* @param <V> the type of the cache's values, which are not permitted to be null
 * @author Charles Fry
 * @since 11.0
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public interface LoadingCache<K, V> extends Cache<K, V>, Function<K, V> {

  /**
   * Returns the value associated with {@code key} in this cache, first loading that value if

public class AbstractLoadingCacheTest extends TestCase {

  public void testGetUnchecked_checked() {
    final Exception cause = new Exception();
    final AtomicReference<Object> valueRef = new AtomicReference<>();
    LoadingCache<Object, Object> cache =
        new AbstractLoadingCache<Object, Object>() {
          @Override
          public Object get(Object key) throws ExecutionException {
            Object v = valueRef.get();

  private Iterable<LoadingCache<Object, Object>> caches() {
    // lots of different ways to configure a LoadingCache
    CacheBuilderFactory factory = cacheFactory();
    return Iterables.transform(
        factory.buildAllPermutations(),
        new Function<CacheBuilder<Object, Object>, LoadingCache<Object, Object>>() {
          @Override

  private Iterable<LoadingCache<Object, Object>> caches() {
    // lots of different ways to configure a LoadingCache
    CacheBuilderFactory factory = cacheFactory();
    return Iterables.transform(
        factory.buildAllPermutations(),
        new Function<CacheBuilder<Object, Object>, LoadingCache<Object, Object>>() {
          @Override

  private Iterable<LoadingCache<Object, Object>> caches() {
    // lots of different ways to configure a LoadingCache
    CacheBuilderFactory factory = cacheFactory();
    return Iterables.transform(
        factory.buildAllPermutations(),
        new Function<CacheBuilder<Object, Object>, LoadingCache<Object, Object>>() {
          @Override

  }

  private Iterable<LoadingCache<Key, String>> caches() {
    CacheBuilderFactory factory = factoryWithAllKeyStrengths();
    return Iterables.transform(
        factory.buildAllPermutations(),
        new Function<CacheBuilder<Object, Object>, LoadingCache<Key, String>>() {
          @Override
          public LoadingCache<Key, String> apply(CacheBuilder<Object, Object> builder) {

  private Iterable<LoadingCache<Object, Object>> caches() {
    // lots of different ways to configure a LoadingCache
    CacheBuilderFactory factory = cacheFactory();
    return Iterables.transform(
        factory.buildAllPermutations(),
        new Function<CacheBuilder<Object, Object>, LoadingCache<Object, Object>>() {
          @Override

    for (int i = 1; i < 1000; i++) {
      LoadingCache<Object, Object> cache = CacheBuilder.newBuilder().maximumSize(i).build(loader);
      assertEquals(i, CacheTesting.getTotalSegmentSize(cache));
    }
  }

  public void testEviction_setMaxSegmentWeight() {
    IdentityLoader<Object> loader = identityLoader();
    for (int i = 1; i < 1000; i++) {
      LoadingCache<Object, Object> cache =

   * constructed {@link LoadingCache} as the delegate.
   *
   * @since 10.0
   */
  public abstract static class SimpleForwardingLoadingCache<K, V>
      extends ForwardingLoadingCache<K, V> {
    private final LoadingCache<K, V> delegate;

    protected SimpleForwardingLoadingCache(LoadingCache<K, V> delegate) {
      this.delegate = Preconditions.checkNotNull(delegate);
    }

   * constructed {@link LoadingCache} as the delegate.
   *
   * @since 10.0
   */
  public abstract static class SimpleForwardingLoadingCache<K, V>
      extends ForwardingLoadingCache<K, V> {
    private final LoadingCache<K, V> delegate;

    protected SimpleForwardingLoadingCache(LoadingCache<K, V> delegate) {
      this.delegate = Preconditions.checkNotNull(delegate);
    }