TreeSet

java.lang.Object
- java.util.AbstractCollection<E>
- - java.util.AbstractSet<E>
  - - java.util.TreeSet<E>

类型参数:

E - the type of elements maintained by this set

所有已实现的接口:

Serializable, Cloneable, Iterable<E>, Collection<E>, NavigableSet<E>, Set<E>, SortedSet<E>
```
public class TreeSet<E>
extends AbstractSet<E>
implements NavigableSet<E>, Cloneable, Serializable
```
A NavigableSet implementation based on a TreeMap. The elements are ordered using their Comparable, or by a Comparator provided at set creation time, depending on which constructor is used.
This implementation provides guaranteed log(n) time cost for the basic operations (add, remove and contains).
Note that the ordering maintained by a set (whether or not an explicit comparator is provided) must be consistent with equals if it is to correctly implement the Set interface. (See Comparable or Comparator 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 TreeSet instance 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 set, equal. The behavior of a set is well-defined even if its ordering is inconsistent with equals; it just fails to obey the general contract of the Set interface.
Note that this implementation is not synchronized. If multiple threads access a tree set concurrently, and at least one of the threads modifies the set, it must be synchronized externally. This is typically accomplished by synchronizing on some object that naturally encapsulates the set. If no such object exists, the set should be "wrapped" using the Collections#synchronizedSortedSet method. This is best done at creation time, to prevent accidental unsynchronized access to the set:
```
   SortedSet s = Collections.synchronizedSortedSet(new TreeSet(...));
```
The iterators returned by this class's iterator method are fail-fast: if the set is modified at any time after the iterator is created, in any way except through the iterator's own remove method, the iterator will throw a ConcurrentModificationException. Thus, in the face of concurrent modification, the iterator fails quickly and cleanly, rather than risking arbitrary, non-deterministic behavior at an undetermined time in the future.
Note that the fail-fast behavior of an iterator cannot be guaranteed as it is, generally speaking, impossible to make any hard guarantees in the presence of unsynchronized concurrent modification. Fail-fast iterators throw ConcurrentModificationException on a best-effort basis. Therefore, it would be wrong to write a program that depended on this exception for its correctness: the fail-fast behavior of iterators should be used only to detect bugs.
This class is a member of the Java Collections Framework.
从以下版本开始:

1.2

另请参阅:

Collection, Set, HashSet, Comparable, Comparator, TreeMap, 序列化表格

构造器概要

构造器
构造器	说明
`TreeSet()`	Constructs a new, empty tree set, sorted according to the natural ordering of its elements.
`TreeSet(Collection<? extends E> c)`	Constructs a new tree set containing the elements in the specified collection, sorted according to the natural ordering of its elements.
`TreeSet(Comparator<? super E> comparator)`	Constructs a new, empty tree set, sorted according to the specified comparator.
`TreeSet(SortedSet<E> s)`	Constructs a new tree set containing the same elements and using the same ordering as the specified sorted set.

方法概要

所有方法实例方法具体方法
限定符和类型	方法	说明
`boolean`	`add(E e)`	Adds the specified element to this set if it is not already present.
`boolean`	`addAll(Collection<? extends E> c)`	Adds all of the elements in the specified collection to this set.
`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.
`void`	`clear()`	Removes all of the elements from this set.
`Object`	`clone()`	Returns a shallow copy of this `TreeSet` instance.
`Comparator<? super E>`	`comparator()`	Returns the comparator used to order the elements in this set, or `null` if this set uses the Comparable of its elements.
`boolean`	`contains(Object o)`	Returns `true` if this set contains the specified 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.
`E`	`first()`	Returns the first (lowest) element currently in this set.
`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.
`SortedSet<E>`	`headSet(E toElement)`	Returns a view of the portion of this set whose elements are strictly less than `toElement`.
`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`.
`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.
`boolean`	`isEmpty()`	Returns `true` if this set contains no elements.
`Iterator<E>`	`iterator()`	Returns an iterator over the elements in this set in ascending order.
`E`	`last()`	Returns the last (highest) element currently in this set.
`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.
`boolean`	`remove(Object o)`	Removes the specified element from this set if it is present.
`int`	`size()`	Returns the number of elements in this set (its cardinality).
`Spliterator<E>`	`spliterator()`	Creates a late-binding and fail-fast `Spliterator` over the elements in this set.
`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)`	Returns a view of the portion of this set whose elements range from `fromElement`, inclusive, to `toElement`, exclusive.
`SortedSet<E>`	`tailSet(E fromElement)`	Returns a view of the portion of this set whose elements are greater than or equal to `fromElement`.
`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`.

