* @param <V> the type of the cache's values, which are not permitted to be null
 * @author Charles Fry
 * @since 10.0
 */
@DoNotMock("Use CacheBuilder.newBuilder().build()")
@GwtCompatible
@ElementTypesAreNonnullByDefault
public interface Cache<K, V> {

  /**
   * Returns the value associated with {@code key} in this cache, or {@code null} if there is no

 * CacheLoader<Key, Graph> loader = new CacheLoader<Key, Graph>() {
 *   public Graph load(Key key) throws AnyException {
 *     return createExpensiveGraph(key);
 *   }
 * };
 * LoadingCache<Key, Graph> cache = CacheBuilder.newBuilder().build(loader);
 * }</pre>
 *
 * <p>Since this example doesn't support reloading or bulk loading, if you're able to use lambda
 * expressions it can be specified even more easily:
 *
 * <pre>{@code

      @Nullable DurationSpec refresh,
      @Nullable Strength keyStrength,
      @Nullable Strength valueStrength) {

    CacheBuilder<Object, Object> builder = CacheBuilder.newBuilder();
    if (concurrencyLevel != null) {
      builder.concurrencyLevel(concurrencyLevel);
    }
    if (initialCapacity != null) {
      builder.initialCapacity(initialCapacity);
    }

        () -> CacheBuilder.newBuilder().weigher(constantWeigher(42)).maximumSize(1));
    assertThrows(
        IllegalStateException.class,
        () -> CacheBuilder.newBuilder().maximumSize(1).weigher(constantWeigher(42)));
  }

  @GwtIncompatible // weakKeys
  public void testKeyStrengthSetTwice() {
    CacheBuilder<Object, Object> builder1 = CacheBuilder.newBuilder().weakKeys();

      @Nullable DurationSpec refresh,
      @Nullable Strength keyStrength,
      @Nullable Strength valueStrength) {

    CacheBuilder<Object, Object> builder = CacheBuilder.newBuilder();
    if (concurrencyLevel != null) {
      builder.concurrencyLevel(concurrencyLevel);
    }
    if (initialCapacity != null) {
      builder.initialCapacity(initialCapacity);
    }

  }

  /** Returns a CacheBuilder configured according to this instance's specification. */
  CacheBuilder<Object, Object> toCacheBuilder() {
    CacheBuilder<Object, Object> builder = CacheBuilder.newBuilder();
    if (initialCapacity != null) {
      builder.initialCapacity(initialCapacity);
    }
    if (maximumSize != null) {
      builder.maximumSize(maximumSize);
    }
    if (maximumWeight != null) {

  int capacity;

  private Segment<Object, Object> segment;

  @BeforeExperiment
  void setUp() {
    LocalCache<Object, Object> cache =
        new LocalCache<>(
            CacheBuilder.newBuilder().concurrencyLevel(1).initialCapacity(capacity), null);
    checkState(cache.segments.length == 1);
    segment = cache.segments[0];
    checkState(segment.table.length() == capacity);

   * created and objects of the same class are registered on all of them.
   */
  private static final LoadingCache<Class<?>, ImmutableList<Method>> subscriberMethodsCache =
      CacheBuilder.newBuilder()
          .weakKeys()
          .build(
              new CacheLoader<Class<?>, ImmutableList<Method>>() {
                @Override

 * @param <V> the type of the cache's values, which are not permitted to be null
 * @author Charles Fry
 * @since 10.0
 */
@DoNotMock("Use CacheBuilder.newBuilder().build()")
@GwtCompatible
@ElementTypesAreNonnullByDefault
public interface Cache<K, V> {

  /**
   * Returns the value associated with {@code key} in this cache, or {@code null} if there is no

  @Override
  protected void setUp() {
    listener = queuingRemovalListener();
  }

  public void testGet() {
    Object computed = new Object();
    LoadingCache<Object, Object> cache =
        CacheBuilder.newBuilder()
            .maximumSize(0)
            .removalListener(listener)
            .build(constantLoader(computed));

    Object key = new Object();
    assertSame(computed, cache.getUnchecked(key));