E - the type of elements maintained by this setpublic interface NavigableSet<E>
A SortedSet extended with navigation methods reporting
closest matches for given search targets. Methods lower,
floor, ceiling, and higher return elements
respectively less than, less than or equal, greater than or equal,
and greater than a given element, returning null if there is
no such element. A NavigableSet may be viewed and traversed
in either ascending or descending order. The Collection
iterator method returns an ascending Iterator and
the additional method descendingIterator returns a
descending iterator. The performance of ascending traversals is
likely to be faster than descending traversals. This interface
additionally defines methods pollFirst and
pollLast that return and remove the lowest and highest
element, if one exists, else returning null.
Methods navigableSubSet, navigableHeadSet, and
navigableTailSet differ from the similarly named
SortedSet methods only in their declared return types.
Subsets of any NavigableSet must implement the
NavigableSet interface.
The return values of navigation methods may be ambiguous in
implementations that permit null elements. However, even
in this case the result can be disambiguated by checking
contains(null). To avoid such issues, implementations of
this interface are encouraged to not permit insertion of
null elements. (Note that sorted sets of Comparable elements intrinsically do not permit null.)
This interface is a member of the Java Collections Framework.
| Method Summary | |
|---|---|
E |
ceiling(E e)
Returns the least element in this set greater than or equal to the given element, or null if there is no such element. |
Iterator<E> |
descendingIterator()
Returns an iterator over the elements in this set, in descending order. |
E |
floor(E e)
Returns the greatest element in this set less than or equal to the given element, or null if there is no such element. |
E |
higher(E e)
Returns the least element in this set strictly greater than the given element, or null if there is no such element. |
Iterator<E> |
iterator()
Returns an iterator over the elements in this set, in ascending order. |
E |
lower(E e)
Returns the greatest element in this set strictly less than the given element, or null if there is no such element. |
NavigableSet<E> |
navigableHeadSet(E toElement)
Returns a view of the portion of this set whose elements are strictly less than toElement. |
NavigableSet<E> |
navigableSubSet(E fromElement,
E toElement)
Returns a view of the portion of this set whose elements range from fromElement, inclusive, to toElement, exclusive. |
NavigableSet<E> |
navigableTailSet(E fromElement)
Returns a view of the portion of this set whose elements are greater than or equal to fromElement. |
E |
pollFirst()
Retrieves and removes the first (lowest) element, or returns null if this set is empty. |
E |
pollLast()
Retrieves and removes the last (highest) element, or returns null if this set is empty. |
| Methods inherited from interface java.util.SortedSet |
|---|
comparator, first, headSet, last, subSet, tailSet |
| Methods inherited from interface java.util.Set |
|---|
add, addAll, clear, contains, containsAll, equals, hashCode, isEmpty, remove, removeAll, retainAll, size, toArray, toArray |
| Method Detail |
|---|
E lower(E e)
e - the value to match
ClassCastException - if the specified element cannot be
compared with the elements currently in the set
NullPointerException - if the specified element is null
and this set does not permit null elementsE floor(E e)
e - the value to match
ClassCastException - if the specified element cannot be
compared with the elements currently in the set
NullPointerException - if the specified element is null
and this set does not permit null elementsE ceiling(E e)
e - the value to match
ClassCastException - if the specified element cannot be
compared with the elements currently in the set
NullPointerException - if the specified element is null
and this set does not permit null elementsE higher(E e)
e - the value to match
ClassCastException - if the specified element cannot be
compared with the elements currently in the set
NullPointerException - if the specified element is null
and this set does not permit null elementsE pollFirst()
E pollLast()
Iterator<E> iterator()
iterator in interface Collection<E>iterator in interface Iterable<E>iterator in interface Set<E>Iterator<E> descendingIterator()
NavigableSet<E> navigableSubSet(E fromElement,
E toElement)
The returned set will throw an IllegalArgumentException on an attempt to insert an element outside its range.
fromElement - low endpoint (inclusive) of the returned settoElement - high endpoint (exclusive) of the returned set
ClassCastException - if fromElement and
toElement cannot be compared to one another using this
set's comparator (or, if the set has no comparator, using
natural ordering). Implementations may, but are not required
to, throw this exception if fromElement or
toElement cannot be compared to elements currently in
the set.
NullPointerException - if fromElement or
toElement is null and this set does
not permit null elements
IllegalArgumentException - if fromElement is
greater than toElement; or if this set itself
has a restricted range, and fromElement or
toElement lies outside the bounds of the range.NavigableSet<E> navigableHeadSet(E toElement)
The returned set will throw an IllegalArgumentException on an attempt to insert an element outside its range.
toElement - high endpoint (exclusive) of the returned set
ClassCastException - if toElement is not compatible
with this set's comparator (or, if the set has no comparator,
if toElement does not implement Comparable).
Implementations may, but are not required to, throw this
exception if toElement cannot be compared to elements
currently in the set.
NullPointerException - if toElement is null and
this set does not permit null elements
IllegalArgumentException - if this set itself has a
restricted range, and toElement lies outside the
bounds of the rangeNavigableSet<E> navigableTailSet(E fromElement)
The returned set will throw an IllegalArgumentException on an attempt to insert an element outside its range.
fromElement - low endpoint (inclusive) of the returned set
ClassCastException - if fromElement is not compatible
with this set's comparator (or, if the set has no comparator,
if fromElement does not implement Comparable).
Implementations may, but are not required to, throw this
exception if fromElement cannot be compared to elements
currently in the set.
NullPointerException - if fromElement is null
and this set does not permit null elements
IllegalArgumentException - if this set itself has a
restricted range, and fromElement lies outside the
bounds of the range