从类继承的方法 java.util.AbstractCollection
containsAll, retainAll, toArray, toArray, toString

从类继承的方法 java.util.AbstractSet
equals, hashCode, removeAll

从接口继承的方法 java.util.Collection
parallelStream, removeIf, stream

从接口继承的方法 java.lang.Iterable
forEach

从类继承的方法 java.lang.Object
finalize, getClass, notify, notifyAll, wait, wait, wait

从接口继承的方法 java.util.Set
containsAll, equals, hashCode, removeAll, retainAll, toArray, toArray

- 构造器详细资料
  - TreeSet
```
public TreeSet()
```
    Constructs a new, empty tree set, sorted according to the natural ordering of its elements. All elements inserted into the set must implement the Comparable interface. Furthermore, all such elements must be mutually comparable: e1.compareTo(e2) must not throw a ClassCastException for any elements e1 and e2 in the set. If the user attempts to add an element to the set that violates this constraint (for example, the user attempts to add a string element to a set whose elements are integers), the add call will throw a ClassCastException.
  - TreeSet
```
public TreeSet(Comparator<? super E> comparator)
```
    Constructs a new, empty tree set, sorted according to the specified comparator. All elements inserted into the set must be mutually comparable by the specified comparator: comparator.compare(e1, e2) must not throw a ClassCastException for any elements e1 and e2 in the set. If the user attempts to add an element to the set that violates this constraint, the add call will throw a ClassCastException.
    
    参数:
    
    comparator - the comparator that will be used to order this set. If null, the Comparable of the elements will be used.
  - TreeSet
```
public TreeSet(Collection<? extends E> c)
```
    Constructs a new tree set containing the elements in the specified collection, sorted according to the natural ordering of its elements. All elements inserted into the set must implement the Comparable interface. Furthermore, all such elements must be mutually comparable: e1.compareTo(e2) must not throw a ClassCastException for any elements e1 and e2 in the set.
    
    参数:
    
    c - collection whose elements will comprise the new set
    
    抛出:
    
    ClassCastException - if the elements in c are not Comparable, or are not mutually comparable
    
    NullPointerException - if the specified collection is null
  - TreeSet
```
public TreeSet(SortedSet<E> s)
```
    Constructs a new tree set containing the same elements and using the same ordering as the specified sorted set.
    
    参数:
    
    s - sorted set whose elements will comprise the new set
    
    抛出:
    
    NullPointerException - if the specified sorted set is null
- 方法详细资料
  - iterator
```
public Iterator<E> iterator()
```
    Returns an iterator over the elements in this set in ascending order.
    
    指定者:
    
    iterator 在接口中 Collection<E>
    
    指定者:
    
    iterator 在接口中 Iterable<E>
    
    指定者:
    
    iterator 在接口中 NavigableSet<E>
    
    指定者:
    
    iterator 在接口中 Set<E>
    
    指定者:
    
    iterator 在类中 AbstractCollection<E>
    
    返回:
    
    an iterator over the elements in this set in ascending order
  - descendingIterator
```
public Iterator<E> descendingIterator()
```
    Returns an iterator over the elements in this set in descending order.
    
    指定者:
    
    descendingIterator 在接口中 NavigableSet<E>
    
    返回:
    
    an iterator over the elements in this set in descending order
    
    从以下版本开始:
    
    1.6
  - descendingSet
```
public NavigableSet<E> descendingSet()
```
    从接口复制的说明: NavigableSet
    
    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)(comparator()). The expression s.descendingSet().descendingSet() returns a view of s essentially equivalent to s.
    
    指定者:
    
    descendingSet 在接口中 NavigableSet<E>
    
    返回:
    
    a reverse order view of this set
    
    从以下版本开始:
    
    1.6
  - size
```
public int size()
```
    Returns the number of elements in this set (its cardinality).
    
    指定者:
    
    size 在接口中 Collection<E>
    
    指定者:
    
    size 在接口中 Set<E>
    
    指定者:
    
    size 在类中 AbstractCollection<E>
    
    返回:
    
    the number of elements in this set (its cardinality)
  - isEmpty
```
public boolean isEmpty()
```
    Returns true if this set contains no elements.
    
    指定者:
    
    isEmpty 在接口中 Collection<E>
    
    指定者:
    
    isEmpty 在接口中 Set<E>
    
    覆盖:
    
    isEmpty 在类中 AbstractCollection<E>
    
    返回:
    
    true if this set contains no elements
  - contains
```
public boolean contains(Object o)
```
    Returns true if this set contains the specified element. More formally, returns true if and only if this set contains an element e such that (o==null ? e==null : o.equals(e)).
    
