Interface SortedSet<E>
- Type Parameters:
- E- the type of elements maintained by this set
- All Superinterfaces:
- Collection<E>,- Iterable<E>,- SequencedCollection<E>,- SequencedSet<E>,- Set<E>
- All Known Subinterfaces:
- NavigableSet<E>
- All Known Implementing Classes:
- ConcurrentSkipListSet,- TreeSet
Set that further provides a total ordering on its elements.
 The elements are ordered using their natural
 ordering, 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 open range (which contains neither endpoint). The following idiom obtains a view containing all of the Strings in
s from low to
 high, exclusive:SortedSet<String> sub = s.subSet(low+"\0", high);
This interface is a member of the Java Collections Framework.
- Since:
- 1.2
- See Also:
- 
Method SummaryModifier and TypeMethodDescriptiondefault voidThrowsUnsupportedOperationException.default voidThrowsUnsupportedOperationException.Comparator<? super E> Returns the comparator used to order the elements in this set, ornullif this set uses the natural ordering of its elements.first()Returns the first (lowest) element currently in this set.default EgetFirst()Gets the first element of this collection.default EgetLast()Gets the last element of this collection.Returns a view of the portion of this set whose elements are strictly less thantoElement.last()Returns the last (highest) element currently in this set.default ERemoves and returns the first element of this collection (optional operation).default ERemoves and returns the last element of this collection (optional operation).reversed()Returns a reverse-ordered view of this collection.default Spliterator<E> Creates aSpliteratorover the elements in this sorted set.Returns a view of the portion of this set whose elements range fromfromElement, inclusive, totoElement, exclusive.Returns a view of the portion of this set whose elements are greater than or equal tofromElement.Methods declared in interface java.util.CollectionparallelStream, removeIf, stream, toArray
- 
Method Details- 
comparatorComparator<? super E> comparator()Returns the comparator used to order the elements in this set, ornullif this set uses the natural ordering of its elements.- Returns:
- the comparator used to order the elements in this set,
         or nullif this set uses the natural ordering of its elements
 
- 
subSetReturns a view of the portion of this set whose elements range fromfromElement, inclusive, totoElement, exclusive. (IffromElementandtoElementare equal, the returned set is empty.) 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 IllegalArgumentExceptionon an attempt to insert an element outside its range.- Parameters:
- fromElement- low endpoint (inclusive) of the returned set
- toElement- high endpoint (exclusive) of the returned set
- Returns:
- a view of the portion of this set whose elements range from
         fromElement, inclusive, totoElement, exclusive
- Throws:
- ClassCastException- if- fromElementand- toElementcannot 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- fromElementor- toElementcannot be compared to elements currently in the set.
- NullPointerException- if- fromElementor- toElementis null and this set does not permit null elements
- IllegalArgumentException- if- fromElementis greater than- toElement; or if this set itself has a restricted range, and- fromElementor- toElementlies outside the bounds of the range
 
- 
headSetReturns a view of the portion of this set whose elements are strictly less thantoElement. 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 IllegalArgumentExceptionon an attempt to insert an element outside its range.- Parameters:
- toElement- high endpoint (exclusive) of the returned set
- Returns:
- a view of the portion of this set whose elements are strictly
         less than toElement
- Throws:
- ClassCastException- if- toElementis not compatible with this set's comparator (or, if the set has no comparator, if- toElementdoes not implement- Comparable). Implementations may, but are not required to, throw this exception if- toElementcannot be compared to elements currently in the set.
- NullPointerException- if- toElementis null and this set does not permit null elements
- IllegalArgumentException- if this set itself has a restricted range, and- toElementlies outside the bounds of the range
 
- 
tailSetReturns a view of the portion of this set whose elements are greater than or equal tofromElement. 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 IllegalArgumentExceptionon an attempt to insert an element outside its range.- Parameters:
- fromElement- low endpoint (inclusive) of the returned set
- Returns:
- a view of the portion of this set whose elements are greater
         than or equal to fromElement
- Throws:
- ClassCastException- if- fromElementis not compatible with this set's comparator (or, if the set has no comparator, if- fromElementdoes not implement- Comparable). Implementations may, but are not required to, throw this exception if- fromElementcannot be compared to elements currently in the set.
- NullPointerException- if- fromElementis null and this set does not permit null elements
- IllegalArgumentException- if this set itself has a restricted range, and- fromElementlies outside the bounds of the range
 
- 
firstE first()Returns the first (lowest) element currently in this set.- Returns:
- the first (lowest) element currently in this set
- Throws:
- NoSuchElementException- if this set is empty
 
- 
lastE last()Returns the last (highest) element currently in this set.- Returns:
- the last (highest) element currently in this set
- Throws:
- NoSuchElementException- if this set is empty
 
