final Function<F, ? extends T> function;
  final Ordering<T> ordering;

  ByFunctionOrdering(Function<F, ? extends T> function, Ordering<T> ordering) {
    this.function = checkNotNull(function);
    this.ordering = checkNotNull(ordering);
  }

  @Override
  public int compare(@ParametricNullness F left, @ParametricNullness F right) {
    return ordering.compare(function.apply(left), function.apply(right));
  }

   * Enums.getIfPresent(Country.class, countryInput).or(Country.DEFAULT);}
   *
   * @since 12.0
   */
  public static <T extends Enum<T>> Optional<T> getIfPresent(Class<T> enumClass, String value) {
    checkNotNull(enumClass);
    checkNotNull(value);
    return Platform.getEnumIfPresent(enumClass, value);
  }

  @GwtIncompatible // java.lang.ref.WeakReference

   *     helpful predefined constants
   * @return the buffered reader
   */
  public static BufferedReader newReader(File file, Charset charset) throws FileNotFoundException {
    checkNotNull(file);
    checkNotNull(charset);
    return new BufferedReader(new InputStreamReader(new FileInputStream(file), charset));
  }

  /**
   * Returns a buffered writer that writes to a file using the given character set.
   *

      @ParametricNullness E key,
      Comparator<? super E> comparator,
      KeyPresentBehavior presentBehavior,
      KeyAbsentBehavior absentBehavior) {
    checkNotNull(comparator);
    checkNotNull(list);
    checkNotNull(presentBehavior);
    checkNotNull(absentBehavior);
    if (!(list instanceof RandomAccess)) {
      list = new ArrayList<>(list);
    }

  @CheckForNull @LazyInit F function;

  AbstractTransformFuture(ListenableFuture<? extends I> inputFuture, F function) {
    this.inputFuture = checkNotNull(inputFuture);
    this.function = checkNotNull(function);
  }

  @Override
  @SuppressWarnings("CatchingUnchecked") // sneaky checked exception
  public final void run() {

          Function<? super T, ? extends K> keyFunction,
          Function<? super T, ? extends V> valueFunction,
          BinaryOperator<V> mergeFunction) {
    checkNotNull(comparator);
    checkNotNull(keyFunction);
    checkNotNull(valueFunction);
    checkNotNull(mergeFunction);
    return collectingAndThen(
        toMap(keyFunction, valueFunction, mergeFunction, () -> new TreeMap<K, V>(comparator)),

    return getSubMultiset(0, elementSet.headIndex(upperBound, checkNotNull(boundType) == CLOSED));
  }

  @Override
  public ImmutableSortedMultiset<E> tailMultiset(E lowerBound, BoundType boundType) {
    return getSubMultiset(
        elementSet.tailIndex(lowerBound, checkNotNull(boundType) == CLOSED), length);
  }

  ImmutableSortedMultiset<E> getSubMultiset(int from, int to) {

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

package com.google.common.collect;

import static com.google.common.base.Preconditions.checkNotNull;
import static java.util.Collections.singletonList;

import java.util.List;

/**
 * GWT emulated version of {@link SingletonImmutableList}.
 *
 * @author Hayward Chan
 */

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

package com.google.common.util.concurrent;

import static com.google.common.base.Preconditions.checkNotNull;
import static java.util.Objects.requireNonNull;

import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.J2ktIncompatible;
import com.google.errorprone.annotations.CanIgnoreReturnValue;

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

package com.google.common.collect;

import static com.google.common.base.Preconditions.checkNotNull;

import com.google.common.annotations.GwtCompatible;
import java.io.Serializable;
import java.util.Comparator;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;