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SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD |
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 | |
---|---|
java.lang.Object |
ceiling(java.lang.Object e)
Returns the least element in this set greater than or equal to the given element, or null if there is no such element. |
java.util.Iterator |
descendingIterator()
Returns an iterator over the elements in this set, in descending order. |
java.lang.Object |
floor(java.lang.Object e)
Returns the greatest element in this set less than or equal to the given element, or null if there is no such element. |
java.lang.Object |
higher(java.lang.Object e)
Returns the least element in this set strictly greater than the given element, or null if there is no such element. |
java.util.Iterator |
iterator()
Returns an iterator over the elements in this set, in ascending order. |
java.lang.Object |
lower(java.lang.Object e)
Returns the greatest element in this set strictly less than the given element, or null if there is no such element. |
NavigableSet |
navigableHeadSet(java.lang.Object toElement)
Returns a view of the portion of this set whose elements are strictly less than toElement. |
NavigableSet |
navigableSubSet(java.lang.Object fromElement,
java.lang.Object toElement)
Returns a view of the portion of this set whose elements range from fromElement, inclusive, to toElement, exclusive. |
NavigableSet |
navigableTailSet(java.lang.Object fromElement)
Returns a view of the portion of this set whose elements are greater than or equal to fromElement. |
java.lang.Object |
pollFirst()
Retrieves and removes the first (lowest) element, or returns null if this set is empty. |
java.lang.Object |
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 |
public java.lang.Object lower(java.lang.Object e)
e
- the value to match
java.lang.ClassCastException
- if the specified element cannot be
compared with the elements currently in the set
java.lang.NullPointerException
- if the specified element is null
and this set does not permit null elementspublic java.lang.Object floor(java.lang.Object e)
e
- the value to match
java.lang.ClassCastException
- if the specified element cannot be
compared with the elements currently in the set
java.lang.NullPointerException
- if the specified element is null
and this set does not permit null elementspublic java.lang.Object ceiling(java.lang.Object e)
e
- the value to match
java.lang.ClassCastException
- if the specified element cannot be
compared with the elements currently in the set
java.lang.NullPointerException
- if the specified element is null
and this set does not permit null elementspublic java.lang.Object higher(java.lang.Object e)
e
- the value to match
java.lang.ClassCastException
- if the specified element cannot be
compared with the elements currently in the set
java.lang.NullPointerException
- if the specified element is null
and this set does not permit null elementspublic java.lang.Object pollFirst()
public java.lang.Object pollLast()
public java.util.Iterator iterator()
iterator
in interface java.util.Set
public java.util.Iterator descendingIterator()
public NavigableSet navigableSubSet(java.lang.Object fromElement, java.lang.Object 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
java.lang.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.
java.lang.NullPointerException
- if fromElement or
toElement is null and this set does
not permit null elements
java.lang.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.public NavigableSet navigableHeadSet(java.lang.Object 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
java.lang.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.
java.lang.NullPointerException
- if toElement is null and
this set does not permit null elements
java.lang.IllegalArgumentException
- if this set itself has a
restricted range, and toElement lies outside the
bounds of the rangepublic NavigableSet navigableTailSet(java.lang.Object 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
java.lang.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.
java.lang.NullPointerException
- if fromElement is null
and this set does not permit null elements
java.lang.IllegalArgumentException
- if this set itself has a
restricted range, and fromElement lies outside the
bounds of the range
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