ConcurrentSkipListSet (quasar-core 0.7.10 API)

java.lang.Object
- java.util.AbstractCollection<E>
- - java.util.AbstractSet<E>
  - - co.paralleluniverse.concurrent.util.ConcurrentSkipListSet<E>

Type Parameters:

E - the type of elements maintained by this set

All Implemented Interfaces:

java.io.Serializable, java.lang.Iterable<E>, java.util.Collection<E>, java.util.NavigableSet<E>, java.util.Set<E>, java.util.SortedSet<E>
```
public class ConcurrentSkipListSet<E>
extends java.util.AbstractSet<E>
implements java.util.NavigableSet<E>, java.io.Serializable
```
A scalable concurrent NavigableSet implementation based on a ConcurrentSkipListMap. The elements of the set are kept sorted according to their natural ordering, or by a Comparator provided at set creation time, depending on which constructor is used.
This implementation provides expected average log(n) time cost for the contains, add, and remove operations and their variants. Insertion, removal, and access operations safely execute concurrently by multiple threads. Iterators are weakly consistent, returning elements reflecting the state of the set at some point at or since the creation of the iterator. They do not throw ConcurrentModificationException, and may proceed concurrently with other operations. Ascending ordered views and their iterators are faster than descending ones.
Beware that, unlike in most collections, the size method is not a constant-time operation. Because of the asynchronous nature of these sets, determining the current number of elements requires a traversal of the elements, and so may report inaccurate results if this collection is modified during traversal. Additionally, the bulk operations addAll, removeAll, retainAll, containsAll, equals, and toArray are not guaranteed to be performed atomically. For example, an iterator operating concurrently with an addAll operation might view only some of the added elements.
This class and its iterators implement all of the optional methods of the Set and Iterator interfaces. Like most other concurrent collection implementations, this class does not permit the use of null elements, because null arguments and return values cannot be reliably distinguished from the absence of elements.
This class is a member of the Java Collections Framework.

Since:

1.6

See Also:

Serialized Form

Constructor Summary

Constructors
Constructor and Description
`ConcurrentSkipListSet()` Constructs a new, empty set that orders its elements according to their natural ordering.
`ConcurrentSkipListSet(java.util.Collection<? extends E> c)` Constructs a new set containing the elements in the specified collection, that orders its elements according to their natural ordering.
`ConcurrentSkipListSet(java.util.Comparator<? super E> comparator)` Constructs a new, empty set that orders its elements according to the specified comparator.
`ConcurrentSkipListSet(java.util.SortedSet<E> s)` Constructs a new set containing the same elements and using the same ordering as the specified sorted set.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`boolean`	`add(E e)` Adds the specified element to this set if it is not already present.
`E`	`ceiling(E e)`
`void`	`clear()` Removes all of the elements from this set.
`java.util.Comparator<? super E>`	`comparator()`
`boolean`	`contains(java.lang.Object o)` Returns `true` if this set contains the specified element.
`java.util.Iterator<E>`	`descendingIterator()` Returns an iterator over the elements in this set in descending order.
`java.util.NavigableSet<E>`	`descendingSet()` Returns a reverse order view of the elements contained in this set.
`boolean`	`equals(java.lang.Object o)` Compares the specified object with this set for equality.
`E`	`first()`
`E`	`floor(E e)`
`java.util.NavigableSet<E>`	`headSet(E toElement)`
`java.util.NavigableSet<E>`	`headSet(E toElement, boolean inclusive)`
`E`	`higher(E e)`
`boolean`	`isEmpty()` Returns `true` if this set contains no elements.
`java.util.Iterator<E>`	`iterator()` Returns an iterator over the elements in this set in ascending order.
`E`	`last()`
`E`	`lower(E e)`
`E`	`peekFirst()`
`E`	`peekLast()`
`E`	`pollFirst()`
`E`	`pollLast()`
`boolean`	`remove(java.lang.Object o)` Removes the specified element from this set if it is present.
`boolean`	`removeAll(java.util.Collection<?> c)` Removes from this set all of its elements that are contained in the specified collection.
`int`	`size()` Returns the number of elements in this set.
`java.util.NavigableSet<E>`	`subSet(E fromElement, boolean fromInclusive, E toElement, boolean toInclusive)`
`java.util.NavigableSet<E>`	`subSet(E fromElement, E toElement)`
`java.util.NavigableSet<E>`	`tailSet(E fromElement)`
`java.util.NavigableSet<E>`	`tailSet(E fromElement, boolean inclusive)`

