public abstract interface SortedSet <E>

A `Set`

that further provides a *total ordering* on its elements.
The elements are ordered using their natural, or by a `Comparator`

typically provided at sorted
set creation time. The set's iterator will traverse the set in
ascending element order. Several additional operations are provided
to take advantage of the ordering. (This interface is the set
analogue of `SortedMap`

.)

All elements inserted into a sorted set must implement the `Comparable`
interface (or be accepted by the specified comparator). Furthermore, all
such elements must be *mutually comparable*: `e1.compareTo(e2)`
(or `comparator.compare(e1, e2)`) must not throw a
`ClassCastException` for any elements `e1` and `e2` in
the sorted set. Attempts to violate this restriction will cause the
offending method or constructor invocation to throw a
`ClassCastException`.

Note that the ordering maintained by a sorted set (whether or not an
explicit comparator is provided) must be *consistent with equals* if
the sorted set is to correctly implement the `Set` interface. (See
the `Comparable` interface or `Comparator` interface for a
precise definition of *consistent with equals*.) This is so because
the `Set` interface is defined in terms of the `equals`
operation, but a sorted set performs all element comparisons using its
`compareTo` (or `compare`) method, so two elements that are
deemed equal by this method are, from the standpoint of the sorted set,
equal. The behavior of a sorted set *is* well-defined even if its
ordering is inconsistent with equals; it just fails to obey the general
contract of the `Set` interface.

All general-purpose sorted set implementation classes should
provide four "standard" constructors: 1) A void (no arguments)
constructor, which creates an empty sorted set sorted according to
the natural ordering of its elements. 2) A constructor with a
single argument of type `Comparator`, which creates an empty
sorted set sorted according to the specified comparator. 3) A
constructor with a single argument of type `Collection`,
which creates a new sorted set with the same elements as its
argument, sorted according to the natural ordering of the elements.
4) A constructor with a single argument of type `SortedSet`,
which creates a new sorted set with the same elements and the same
ordering as the input sorted set. There is no way to enforce this
recommendation, as interfaces cannot contain constructors.

Note: several methods return subsets with restricted ranges.
Such ranges are *half-open*, that is, they include their low
endpoint but not their high endpoint (where applicable).
If you need a *closed range* (which includes both endpoints), and
the element type allows for calculation of the successor of a given
value, merely request the subrange from `lowEndpoint` to
`successor(highEndpoint)`. For example, suppose that `s`
is a sorted set of strings. The following idiom obtains a view
containing all of the strings in `s` from `low` to
`high`, inclusive:

SortedSet<String> sub = s.subSet(low, high+"\0");A similar technique can be used to generate an

SortedSet<String> sub = s.subSet(low+"\0", high);

This interface is a member of the Java Collections Framework.

**extends**

`<E>` | the type of elements maintained by this set |

Set, TreeSet, SortedMap, Collection, Comparable, Comparator, ClassCastException