checkNotDone();
      digest.update(bytes);
    }

    private void checkNotDone() {
      checkState(!done, "Cannot re-use a Hasher after calling hash() on it");
    }

    @Override
    public HashCode hash() {
      checkNotDone();
      done = true;
      return (bytes == digest.getDigestLength())
          ? HashCode.fromBytesNoCopy(digest.digest())

 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 */

package com.google.common.hash;

import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.verifyNoMoreInteractions;
import static org.mockito.Mockito.when;

 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 */

package com.google.common.hash;

import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.verifyNoMoreInteractions;
import static org.mockito.Mockito.when;

import java.nio.charset.Charset;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * An abstract composition of multiple hash functions. {@linkplain #newHasher()} delegates to the
 * {@code Hasher} objects of the delegate hash functions, and in the end, they are used by
 * {@linkplain #makeHash(Hasher[])} that constructs the final {@code HashCode}.
 *
 * @author Dimitris Andreou
 */
@Immutable
@ElementTypesAreNonnullByDefault

   */

  private MultimapBuilder() {}

  private static final int DEFAULT_EXPECTED_KEYS = 8;

  /** Uses a hash table to map keys to value collections. */
  public static MultimapBuilderWithKeys<@Nullable Object> hashKeys() {
    return hashKeys(DEFAULT_EXPECTED_KEYS);
  }

  /**
   * Uses a hash table to map keys to value collections, initialized to expect the specified number
   * of keys.
   *

    try {
      tester.addEquivalenceGroup(group1Item1, group1Item2).test();
    } catch (AssertionFailedError expected) {
      String expectedMessage =
          "the hash (1) of TestObject{group=1, item=1} [group 1, item 1] must be "
              + "equal to the hash (2) of TestObject{group=1, item=2} [group 1, item 2]";
      if (!expected.getMessage().contains(expectedMessage)) {

    try {
      tester.addEquivalenceGroup(group1Item1, group1Item2).test();
    } catch (AssertionFailedError expected) {
      String expectedMessage =
          "the hash (1) of TestObject{group=1, item=1} [group 1, item 1] must be "
              + "equal to the hash (2) of TestObject{group=1, item=2} [group 1, item 2]";
      if (!expected.getMessage().contains(expectedMessage)) {

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.common.hash;

import com.google.caliper.BeforeExperiment;
import com.google.caliper.Benchmark;
import com.google.caliper.Param;
import java.util.Random;
import java.util.zip.Adler32;
import java.util.zip.CRC32;

   * objects per entry.  Instead we use an open-addressed hash table.  This design is basically
   * equivalent to RegularImmutableSet, save that instead of having a hash table containing the
   * elements directly and null for empty positions, we store indices of the keys in the hash table,
   * and ABSENT for empty positions.  We then look up the keys in alternatingKeysAndValues.
   *

   * #entriesDiffering()} of the two instances are equal.
   */
  @Override
  boolean equals(@CheckForNull Object object);

  /**
   * Returns the hash code for this instance. This is defined as the hash code of
   *
   * <pre>{@code
   * Arrays.asList(entriesOnlyOnLeft(), entriesOnlyOnRight(),
   *     entriesInCommon(), entriesDiffering())
   * }</pre>
   */
  @Override
  int hashCode();