Methods inherited from class java.util.AbstractSet
hashCode

Methods inherited from class java.util.AbstractCollection
addAll, containsAll, retainAll, toArray, toArray, toString

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.SortedSet
spliterator

Methods inherited from interface java.util.Set
addAll, containsAll, hashCode, retainAll, toArray, toArray

Methods inherited from interface java.util.Collection
parallelStream, removeIf, stream

Methods inherited from interface java.lang.Iterable
forEach

- Constructor Detail
  - ConcurrentSkipListSet
```
public ConcurrentSkipListSet()
```
    Constructs a new, empty set that orders its elements according to their natural ordering.
  - ConcurrentSkipListSet
```
public ConcurrentSkipListSet(java.util.Comparator<? super E> comparator)
```
    Constructs a new, empty set that orders its elements according to the specified comparator.
    
    Parameters:
    
    comparator - the comparator that will be used to order this set. If null, the natural ordering of the elements will be used.
  - ConcurrentSkipListSet
```
public ConcurrentSkipListSet(java.util.Collection<? extends E> c)
```
    Constructs a new set containing the elements in the specified collection, that orders its elements according to their natural ordering.
    
    Parameters:
    
    c - The elements that will comprise the new set
    
    Throws:
    
    java.lang.ClassCastException - if the elements in c are not Comparable, or are not mutually comparable
    
    java.lang.NullPointerException - if the specified collection or any of its elements are null
  - ConcurrentSkipListSet
```
public ConcurrentSkipListSet(java.util.SortedSet<E> s)
```
    Constructs a new set containing the same elements and using the same ordering as the specified sorted set.
    
    Parameters:
    
    s - sorted set whose elements will comprise the new set
    
    Throws:
    
    java.lang.NullPointerException - if the specified sorted set or any of its elements are null
- Method Detail
  - size
```
public int size()
```
    Returns the number of elements in this set. If this set contains more than Integer.MAX_VALUE elements, it returns Integer.MAX_VALUE.
    Beware that, unlike in most collections, this method is NOT a constant-time operation. Because of the asynchronous nature of these sets, determining the current number of elements requires traversing them all to count them. Additionally, it is possible for the size to change during execution of this method, in which case the returned result will be inaccurate. Thus, this method is typically not very useful in concurrent applications.
    
    Specified by:
    
    size in interface java.util.Collection<E>
    
    Specified by:
    
    size in interface java.util.Set<E>
    
    Specified by:
    
    size in class java.util.AbstractCollection<E>
    
    Returns:
    
    the number of elements in this set
  - isEmpty
```
public boolean isEmpty()
```
    Returns true if this set contains no elements.
    
    Specified by:
    
    isEmpty in interface java.util.Collection<E>
    
    Specified by:
    
    isEmpty in interface java.util.Set<E>
    
    Overrides:
    
    isEmpty in class java.util.AbstractCollection<E>
    
    Returns:
    
