expireAfterWrite=[duration]}: sets {@link CacheBuilder#expireAfterWrite}.
 *   <li>{@code refreshAfterWrite=[duration]}: sets {@link CacheBuilder#refreshAfterWrite}.
 *   <li>{@code weakKeys}: sets {@link CacheBuilder#weakKeys}.
 *   <li>{@code softValues}: sets {@link CacheBuilder#softValues}.
 *   <li>{@code weakValues}: sets {@link CacheBuilder#weakValues}.
 *   <li>{@code recordStats}: sets {@link CacheBuilder#recordStats}.

            } else {
              return "0";
            }
          }
        };

    LoadingCache<Integer, String> recursiveCache =
        CacheBuilder.newBuilder().weakKeys().weakValues().build(recursiveLoader);
    cacheRef.set(recursiveCache);
    assertThat(recursiveCache.getUnchecked(3)).isEqualTo("3, 2, 1, 0");

    recursiveLoader =
        new CacheLoader<Integer, String>() {

            } else {
              return "0";
            }
          }
        };

    LoadingCache<Integer, String> recursiveCache =
        CacheBuilder.newBuilder().weakKeys().weakValues().build(recursiveLoader);
    cacheRef.set(recursiveCache);
    assertThat(recursiveCache.getUnchecked(3)).isEqualTo("3, 2, 1, 0");

    recursiveLoader =
        new CacheLoader<Integer, String>() {

        ConcurrentMap<K, V> newMap = new MapMaker().weakKeys().makeMap();
        checkState(newMap instanceof MapMakerInternalMap);
        newMap.putAll(map);
        return newMap;
      }
    },
    MapMakerWeakKeysWeakValues {
      @Override
      public <K extends Comparable<K>, V> Map<K, V> create(Map<K, V> map) {
        ConcurrentMap<K, V> newMap = new MapMaker().weakKeys().weakValues().makeMap();

        ConcurrentMap<K, V> newMap = new MapMaker().weakKeys().makeMap();
        checkState(newMap instanceof MapMakerInternalMap);
        newMap.putAll(map);
        return newMap;
      }
    },
    MapMakerWeakKeysWeakValues {
      @Override
      public <K extends Comparable<K>, V> Map<K, V> create(Map<K, V> map) {
        ConcurrentMap<K, V> newMap = new MapMaker().weakKeys().weakValues().makeMap();

  private static Iterable<MapMaker> allWeakKeyStrengthMakers() {
    return ImmutableList.of(createMapMaker().weakKeys(), createMapMaker().weakKeys().weakValues());
  }

  private static Iterable<MapMaker> allWeakValueStrengthMakers() {
    return ImmutableList.of(
        createMapMaker().weakValues(), createMapMaker().weakKeys().weakValues());
  }

  public void testNullParameters() throws Exception {

  private static Iterable<MapMaker> allWeakKeyStrengthMakers() {
    return ImmutableList.of(createMapMaker().weakKeys(), createMapMaker().weakKeys().weakValues());
  }

  private static Iterable<MapMaker> allWeakValueStrengthMakers() {
    return ImmutableList.of(
        createMapMaker().weakValues(), createMapMaker().weakKeys().weakValues());
  }

  public void testNullParameters() throws Exception {