Returns a view of the portion of this set whose elements are less than (or equal to, if {@code inclusive} is true) {@code toElement}. The returned set is backed by this set, so changes in the returned set are reflected in this set, and vice-versa. The returned set supports all optional set operations that this set supports.
The returned set will throw an {@code IllegalArgumentException}on an attempt to insert an element outside its range.
@param toElement high endpoint of the returned set
@param inclusive {@code true} if the high endpointis to be included in the returned view
@return a view of the portion of this set whose elements are less than(or equal to, if {@code inclusive} is true) {@code toElement}
@throws ClassCastException if {@code toElement} is not compatiblewith this set's comparator (or, if the set has no comparator, if {@code toElement} does not implement {@link Comparable}). Implementations may, but are not required to, throw this exception if {@code toElement} cannot be compared to elementscurrently in the set.
@throws NullPointerException if {@code toElement} is null andthis set does not permit null elements
@throws IllegalArgumentException if this set itself has arestricted range, and {@code toElement} lies outside thebounds of the range