src/org/kocakosm/pitaya/util/Comparators.java
public static <T> Comparator<T> reverse(final Comparator<T> comparator)
	{
		Parameters.checkNotNull(comparator);
		return new Comparator<T>()
		{
			@Override
			public int compare(T o1, T o2)
			{
				return -comparator.compare(o1, o2);
			}
		};
	}
public static <T> Comparator<T> reverse(final Comparator<T> comparator)
	{
		Parameters.checkNotNull(comparator);
		return new Comparator<T>()
		{
			@Override
			public int compare(T o1, T o2)
			{
				return -comparator.compare(o1, o2);
			}
		};
	}
Returns a {@code Comparator} that represents the reverse ordering of
the given one. Namely, the returned {@code Comparator} will return
a negative value if the original returns a positive value and,
conversely, will return a positive value if it returns a negative
value.

@param <T> the parameters type of the {@code Comparator}s.
@param comparator the comparator to invert.

@return the inverted {@code Comparator}.

@throws NullPointerException if {@code comparator} is {@code null}.