*/
@GwtCompatible
@ElementTypesAreNonnullByDefault
@SuppressWarnings("Java7ApiChecker")
@IgnoreJRERequirement // Users will use this only if they're already using streams.
public final class MoreCollectors {

  /*
   * TODO(lowasser): figure out if we can convert this to a concurrent AtomicReference-based
   * collector without breaking j2cl?
   */

 * limitations under the License.
 */

package com.google.common.collect;

import static com.google.common.collect.MoreCollectors.onlyElement;
import static com.google.common.collect.MoreCollectors.toOptional;
import static com.google.common.collect.ReflectionFreeAssertThrows.assertThrows;
import static com.google.common.truth.Truth.assertThat;

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

package com.google.common.collect;

import static com.google.common.collect.MoreCollectors.onlyElement;

import com.google.caliper.BeforeExperiment;
import com.google.caliper.Benchmark;
import com.google.caliper.Param;
import com.google.caliper.api.SkipThisScenarioException;
import java.util.ArrayList;

 *
 * <ul>
 *   <li>{@link Collections2}
 *   <li>{@link Comparators}
 *   <li>{@link Iterables}
 *   <li>{@link Iterators}
 *   <li>{@link Lists}
 *   <li>{@link Maps}
 *   <li>{@link MoreCollectors}
 *   <li>{@link Multimaps}
 *   <li>{@link Multisets}
 *   <li>{@link ObjectArrays}
 *   <li>{@link Queues}
 *   <li>{@link Sets}
 *   <li>{@link Streams}
 *   <li>{@link Tables}
 * </ul>
 *

 *
 * <ul>
 *   <li>{@link Collections2}
 *   <li>{@link Comparators}
 *   <li>{@link Iterables}
 *   <li>{@link Iterators}
 *   <li>{@link Lists}
 *   <li>{@link Maps}
 *   <li>{@link MoreCollectors}
 *   <li>{@link Multimaps}
 *   <li>{@link Multisets}
 *   <li>{@link ObjectArrays}
 *   <li>{@link Queues}
 *   <li>{@link Sets}
 *   <li>{@link Streams}
 *   <li>{@link Tables}
 * </ul>
 *

  }

  /**
   * Returns the single element contained in {@code iterable}.
   *
   * <p><b>Java 8+ users:</b> the {@code Stream} equivalent to this method is {@code
   * stream.collect(MoreCollectors.onlyElement())}.
   *
   * @throws NoSuchElementException if the iterable is empty
   * @throws IllegalArgumentException if the iterable contains multiple elements
   */
  @ParametricNullness