headSet: The fromElement will be in the subset, while the toElement will not: fromElement
If you want the toElement to be in the subset, you must pass in the next node of the tree, or
a value that is just beyond the element.
If you are using string nodes, you can adding something to the end:
SortedSet headSet = set.headSet(toElement+"\0");
To remove the fromElement in the subset:
SortedSet tailSet = set.tailSet(fromElement+"\0");
To get a set that includes both ends, use:
SortedSet bothEnds = set.subSet(fromElement, toElement+"\0");
Or, for a set that includes neither end, use:
SortedSet neitherEnd = set.subSet(fromElement+"\0", toElement);
import java.util.Arrays;
import java.util.TreeSet;
public class MainClass {
public static void main(String args[]) throws Exception {
String elements[] = { "A", "C", "D", "G", "F" };
TreeSet set = new TreeSet(Arrays.asList(elements));
System.out.println(set.tailSet("C"));
System.out.println(set.headSet("C"));
System.out.println(set.headSet("C\0"));
System.out.println(set.tailSet("C\0"));
System.out.println(set.subSet("C", "F\0"));
System.out.println(set.subSet("C", "C\0"));
System.out.println(set.subSet("C", "C"));
}
}
[C, D, F, G]
[A]
[A, C]
[D, F, G]
[C, D, F]
[C]
[]
While displaying elements in an easily sorted manner is nice, if you don't need the behavior,
the cost to add elements and search for them is not worth it.