| java.util.NavigableSet
| NavigableSet | | public interface NavigableSet extends SortedSet<E>(Code) | | 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 accessed and
traversed in either ascending or descending order. The
descendingSet method returns a view of the set with the senses of
all relational and directional methods inverted. The performance of
ascending operations and views is likely to be faster than that of
descending ones. This interface additionally defines methods
pollFirst and
pollLast that return and remove the
lowest and highest element, if one exists, else returning
null . Methods
subSet ,
headSet ,
and
tailSet differ from the like-named
SortedSet methods in accepting additional arguments describing
whether lower and upper bounds are inclusive versus exclusive.
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 .)
Methods
NavigableSet.subSet(Object,Object) subSet(E, E) ,
NavigableSet.headSet(Object) headSet(E) , and
NavigableSet.tailSet(Object) tailSet(E) are specified to return
SortedSet to allow existing
implementations of
SortedSet to be compatibly retrofitted to
implement
NavigableSet , but extensions and implementations
of this interface are encouraged to override these methods to return
NavigableSet .
This interface is a member of the
Java Collections Framework.
author:
Doug Lea
author:
Josh Bloch<
Parameters:
E - > the type of elements maintained by this set
since:
1.6 |
| 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. | | NavigableSet<E> | descendingSet()
Returns a reverse order view of the elements contained in this set.
The descending set is backed by this set, so changes to the set are
reflected in the descending set, and vice-versa. | | 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. | | NavigableSet<E> | headSet(E toElement, boolean inclusive)
Returns a view of the portion of this set whose elements are less than
(or equal to, if
inclusive is true)
toElement . | | SortedSet<E> | headSet(E toElement)
Equivalent to
headSet(toElement, false) . | | 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. | | 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. | | NavigableSet<E> | subSet(E fromElement, boolean fromInclusive, E toElement, boolean toInclusive)
Returns a view of the portion of this set whose elements range from
fromElement to
toElement . | | SortedSet<E> | subSet(E fromElement, E toElement)
Equivalent to
subSet(fromElement, true, toElement, false) . | | NavigableSet<E> | tailSet(E fromElement, boolean inclusive)
Returns a view of the portion of this set whose elements are greater
than (or equal to, if
inclusive is true)
fromElement .
The returned set is backed by this set, so changes in the returned set
are reflected in this set, and vice-versa. | | SortedSet<E> | tailSet(E fromElement)
Equivalent to
tailSet(fromElement, true) . |
| ceiling | | E ceiling(E e)(Code) | | Returns the least element in this set greater than or equal to
the given element, or
null if there is no such element.
Parameters:
e - the value to match the least element greater than or equal to e ,or null if there is no such element
throws:
ClassCastException - if the specified element cannot becompared with the elements currently in the set
throws:
NullPointerException - if the specified element is nulland this set does not permit null elements |
| descendingIterator | | Iterator<E> descendingIterator()(Code) | | Returns an iterator over the elements in this set, in descending order.
Equivalent in effect to
descendingSet().iterator() .
an iterator over the elements in this set, in descending order |
| descendingSet | | NavigableSet<E> descendingSet()(Code) | | Returns a reverse order view of the elements contained in this set.
The descending set is backed by this set, so changes to the set are
reflected in the descending set, and vice-versa. If either set is
modified while an iteration over either set is in progress (except
through the iterator's own
remove operation), the results of
the iteration are undefined.
The returned set has an ordering equivalent to
Collections.reverseOrder(Comparator) Collections.reverseOrder (comparator()).
The expression
s.descendingSet().descendingSet() returns a
view of
s essentially equivalent to
s .
a reverse order view of this set |
| floor | | E floor(E e)(Code) | | Returns the greatest element in this set less than or equal to
the given element, or
null if there is no such element.
Parameters:
e - the value to match the greatest element less than or equal to e ,or null if there is no such element
throws:
ClassCastException - if the specified element cannot becompared with the elements currently in the set
throws:
NullPointerException - if the specified element is nulland this set does not permit null elements |
| headSet | | NavigableSet<E> headSet(E toElement, boolean inclusive)(Code) | | Returns a view of the portion of this set whose elements are less than
(or equal to, if
inclusive is true)
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
IllegalArgumentException on an attempt to insert an element outside its range.
