import java.util.Set;
import org.jspecify.annotations.Nullable;

/**
 * An empty contiguous set.
 *
 * @author Gregory Kick
 */
@GwtCompatible
@SuppressWarnings("rawtypes") // allow ungenerified Comparable types
final class EmptyContiguousSet<C extends Comparable> extends ContiguousSet<C> {
  EmptyContiguousSet(DiscreteDomain<C> domain) {
    super(domain);
  }

  @Override
  public C first() {

 * Collections#frequency}) can cause major performance problems.
 *
 * @author Gregory Kick
 * @since 10.0
 */
@GwtCompatible
@SuppressWarnings("rawtypes") // allow ungenerified Comparable types
public abstract class ContiguousSet<C extends Comparable> extends ImmutableSortedSet<C> {
  /**
   * Returns a {@code ContiguousSet} containing the same values in the given domain {@linkplain

 * Collections#frequency}) can cause major performance problems.
 *
 * @author Gregory Kick
 * @since 10.0
 */
@GwtCompatible
@SuppressWarnings("rawtypes") // allow ungenerified Comparable types
public abstract class ContiguousSet<C extends Comparable> extends ImmutableSortedSet<C> {
  /**
   * Returns a {@code ContiguousSet} containing the same values in the given domain {@linkplain

 *       undefined horrible things to happen in {@code Range}. For now, the Range API does not
 *       prevent its use, because this would also rule out all ungenerified (pre-JDK1.5) data types.
 *       <b>This may change in the future.</b>
 * </ul>
 *
 * <h3>Other notes</h3>
 *
 * <ul>
 *   <li>All ranges are shallow-immutable.