- 
spliteratorCreates aSpliteratorover the elements in this sorted set.The SpliteratorreportsSpliterator.DISTINCT,Spliterator.SORTEDandSpliterator.ORDERED. Implementations should document the reporting of additional characteristic values.The spliterator's comparator (see Spliterator.getComparator()) must benullif the sorted set's comparator (seecomparator()) isnull. Otherwise, the spliterator's comparator must be the same as or impose the same total ordering as the sorted set's comparator.- Specified by:
- spliteratorin interface- Collection<E>
- Specified by:
- spliteratorin interface- Iterable<E>
- Specified by:
- spliteratorin interface- Set<E>
- Implementation Requirements:
- The default implementation creates a
 late-binding spliterator
 from the sorted set's Iterator. The spliterator inherits the fail-fast properties of the set's iterator. The spliterator's comparator is the same as the sorted set's comparator.The created Spliteratoradditionally reportsSpliterator.SIZED.
- Implementation Note:
- The created Spliteratoradditionally reportsSpliterator.SUBSIZED.
- Returns:
- a Spliteratorover the elements in this sorted set
- Since:
- 1.8
 
- 
addFirstThrowsUnsupportedOperationException. The encounter order induced by this set's comparison method determines the position of elements, so explicit positioning is not supported.- Specified by:
- addFirstin interface- SequencedCollection<E>
- Implementation Requirements:
- The implementation in this interface always throws UnsupportedOperationException.
- Parameters:
- e- the element to be added
- Throws:
- UnsupportedOperationException- always
- Since:
- 21
 
- 
addLastThrowsUnsupportedOperationException. The encounter order induced by this set's comparison method determines the position of elements, so explicit positioning is not supported.- Specified by:
- addLastin interface- SequencedCollection<E>
- Implementation Requirements:
- The implementation in this interface always throws UnsupportedOperationException.
- Parameters:
- e- the element to be added.
- Throws:
- UnsupportedOperationException- always
- Since:
- 21
 
- 
getFirstGets the first element of this collection.- Specified by:
- getFirstin interface- SequencedCollection<E>
- Implementation Requirements:
- The implementation in this interface returns the result of calling the firstmethod.
- Returns:
- the retrieved element
- Throws:
- NoSuchElementException- if this collection is empty
- Since:
- 21
 
- 
getLastGets the last element of this collection.- Specified by:
- getLastin interface- SequencedCollection<E>
- Implementation Requirements:
- The implementation in this interface returns the result of calling the lastmethod.
- Returns:
- the retrieved element
- Throws:
- NoSuchElementException- if this collection is empty
- Since:
- 21
 
- 
removeFirstRemoves and returns the first element of this collection (optional operation).- Specified by:
- removeFirstin interface- SequencedCollection<E>
- Implementation Requirements:
- The implementation in this interface calls the firstmethod to obtain the first element, then it callsremove(element)to remove the element, and then it returns the element.
- Returns:
- the removed element
- Throws:
- NoSuchElementException- if this collection is empty
- UnsupportedOperationException- if this collection implementation does not support this operation
- Since:
- 21
 
- 
removeLastRemoves and returns the last element of this collection (optional operation).- Specified by:
- removeLastin interface- SequencedCollection<E>
- Implementation Requirements:
- The implementation in this interface calls the lastmethod to obtain the last element, then it callsremove(element)to remove the element, and then it returns the element.
- Returns:
- the removed element
- Throws:
- NoSuchElementException- if this collection is empty
- UnsupportedOperationException- if this collection implementation does not support this operation
- Since:
- 21
 
- 
reversedReturns a reverse-ordered view of this collection. The encounter order of elements in the returned view is the inverse of the encounter order of elements in this collection. The reverse ordering affects all order-sensitive operations, including those on the view collections of the returned view. If the collection implementation permits modifications to this view, the modifications "write through" to the underlying collection. Changes to the underlying collection might or might not be visible in this reversed view, depending upon the implementation.- Specified by:
- reversedin interface- SequencedCollection<E>
- Specified by:
- reversedin interface- SequencedSet<E>
- Implementation Requirements:
- The implementation in this interface returns a reverse-ordered SortedSet
 view. The reversed()method of the view returns a reference to this SortedSet. Other operations on the view are implemented via calls to public methods on this SortedSet. The exact relationship between calls on the view and calls on this SortedSet is unspecified. However, order-sensitive operations generally behave as if they delegate to the appropriate method with the opposite orientation. For example, callinggetFirston the view might result in a call togetLaston this SortedSet.
- Returns:
- a reverse-ordered view of this collection, as a SortedSet
- Since:
- 21
 
 
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