* @since 11.0
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public interface Weigher<K, V> {

  /**
   * Returns the weight of a cache entry. There is no unit for entry weights; rather they are simply
   * relative to each other.
   *
   * @return the weight of the entry; must be non-negative
   */
  int weigh(K key, V value);

                    return (Map) builder.build();
                  }
                })
            .named("ImmutableTypeToInstanceMap")
            .withFeatures(
                MapFeature.REJECTS_DUPLICATES_AT_CREATION,
                MapFeature.RESTRICTS_KEYS,
                CollectionFeature.KNOWN_ORDER,
                CollectionSize.ANY,
                MapFeature.ALLOWS_ANY_NULL_QUERIES)
            .createTestSuite());

  @CollectionFeature.Require({ALLOWS_NULL_VALUES, REJECTS_DUPLICATES_AT_CREATION})
  @CollectionSize.Require(absent = {ZERO, ONE})
  public void testCreateWithDuplicates_nullDuplicatesRejected() {
    E[] array = createArrayWithNullElement();
    array[0] = null;
    try {
      collection = getSubjectGenerator().create(array);
      fail("Should reject duplicate null elements at creation");
    } catch (IllegalArgumentException expected) {
    }
  }

 * limitations under the License.
 */

package com.google.common.collect.testing.testers;

import static com.google.common.collect.testing.features.CollectionFeature.REJECTS_DUPLICATES_AT_CREATION;
import static com.google.common.collect.testing.features.CollectionSize.ONE;
import static com.google.common.collect.testing.features.CollectionSize.ZERO;

import com.google.common.annotations.GwtCompatible;

 * limitations under the License.
 */

package com.google.common.collect.testing.testers;

import static com.google.common.collect.testing.features.CollectionFeature.REJECTS_DUPLICATES_AT_CREATION;
import static com.google.common.collect.testing.features.CollectionSize.ONE;
import static com.google.common.collect.testing.features.CollectionSize.ZERO;

import com.google.common.annotations.GwtCompatible;

        });
    assertTrue(1 >= cache.size());
  }

  public void testCompute() {
    cache.put(key, "1");
    // simultaneous deletion
    doParallelCacheOp(
        count,
        n -> {
          cache.asMap().compute(key, (k, v) -> null);
        });
    assertEquals(0, cache.size());
  }

  public void testComputeWithLoad() {

    }

    inverseFeatures.add(NoRecurse.INVERSE);
    inverseFeatures.remove(CollectionFeature.KNOWN_ORDER);
    inverseFeatures.add(MapFeature.REJECTS_DUPLICATES_AT_CREATION);

    return inverseFeatures;
  }

  // TODO(lowasser): can we eliminate the duplication from MapTestSuiteBuilder here?

import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.testing.SampleElements.Strings;
import java.util.Collection;
import java.util.List;

/**
 * String creation for testing arbitrary collections.
 *
 * @author Jared Levy
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public abstract class TestStringCollectionGenerator implements TestCollectionGenerator<String> {

 *
 * @author Dimitris Andreou
 */
@Immutable
@ElementTypesAreNonnullByDefault
abstract class AbstractCompositeHashFunction extends AbstractHashFunction {

  @SuppressWarnings("Immutable") // array not modified after creation
  final HashFunction[] functions;

  AbstractCompositeHashFunction(HashFunction... functions) {
    for (HashFunction function : functions) {
      checkNotNull(function);
    }
    this.functions = functions;

   * throws an {@link IllegalArgumentException} when presented with duplicate elements instead of
   * collapsing them to a single element or including duplicate instances in the collection.
   */
  REJECTS_DUPLICATES_AT_CREATION,

  SUPPORTS_ADD,
  SUPPORTS_REMOVE,
  SUPPORTS_ITERATOR_REMOVE,
  FAILS_FAST_ON_CONCURRENT_MODIFICATION,

  /**