guava/src/com/google/common/collect/ArrayTable.java
@Override
  public Map<C, V> row(R rowKey) {
    checkNotNull(rowKey);
    Integer rowIndex = rowKeyToIndex.get(rowKey);
    return (rowIndex == null) ? ImmutableMap.<C, V>of() : new Row(rowIndex);
  }
@Override
  public Map<C, V> row(R rowKey) {
    checkNotNull(rowKey);
    Integer rowIndex = rowKeyToIndex.get(rowKey);
    return (rowIndex == null) ? ImmutableMap.<C, V>of() : new Row(rowIndex);
  }
Returns a view of all mappings that have the given row key. If the row key isn't in {@link
#rowKeySet()}, an empty immutable map is returned.

<p>Otherwise, for each column key in {@link #columnKeySet()}, the returned map associates the
column key with the corresponding value in the table. Changes to the returned map will update
the underlying table, and vice versa.

@param rowKey key of row to search for in the table
@return the corresponding map from column keys to values