    true if this set contains no elements
  - contains
```
public boolean contains(java.lang.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.equals(e).
    
    Specified by:
    
    contains in interface java.util.Collection<E>
    
    Specified by:
    
    contains in interface java.util.Set<E>
    
    Overrides:
    
    contains in class java.util.AbstractCollection<E>
    
    Parameters:
    
    o - object to be checked for containment in this set
    
    Returns:
    
    true if this set contains the specified element
    
    Throws:
    
    java.lang.ClassCastException - if the specified element cannot be compared with the elements currently in this set
    
    java.lang.NullPointerException - if the specified element is null
  - 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.equals(e2). If this set already contains the element, the call leaves the set unchanged and returns false.
    
    Specified by:
    
    add in interface java.util.Collection<E>
    
    Specified by:
    
    add in interface java.util.Set<E>
    
    Overrides:
    
    add in class java.util.AbstractCollection<E>
    
    Parameters:
    
    e - element to be added to this set
    
    Returns:
    
    true if this set did not already contain the specified element
    
    Throws:
    
    java.lang.ClassCastException - if e cannot be compared with the elements currently in this set
    
    java.lang.NullPointerException - if the specified element is null
  - remove
```
public boolean remove(java.lang.Object o)
```
    Removes the specified element from this set if it is present. More formally, removes an element e such that 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.)
    
    Specified by:
    
    remove in interface java.util.Collection<E>
    
    Specified by:
    
    remove in interface java.util.Set<E>
    
    Overrides:
    
    remove in class java.util.AbstractCollection<E>
    
    Parameters:
    
    o - object to be removed from this set, if present
    
    Returns:
    
    true if this set contained the specified element
    
    Throws:
    
    java.lang.ClassCastException - if o cannot be compared with the elements currently in this set
    
    java.lang.NullPointerException - if the specified element is null
  - clear
```
public void clear()
```
    Removes all of the elements from this set.
    
    Specified by:
    
    clear in interface java.util.Collection<E>
    
    Specified by:
    
    clear in interface java.util.Set<E>
    
    Overrides:
    
    clear in class java.util.AbstractCollection<E>
  - iterator
```
public java.util.Iterator<E> iterator()
```
    Returns an iterator over the elements in this set in ascending order.
    
    Specified by:
    
    iterator in interface java.lang.Iterable<E>
    
    Specified by:
    
    iterator in interface java.util.Collection<E>
    
    Specified by:
    
    iterator in interface java.util.NavigableSet<E>
    
    Specified by:
    
    iterator in interface java.util.Set<E>
    
    Specified by:
    
    iterator in class java.util.AbstractCollection<E>
    
    Returns:
    
    an iterator over the elements in this set in ascending order
  - descendingIterator
```
public java.util.Iterator<E> descendingIterator()
```
    Returns an iterator over the elements in this set in descending order.
    
    Specified by:
    
    descendingIterator in interface java.util.NavigableSet<E>
    
    Returns:
    
    an iterator over the elements in this set in descending order
  - equals
```
public boolean equals(java.lang.Object o)
```
    Compares the specified object with this set for equality. Returns true if the specified object is also a set, the two sets have the same size, and every member of the specified set is contained in this set (or equivalently, every member of this set is contained in the specified set). This definition ensures that the equals method works properly across different implementations of the set interface.
    
    Specified by:
    
    equals in interface java.util.Collection<E>
    
    Specified by:
    
    equals in interface java.util.Set<E>
    
    Overrides:
    
    equals in class java.util.AbstractSet<E>
    
    Parameters:
    
    o - the object to be compared for equality with this set
    
    Returns:
    
    true if the specified object is equal to this set
  - removeAll
```
public boolean removeAll(java.util.Collection<?> c)
```
    Removes from this set all of its elements that are contained in the specified collection. If the specified collection is also a set, this operation effectively modifies this set so that its value is the asymmetric set difference of the two sets.
    
    Specified by:
    
    removeAll in interface java.util.Collection<E>
    
    Specified by:
    
    removeAll in interface java.util.Set<E>
    
    Overrides:
    
    removeAll in class java.util.AbstractSet<E>
    
    Parameters:
    
    c - collection containing elements to be removed from this set
    
    Returns:
    
    true if this set changed as a result of the call
    
    Throws:
    
    java.lang.ClassCastException - if the types of one or more elements in this set are incompatible with the specified collection
    
    java.lang.NullPointerException - if the specified collection or any of its elements are null
  - lower
```
public E lower(E e)
```
    Specified by:
    