    指定者:
    
    contains 在接口中 Collection<E>
    
    指定者:
    
    contains 在接口中 Set<E>
    
    覆盖:
    
    contains 在类中 AbstractCollection<E>
    
    参数:
    
    o - object to be checked for containment in this set
    
    返回:
    
    true if this set contains the specified element
    
    抛出:
    
    ClassCastException - if the specified object cannot be compared with the elements currently in the set
    
    NullPointerException - if the specified element is null and this set uses natural ordering, or its comparator does not permit null elements
  - add
```
public boolean add(E e)
```
    Adds the specified element to this set if it is not already present. More formally, adds the specified element e to this set if the set contains no element e2 such that (e==null ? e2==null : e.equals(e2)). If this set already contains the element, the call leaves the set unchanged and returns false.
    
    指定者:
    
    add 在接口中 Collection<E>
    
    指定者:
    
    add 在接口中 Set<E>
    
    覆盖:
    
    add 在类中 AbstractCollection<E>
    
    参数:
    
    e - element to be added to this set
    
    返回:
    
    true if this set did not already contain the specified element
    
    抛出:
    
    ClassCastException - if the specified object cannot be compared with the elements currently in this set
    
    NullPointerException - if the specified element is null and this set uses natural ordering, or its comparator does not permit null elements
  - remove
```
public boolean remove(Object o)
```
    Removes the specified element from this set if it is present. More formally, removes an element e such that (o==null ? e==null : o.equals(e)), if this set contains such an element. Returns true if this set contained the element (or equivalently, if this set changed as a result of the call). (This set will not contain the element once the call returns.)
    
    指定者:
    
    remove 在接口中 Collection<E>
    
    指定者:
    
    remove 在接口中 Set<E>
    
    覆盖:
    
    remove 在类中 AbstractCollection<E>
    
    参数:
    
    o - object to be removed from this set, if present
    
    返回:
    
    true if this set contained the specified element
    
    抛出:
    
    ClassCastException - if the specified object cannot be compared with the elements currently in this set
    
    NullPointerException - if the specified element is null and this set uses natural ordering, or its comparator does not permit null elements
  - clear
```
public void clear()
```
    Removes all of the elements from this set. The set will be empty after this call returns.
    
    指定者:
    
    clear 在接口中 Collection<E>
    
    指定者:
    
    clear 在接口中 Set<E>
    
    覆盖:
    
    clear 在类中 AbstractCollection<E>
  - addAll
```
public boolean addAll(Collection<? extends E> c)
```
    Adds all of the elements in the specified collection to this set.
    
    指定者:
    
    addAll 在接口中 Collection<E>
    
    指定者:
    
    addAll 在接口中 Set<E>
    
    覆盖:
    
    addAll 在类中 AbstractCollection<E>
    
    参数:
    
    c - collection containing elements to be added to this set
    
    返回:
    
    true if this set changed as a result of the call
    
    抛出:
    
    ClassCastException - if the elements provided cannot be compared with the elements currently in the set
    
    NullPointerException - if the specified collection is null or if any element is null and this set uses natural ordering, or its comparator does not permit null elements
    
    另请参阅:
    
    AbstractCollection.add(Object)
  - subSet
```
public NavigableSet<E> subSet(E fromElement,
                              boolean fromInclusive,
                              E toElement,
                              boolean toInclusive)
```
    从接口复制的说明: NavigableSet
    
    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 fromInclusive and toInclusive 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.
    
    指定者:
    
    subSet 在接口中 NavigableSet<E>
    
    参数:
    
    fromElement - low endpoint of the returned set
    
    fromInclusive - true if the low endpoint is to be included in the returned view
    
    toElement - high endpoint of the returned set
    
    toInclusive - true if the high endpoint is to be included in the returned view
    
    返回:
    
    a view of the portion of this set whose elements range from fromElement, inclusive, to toElement, exclusive
    
    抛出:
    
    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 uses natural ordering, or its comparator 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.
    
    从以下版本开始:
    
    1.6
  - headSet
```
public NavigableSet<E> headSet(E toElement,
                               boolean inclusive)
```
    从接口复制的说明: NavigableSet
    
    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.
    
