public Object firstKey() { return isDescending? highestKey() : lowestKey(); }
public Object firstKey() { return isDescending? highestKey() : lowestKey(); }
public Object lastKey() { return isDescending? lowestKey() : highestKey(); }
public Object lastKey() { return isDescending? lowestKey() : highestKey(); }
public Object firstKey() { return isDescending? highestKey() : lowestKey(); }
public Object lastKey() { return isDescending? lowestKey() : highestKey(); }