Parameters:
toElement - high endpoint of the returned set
Parameters:
inclusive - true if the high endpointis to be included in the returned view a view of the portion of this set whose elements are less than(or equal to, if inclusive is true) toElement
throws:
ClassCastException - if toElement is not compatiblewith 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 thisexception if toElement cannot be compared to elementscurrently in the set.
throws:
NullPointerException - if toElement is null andthis set does not permit null elements
throws:
IllegalArgumentException - if this set itself has arestricted range, and toElement lies outside thebounds of the range |
| higher | | E higher(E e)(Code) | | Returns the least element in this set strictly greater than the
given element, or
null if there is no such element.
Parameters:
e - the value to match the least element greater than e ,or null if there is no such element
throws:
ClassCastException - if the specified element cannot becompared with the elements currently in the set
throws:
NullPointerException - if the specified element is nulland this set does not permit null elements |
| iterator | | Iterator<E> iterator()(Code) | | Returns an iterator over the elements in this set, in ascending order.
an iterator over the elements in this set, in ascending order |
| lower | | E lower(E e)(Code) | | Returns the greatest element in this set strictly less than the
given element, or
null if there is no such element.
Parameters:
e - the value to match the greatest element less than e ,or null if there is no such element
throws:
ClassCastException - if the specified element cannot becompared with the elements currently in the set
throws:
NullPointerException - if the specified element is nulland this set does not permit null elements |
| pollFirst | | E pollFirst()(Code) | | Retrieves and removes the first (lowest) element,
or returns
null if this set is empty.
the first element, or null if this set is empty |
| pollLast | | E pollLast()(Code) | | Retrieves and removes the last (highest) element,
or returns
null if this set is empty.
the last element, or null if this set is empty |
| subSet | | NavigableSet<E> subSet(E fromElement, boolean fromInclusive, E toElement, boolean toInclusive)(Code) | | Returns a view of the portion of this set whose elements range from
fromElement to
toElement . If
fromElement and
toElement are equal, the returned set is empty unless
fromExclusive and
toExclusive are both true. 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
IllegalArgumentException on an attempt to insert an element outside its range.
Parameters:
fromElement - low endpoint of the returned set
Parameters:
fromInclusive - true if the low endpointis to be included in the returned view
Parameters:
toElement - high endpoint of the returned set
Parameters:
toInclusive - true if the high endpointis to be included in the returned view a view of the portion of this set whose elements range from fromElement , inclusive, to toElement , exclusive
throws:
ClassCastException - if fromElement and toElement cannot be compared to one another using thisset's comparator (or, if the set has no comparator, usingnatural ordering). Implementations may, but are not requiredto, throw this exception if fromElement or toElement cannot be compared to elements currently inthe set.
throws:
NullPointerException - if fromElement or toElement is null and this set doesnot permit null elements
throws:
IllegalArgumentException - if fromElement isgreater than toElement ; or if this set itselfhas a restricted range, and fromElement or toElement lies outside the bounds of the range. |
| tailSet | | NavigableSet<E> tailSet(E fromElement, boolean inclusive)(Code) | | Returns a view of the portion of this set whose elements are greater
than (or equal to, if
inclusive is true)
fromElement .
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
IllegalArgumentException on an attempt to insert an element outside its range.
Parameters:
fromElement - low endpoint of the returned set
Parameters:
inclusive - true if the low endpointis to be included in the returned view a view of the portion of this set whose elements are greaterthan or equal to fromElement
throws:
ClassCastException - if fromElement is not compatiblewith 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 thisexception if fromElement cannot be compared to elementscurrently in the set.
throws:
NullPointerException - if fromElement is nulland this set does not permit null elements
throws:
IllegalArgumentException - if this set itself has arestricted range, and fromElement lies outside thebounds of the range |
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