    指定者:
    
    headSet 在接口中 NavigableSet<E>
    
    参数:
    
    toElement - high endpoint of the returned set
    
    inclusive - true if the high endpoint is to be included in the returned view
    
    返回:
    
    a view of the portion of this set whose elements are less than (or equal to, if inclusive is true) toElement
    
    抛出:
    
    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 uses natural ordering, or its comparator does not permit null elements
    
    IllegalArgumentException - if this set itself has a restricted range, and toElement lies outside the bounds of the range
    
    从以下版本开始:
    
    1.6
  - tailSet
```
public NavigableSet<E> tailSet(E fromElement,
                               boolean inclusive)
```
    从接口复制的说明: NavigableSet
    
    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.
    
    指定者:
    
    tailSet 在接口中 NavigableSet<E>
    
    参数:
    
    fromElement - low endpoint of the returned set
    
    inclusive - true if the low endpoint is to be included in the returned view
    
    返回:
    
    a view of the portion of this set whose elements are greater than or equal to fromElement
    
    抛出:
    
    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 uses natural ordering, or its comparator does not permit null elements
    
    IllegalArgumentException - if this set itself has a restricted range, and fromElement lies outside the bounds of the range
    
    从以下版本开始:
    
    1.6
  - subSet
```
public SortedSet<E> subSet(E fromElement,
                           E toElement)
```
    从接口复制的说明: NavigableSet
    
    Returns a view of the portion of this set whose elements range from fromElement, inclusive, to toElement, exclusive. (If fromElement and toElement are 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 IllegalArgumentException on an attempt to insert an element outside its range.
    Equivalent to subSet(fromElement, true, toElement, false).
    
    指定者:
    
    subSet 在接口中 NavigableSet<E>
    
    指定者:
    
    subSet 在接口中 SortedSet<E>
    
    参数:
    
    fromElement - low endpoint (inclusive) of the returned set
    
    toElement - high endpoint (exclusive) of the returned set
    
    返回:
    
    a view of the portion of this set whose elements range from fromElement, inclusive, to toElement, exclusive
    
    抛出:
    
    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 uses natural ordering, or its comparator 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
  - headSet
```
public SortedSet<E> headSet(E toElement)
```
    从接口复制的说明: NavigableSet
    
    Returns a view of the portion of this set whose elements are strictly less than 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.
    Equivalent to headSet(toElement, false).
    
    指定者:
    
    headSet 在接口中 NavigableSet<E>
    
    指定者:
    
    headSet 在接口中 SortedSet<E>
    
    参数:
    
    toElement - high endpoint (exclusive) of the returned set
    
    返回:
    
    a view of the portion of this set whose elements are strictly less than toElement
    
    抛出:
    
    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 uses natural ordering, or its comparator does not permit null elements
    
    IllegalArgumentException - if this set itself has a restricted range, and toElement lies outside the bounds of the range
  - tailSet
```
public SortedSet<E> tailSet(E fromElement)
```
    从接口复制的说明: NavigableSet
    
    Returns a view of the portion of this set whose elements are greater than or equal to 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.
    Equivalent to tailSet(fromElement, true).
    
    指定者:
    
    tailSet 在接口中 NavigableSet<E>
    
    指定者:
    
    tailSet 在接口中 SortedSet<E>
    
    参数:
    
    fromElement - low endpoint (inclusive) of the returned set
    
    返回:
    
    a view of the portion of this set whose elements are greater than or equal to fromElement
    
    抛出:
    
    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 uses natural ordering, or its comparator does not permit null elements
    
    IllegalArgumentException - if this set itself has a restricted range, and fromElement lies outside the bounds of the range
  - comparator
```
public Comparator<? super E> comparator()
```
    从接口复制的说明: SortedSet
    
    Returns the comparator used to order the elements in this set, or null if this set uses the Comparable of its elements.
    
    指定者:
    
    comparator 在接口中 SortedSet<E>
    
    返回:
    
    the comparator used to order the elements in this set, or null if this set uses the natural ordering of its elements
  - first
```
public E first()
```
    从接口复制的说明: SortedSet
    
    Returns the first (lowest) element currently in this set.
    
    指定者:
    
    first 在接口中 SortedSet<E>
    
    返回:
    
    the first (lowest) element currently in this set
    
    抛出:
    
    NoSuchElementException - if this set is empty
  - last
```
public E last()
```
    从接口复制的说明: SortedSet
    
    Returns the last (highest) element currently in this set.
    
    指定者:
    
    last 在接口中 SortedSet<E>
    
    返回:
    
    the last (highest) element currently in this set
    
    抛出:
    
    NoSuchElementException - if this set is empty
  - lower
```
public E lower(E e)
```
    从接口复制的说明: NavigableSet
    
    Returns the greatest element in this set strictly less than the given element, or null if there is no such element.
    
