TreeSet with lower & upper bounds

gistfile1.java

import java.util.Collection;
import java.util.Comparator;
import java.util.TreeSet;

public class BoundedTreeSet<T> extends TreeSet<T> {
	private T min, max;
	
	public BoundedTreeSet(Comparator<T> comparator, T min, T max) {
		super(comparator);
		this.min = min;
		this.max = max;
	}

	@Override
	public boolean addAll(Collection<? extends T> c) {
		Comparator<? super T> comparator = comparator();
		if (null != comparator && null != min && null != max) {
			boolean changed = false;
			for (T t : c) {
				changed |= add(t);
			}
			return changed;
		} else {
			return super.addAll(c);
		}
	}

	@Override
	public boolean add(T t) {
		Comparator<? super T> comparator = comparator();
		if (null != comparator && null != min && null != max) {
			if (comparator.compare(t, min) < 0) {
				return false;
			}
			if (comparator.compare(t, max) > 0) {
				return false;
			}
		}
		return super.add(t);
	}
}