import java.util.Comparator;
import java.util.Iterator;
import java.util.Map;
import java.util.NavigableSet;
import java.util.NavigableMap;
<BUG>import java.util.Set;
@InterfaceAudience.Private
public abstract class CellFlatMap implements NavigableMap<Cell,Cell> {
private final Comparator<? super Cell> comparator;</BUG>
protected int minCellIdx   = 0;   // the index of the minimal cell (for sub-sets)

import java.util.Comparator;
import java.util.Iterator;
import java.util.Map;
import java.util.NavigableSet;
import java.util.NavigableMap;
import java.util.Set;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
@InterfaceAudience.Private
public abstract class CellFlatMap implements NavigableMap<Cell,Cell> {
private static final Log LOG = LogFactory.getLog(CellFlatMap.class);
private final Comparator<? super Cell> comparator;
protected int minCellIdx   = 0;   // the index of the minimal cell (for sub-sets)