    lower in interface java.util.NavigableSet<E>
    
    Throws:
    
    java.lang.ClassCastException
    
    java.lang.NullPointerException - if the specified element is null
  - floor
```
public E floor(E e)
```
    Specified by:
    
    floor in interface java.util.NavigableSet<E>
    
    Throws:
    
    java.lang.ClassCastException
    
    java.lang.NullPointerException - if the specified element is null
  - ceiling
```
public E ceiling(E e)
```
    Specified by:
    
    ceiling in interface java.util.NavigableSet<E>
    
    Throws:
    
    java.lang.ClassCastException
    
    java.lang.NullPointerException - if the specified element is null
  - higher
```
public E higher(E e)
```
    Specified by:
    
    higher in interface java.util.NavigableSet<E>
    
    Throws:
    
    java.lang.ClassCastException
    
    java.lang.NullPointerException - if the specified element is null
  - pollFirst
```
public E pollFirst()
```
    Specified by:
    
    pollFirst in interface java.util.NavigableSet<E>
  - pollLast
```
public E pollLast()
```
    Specified by:
    
    pollLast in interface java.util.NavigableSet<E>
  - comparator
```
public java.util.Comparator<? super E> comparator()
```
    Specified by:
    
    comparator in interface java.util.SortedSet<E>
  - first
```
public E first()
```
    Specified by:
    
    first in interface java.util.SortedSet<E>
    
    Throws:
    
    java.util.NoSuchElementException
  - peekFirst
```
public E peekFirst()
```
  - last
```
public E last()
```
    Specified by:
    
    last in interface java.util.SortedSet<E>
    
    Throws:
    
    java.util.NoSuchElementException
  - peekLast
```
public E peekLast()
```
  - subSet
```
public java.util.NavigableSet<E> subSet(E fromElement,
                                        boolean fromInclusive,
                                        E toElement,
                                        boolean toInclusive)
```
    Specified by:
    
    subSet in interface java.util.NavigableSet<E>
    
    Throws:
    
    java.lang.ClassCastException
    
    java.lang.NullPointerException - if fromElement or toElement is null
    
    java.lang.IllegalArgumentException
  - headSet
```
public java.util.NavigableSet<E> headSet(E toElement,
                                         boolean inclusive)
```
    Specified by:
    
    headSet in interface java.util.NavigableSet<E>
    
    Throws:
    
    java.lang.ClassCastException
    
    java.lang.NullPointerException - if toElement is null
    
    java.lang.IllegalArgumentException
  - tailSet
```
public java.util.NavigableSet<E> tailSet(E fromElement,
                                         boolean inclusive)
```
    Specified by:
    
    tailSet in interface java.util.NavigableSet<E>
    
    Throws:
    
    java.lang.ClassCastException
    
    java.lang.NullPointerException - if fromElement is null
    
    java.lang.IllegalArgumentException
  - subSet
```
public java.util.NavigableSet<E> subSet(E fromElement,
                                        E toElement)
```
    Specified by:
    
    subSet in interface java.util.NavigableSet<E>
    
    Specified by:
    
    subSet in interface java.util.SortedSet<E>
    
    Throws:
    
    java.lang.ClassCastException
    
    java.lang.NullPointerException - if fromElement or toElement is null
    
    java.lang.IllegalArgumentException
  - headSet
```
public java.util.NavigableSet<E> headSet(E toElement)
```
    Specified by:
    
    headSet in interface java.util.NavigableSet<E>
    
    Specified by:
    
    headSet in interface java.util.SortedSet<E>
    
    Throws:
    
    java.lang.ClassCastException
    
    java.lang.NullPointerException - if toElement is null
    
    java.lang.IllegalArgumentException
  - tailSet
```
public java.util.NavigableSet<E> tailSet(E fromElement)
```
    Specified by:
    
    tailSet in interface java.util.NavigableSet<E>
    
    Specified by:
    
    tailSet in interface java.util.SortedSet<E>
    
    Throws:
    
    java.lang.ClassCastException
    
    java.lang.NullPointerException - if fromElement is null
    
    java.lang.IllegalArgumentException
  - descendingSet
```
public java.util.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.
    The returned set has an ordering equivalent to Collections.reverseOrder(comparator()). The expression s.descendingSet().descendingSet() returns a view of s essentially equivalent to s.
    
    Specified by:
    
    descendingSet in interface java.util.NavigableSet<E>
    
    Returns:
    
    a reverse order view of this set

Class ConcurrentSkipListSet<E>

Constructor Summary

Method Summary

Methods inherited from class java.util.AbstractSet

Methods inherited from class java.util.AbstractCollection

Methods inherited from class java.lang.Object

Methods inherited from interface java.util.SortedSet

Methods inherited from interface java.util.Set

Methods inherited from interface java.util.Collection

Methods inherited from interface java.lang.Iterable

Constructor Detail

ConcurrentSkipListSet

ConcurrentSkipListSet

ConcurrentSkipListSet

ConcurrentSkipListSet

Method Detail

size

isEmpty

contains

add

remove

clear

iterator

descendingIterator

equals

removeAll

lower

floor

ceiling

higher

pollFirst

pollLast

comparator

first

peekFirst

last

peekLast

subSet

headSet

tailSet

subSet

headSet

tailSet

descendingSet