}

  @WeakOuter
  private final class ColumnKeySet extends TableSet<C> {
    @Override
    public Iterator<C> iterator() {
      return createColumnKeyIterator();
    }

    @Override
    public int size() {
      return Iterators.size(iterator());
    }

    @Override
    public boolean remove(@Nullable Object obj) {

          this::applyToValue);
    }

    @Override
    public Set<R> rowKeySet() {
      return fromTable.rowKeySet();
    }

    @Override
    public Set<C> columnKeySet() {
      return fromTable.columnKeySet();
    }

    @Override
    Collection<V2> createValues() {
      return Collections2.transform(fromTable.values(), function);
    }

    @Override

    }

    @Override
    public Set<R> rowKeySet() {
      return fromTable.rowKeySet();
    }

    @Override
    public Set<C> columnKeySet() {
      return fromTable.columnKeySet();
    }

    @Override
    Collection<V2> createValues() {
      return Collections2.transform(fromTable.values(), function);
    }

    @Override

   * table.rowKeySet()} and the column keys in {@code table.columnKeySet()}. Calling {@link #put}
   * with other keys leads to an {@code IllegalArgumentException}.
   *
   * <p>The ordering of {@code table.rowKeySet()} and {@code table.columnKeySet()} determines the
   * row and column iteration ordering of the returned table.
   *

import java.util.Map;

/**
 * Implementation of {@link Table} using linked hash tables. This guarantees predictable iteration
 * order of the various views.
 *
 * <p>The views returned by {@link #column}, {@link #columnKeySet()}, and {@link #columnMap()} have
 * iterators that don't support {@code remove()}. Otherwise, all optional operations are supported.
 * Null row keys, columns keys, and values are not supported.
 *

import java.util.Map;

/**
 * Implementation of {@link Table} using linked hash tables. This guarantees predictable iteration
 * order of the various views.
 *
 * <p>The views returned by {@link #column}, {@link #columnKeySet()}, and {@link #columnMap()} have
 * iterators that don't support {@code remove()}. Otherwise, all optional operations are supported.
 * Null row keys, columns keys, and values are not supported.
 *

    return Maps.safeContainsKey(columnMap(), columnKey);
  }

  @Override
  public Set<R> rowKeySet() {
    return rowMap().keySet();
  }

  @Override
  public Set<C> columnKeySet() {
    return columnMap().keySet();
  }

  @Override
  public boolean containsValue(@Nullable Object value) {
    for (Map<C, V> row : rowMap().values()) {
      if (row.containsValue(value)) {

            'X');
    assertThat(table.columnKeySet().toString()).isEqualTo("[20, 15, 10, 5, 3, 2, 1]");
  }

  public void testColumnKeySet_empty() {
    table = create();
    assertThat(table.columnKeySet().toString()).isEqualTo("[]");
  }

  public void testColumnKeySet_oneRow() {
    table = create("a", 2, 'X', "a", 1, 'X');
    assertThat(table.columnKeySet().toString()).isEqualTo("[1, 2]");
  }

    Table<String, Integer, Character> transpose = transpose(original);
    original.put(1, "foo", 'a');
    assertThat(transpose.rowKeySet()).isSameInstanceAs(original.columnKeySet());
    assertThat(transpose.columnKeySet()).isSameInstanceAs(original.rowKeySet());
    assertThat(transpose.rowMap()).isSameInstanceAs(original.columnMap());
    assertThat(transpose.columnMap()).isSameInstanceAs(original.rowMap());

  }

  public void testColumn() {
    assertEquals(ImmutableMap.of(), INSTANCE.column(1));
  }

  public void testColumnKeySet() {
    assertEquals(ImmutableSet.of(), INSTANCE.columnKeySet());
  }

  public void testColumnMap() {
    assertEquals(ImmutableMap.of(), INSTANCE.columnMap());
  }

  public void testContains() {
    assertFalse(INSTANCE.contains('a', 1));
  }