* undocumented and subject to change.
   */
  public static <R, C, V> ImmutableTable<R, C, V> copyOf(
      Table<? extends R, ? extends C, ? extends V> table) {
    if (table instanceof ImmutableTable) {
      @SuppressWarnings("unchecked")
      ImmutableTable<R, C, V> parameterizedTable = (ImmutableTable<R, C, V>) table;
      return parameterizedTable;
    } else {
      return copyOf(table.cellSet());

   * undocumented and subject to change.
   */
  public static <R, C, V> ImmutableTable<R, C, V> copyOf(
      Table<? extends R, ? extends C, ? extends V> table) {
    if (table instanceof ImmutableTable) {
      @SuppressWarnings("unchecked")
      ImmutableTable<R, C, V> parameterizedTable = (ImmutableTable<R, C, V>) table;
      return parameterizedTable;
    } else {
      return copyOf(table.cellSet());

 *
 * @author Gregory Kick
 */
@GwtCompatible
@NullMarked
public class EmptyImmutableTableTest extends AbstractImmutableTableTest {
  private static final ImmutableTable<Character, Integer, String> INSTANCE = ImmutableTable.of();

  @Override
  Iterable<ImmutableTable<Character, Integer, String>> getTestInstances() {
    return ImmutableSet.of(INSTANCE);
  }

  public void testHashCode() {
    assertEquals(0, INSTANCE.hashCode());

      new DenseImmutableTable<>(CELLS.asList(), ROW_SPACE, COLUMN_SPACE);

  @Override
  Iterable<ImmutableTable<Character, Integer, String>> getTestInstances() {
    return ImmutableList.<ImmutableTable<Character, Integer, String>>of(SPARSE, DENSE);
  }

  public void testCellSet() {
    for (ImmutableTable<Character, Integer, String> testInstance : getTestInstances()) {
      assertEquals(CELLS, testInstance.cellSet());
    }

import com.google.common.annotations.J2ktIncompatible;
import java.util.Map;

/**
 * An implementation of {@link ImmutableTable} that holds a single cell.
 *
 * @author Gregory Kick
 */
@GwtCompatible
final class SingletonImmutableTable<R, C, V> extends ImmutableTable<R, C, V> {
  final R singleRowKey;
  final C singleColumnKey;
  final V singleValue;

          .put(BiMap.class, ImmutableBiMap.of())
          .put(ImmutableBiMap.class, ImmutableBiMap.of())
          .put(Table.class, ImmutableTable.of())
          .put(ImmutableTable.class, ImmutableTable.of())
          .put(RowSortedTable.class, Tables.unmodifiableRowSortedTable(TreeBasedTable.create()))
          .put(ClassToInstanceMap.class, ImmutableClassToInstanceMap.builder().build())

  }

  public void testEqualsObject() {
    new EqualsTester()
        .addEqualityGroup(testTable, HashBasedTable.create(testTable))
        .addEqualityGroup(ImmutableTable.of(), HashBasedTable.create())
        .addEqualityGroup(HashBasedTable.create(ImmutableTable.of('A', 2, "")))
        .testEquals();
  }

  @GwtIncompatible // ArrayTable
  public void testEqualsObjectNullValues() {
    new EqualsTester()

    assertTrue(ArbitraryInstances.get(SortedSetMultimap.class).isEmpty());
    assertEquals(ImmutableTable.of(), ArbitraryInstances.get(Table.class));
    assertEquals(ImmutableTable.of(), ArbitraryInstances.get(ImmutableTable.class));
    assertTrue(ArbitraryInstances.get(RowSortedTable.class).isEmpty());
    assertEquals(ImmutableBiMap.of(), ArbitraryInstances.get(BiMap.class));

        if (contents.isEmpty()) {
          return ImmutableTable.of();
        } else {
          return ArrayTable.create(contents);
        }
      }
    },
    ImmutableTableImpl {
      @Override
      <R extends Comparable<R>, C extends Comparable<C>, V> Table<R, C, V> create(
          Table<R, C, V> contents) {
        return ImmutableTable.copyOf(contents);
      }
    };

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

/**
 * An implementation of {@link ImmutableTable} holding an arbitrary number of cells.
 *
 * @author Gregory Kick
 */
@GwtCompatible
abstract class RegularImmutableTable<R, C, V> extends ImmutableTable<R, C, V> {
  RegularImmutableTable() {}

  abstract Cell<R, C, V> getCell(int iterationIndex);

  @Override