    指定者:
    
    lower 在接口中 NavigableSet<E>
    
    参数:
    
    e - the value to match
    
    返回:
    
    the greatest element less than e, or null if there is no such element
    
    抛出:
    
    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 uses natural ordering, or its comparator does not permit null elements
    
    从以下版本开始:
    
    1.6
  - floor
```
public E floor(E e)
```
    从接口复制的说明: NavigableSet
    
    Returns the greatest element in this set less than or equal to the given element, or null if there is no such element.
    
    指定者:
    
    floor 在接口中 NavigableSet<E>
    
    参数:
    
    e - the value to match
    
    返回:
    
    the greatest element less than or equal to e, or null if there is no such element
    
    抛出:
    
    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 uses natural ordering, or its comparator does not permit null elements
    
    从以下版本开始:
    
    1.6
  - ceiling
```
public E ceiling(E e)
```
    从接口复制的说明: NavigableSet
    
    Returns the least element in this set greater than or equal to the given element, or null if there is no such element.
    
    指定者:
    
    ceiling 在接口中 NavigableSet<E>
    
    参数:
    
    e - the value to match
    
    返回:
    
    the least element greater than or equal to e, or null if there is no such element
    
    抛出:
    
    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 uses natural ordering, or its comparator does not permit null elements
    
    从以下版本开始:
    
    1.6
  - higher
```
public E higher(E e)
```
    从接口复制的说明: NavigableSet
    
    Returns the least element in this set strictly greater than the given element, or null if there is no such element.
    
    指定者:
    
    higher 在接口中 NavigableSet<E>
    
    参数:
    
    e - the value to match
    
    返回:
    
    the least element greater than e, or null if there is no such element
    
    抛出:
    
    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 uses natural ordering, or its comparator does not permit null elements
    
    从以下版本开始:
    
    1.6
  - pollFirst
```
public E pollFirst()
```
    从接口复制的说明: NavigableSet
    
    Retrieves and removes the first (lowest) element, or returns null if this set is empty.
    
    指定者:
    
    pollFirst 在接口中 NavigableSet<E>
    
    返回:
    
    the first element, or null if this set is empty
    
    从以下版本开始:
    
    1.6
  - pollLast
```
public E pollLast()
```
    从接口复制的说明: NavigableSet
    
    Retrieves and removes the last (highest) element, or returns null if this set is empty.
    
    指定者:
    
    pollLast 在接口中 NavigableSet<E>
    
    返回:
    
    the last element, or null if this set is empty
    
    从以下版本开始:
    
    1.6
  - clone
```
public Object clone()
```
    Returns a shallow copy of this TreeSet instance. (The elements themselves are not cloned.)
    
    覆盖:
    
    clone 在类中 Object
    
    返回:
    
    a shallow copy of this set
    
    另请参阅:
    
    Cloneable
  - spliterator
```
public Spliterator<E> spliterator()
```
    Creates a late-binding and fail-fast Spliterator over the elements in this set.
    The Spliterator reports Spliterator#SIZED, Spliterator#DISTINCT, Spliterator#SORTED, and Spliterator#ORDERED. Overriding implementations should document the reporting of additional characteristic values.
    The spliterator's comparator (see Spliterator.getComparator()) is null if the tree set's comparator (see comparator()) is null. Otherwise, the spliterator's comparator is the same as or imposes the same total ordering as the tree set's comparator.
    
    指定者:
    
    spliterator 在接口中 Collection<E>
    
    指定者:
    
    spliterator 在接口中 Iterable<E>
    
    指定者:
    
    spliterator 在接口中 Set<E>
    
    指定者:
    
    spliterator 在接口中 SortedSet<E>
    
    返回:
    
    a Spliterator over the elements in this set
    
    从以下版本开始:
    
    1.8

类 TreeSet<E>

构造器概要

方法概要

从类继承的方法 java.util.AbstractCollection

从类继承的方法 java.util.AbstractSet

从接口继承的方法 java.util.Collection

从接口继承的方法 java.lang.Iterable

从类继承的方法 java.lang.Object

从接口继承的方法 java.util.Set

构造器详细资料

TreeSet

TreeSet

TreeSet

TreeSet

方法详细资料

iterator

descendingIterator

descendingSet

size

isEmpty

contains

add

remove

clear

addAll

subSet

headSet

tailSet

subSet

headSet

tailSet

comparator

first

last

lower

floor

ceiling

higher

pollFirst

pollLast

clone

spliterator