Module java.base

Class ConcurrentSkipListSet<E>

    • Constructor Detail

      • ConcurrentSkipListSet

        public ConcurrentSkipListSet​()
        Constructs a new, empty set that orders its elements according to their natural ordering.
      • ConcurrentSkipListSet

        public ConcurrentSkipListSet​(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​(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:
        ClassCastException - if the elements in c are not Comparable, or are not mutually comparable
        NullPointerException - if the specified collection or any of its elements are null
      • ConcurrentSkipListSet

        public ConcurrentSkipListSet​(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:
        NullPointerException - if the specified sorted set or any of its elements are null
    • Method Detail

      • clone

        public ConcurrentSkipListSet<E> clone​()
        Returns a shallow copy of this ConcurrentSkipListSet instance. (The elements themselves are not cloned.)
        Overrides:
        clone in class Object
        Returns:
        a shallow copy of this set
      • 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 Collection<E>
        Specified by:
        size in interface Set<E>
        Specified by:
        size in class 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 Collection<E>
        Specified by:
        isEmpty in interface Set<E>
        Overrides:
        isEmpty in class AbstractCollection<E>
        Returns:
        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.equals(e).
        Specified by:
        contains in interface Collection<E>
        Specified by:
        contains in interface Set<E>
        Overrides:
        contains in class AbstractCollection<E>
        Parameters:
        o - object to be checked for containment in this set
        Returns:
        true if this set contains the specified element
        Throws:
        ClassCastException - if the specified element cannot be compared with the elements currently in this set
        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 Collection<E>
        Specified by:
        add in interface Set<E>
        Overrides:
        add in class AbstractCollection<E>
        Parameters:
        e - element to be added to this set
        Returns:
        true if this set did not already contain the specified element
        Throws:
        ClassCastException - if e cannot be compared with the elements currently in this set
        NullPointerException - if the specified element is null
      • 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.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 Collection<E>
        Specified by:
        remove in interface Set<E>
        Overrides:
        remove in class AbstractCollection<E>
        Parameters:
        o - object to be removed from this set, if present
        Returns:
        true if this set contained the specified element
        Throws:
        ClassCastException - if o cannot be compared with the elements currently in this set
        NullPointerException - if the specified element is null
      • descendingIterator

        public Iterator<E> descendingIterator​()
        Returns an iterator over the elements in this set in descending order.
        Specified by:
        descendingIterator in interface NavigableSet<E>
        Returns:
        an iterator over the elements in this set in descending order
      • equals

        public boolean equals​(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 Collection<E>
        Specified by:
        equals in interface Set<E>
        Overrides:
        equals in class 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​(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 Collection<E>
        Specified by:
        removeAll in interface Set<E>
        Overrides:
        removeAll in class 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:
        ClassCastException - if the class of an element of this set is incompatible with the specified collection (optional)
        NullPointerException - if the specified collection or any of its elements are null
      • lower

        public E lower​(E e)
        Description copied from interface: NavigableSet
        Returns the greatest element in this set strictly less than the given element, or null if there is no such element.
        Specified by:
        lower in interface NavigableSet<E>
        Parameters:
        e - the value to match
        Returns:
        the greatest element less than e, or null if there is no such element
        Throws:
        ClassCastException - if the specified element cannot be compared with the elements currently in the set
        NullPointerException - if the specified element is null
      • floor

        public E floor​(E e)
        Description copied from interface: NavigableSet
        Returns the greatest element in this set less than or equal to the given element, or null if there is no such element.
        Specified by:
        floor in interface NavigableSet<E>
        Parameters:
        e - the value to match
        Returns:
        the greatest element less than or equal to e, or null if there is no such element
        Throws:
        ClassCastException - if the specified element cannot be compared with the elements currently in the set
        NullPointerException - if the specified element is null
      • ceiling

        public E ceiling​(E e)
        Description copied from interface: NavigableSet
        Returns the least element in this set greater than or equal to the given element, or null if there is no such element.
        Specified by:
        ceiling in interface NavigableSet<E>
        Parameters:
        e - the value to match
        Returns:
        the least element greater than or equal to e, or null if there is no such element
        Throws:
        ClassCastException - if the specified element cannot be compared with the elements currently in the set
        NullPointerException - if the specified element is null
      • higher

        public E higher​(E e)
        Description copied from interface: NavigableSet
        Returns the least element in this set strictly greater than the given element, or null if there is no such element.
        Specified by:
        higher in interface NavigableSet<E>
        Parameters:
        e - the value to match
        Returns:
        the least element greater than e, or null if there is no such element
        Throws:
        ClassCastException - if the specified element cannot be compared with the elements currently in the set
        NullPointerException - if the specified element is null
      • pollFirst

        public E pollFirst​()
        Description copied from interface: NavigableSet
        Retrieves and removes the first (lowest) element, or returns null if this set is empty.
        Specified by:
        pollFirst in interface NavigableSet<E>
        Returns:
        the first element, or null if this set is empty
      • pollLast

        public E pollLast​()
        Description copied from interface: NavigableSet
        Retrieves and removes the last (highest) element, or returns null if this set is empty.
        Specified by:
        pollLast in interface NavigableSet<E>
        Returns:
        the last element, or null if this set is empty
      • subSet

        public NavigableSet<E> subSet​(E fromElement,
                                      boolean fromInclusive,
                                      E toElement,
                                      boolean toInclusive)
        Description copied from interface: 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.

        Specified by:
        subSet in interface NavigableSet<E>
        Parameters:
        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
        Returns:
        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 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
        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 NavigableSet<E> headSet​(E toElement,
                                       boolean inclusive)
        Description copied from interface: 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.

        Specified by:
        headSet in interface NavigableSet<E>
        Parameters:
        toElement - high endpoint of the returned set
        inclusive - true if the high endpoint is to be included in the returned view
        Returns:
        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 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
        IllegalArgumentException - if this set itself has a restricted range, and toElement lies outside the bounds of the range
      • tailSet

        public NavigableSet<E> tailSet​(E fromElement,
                                       boolean inclusive)
        Description copied from interface: 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.

        Specified by:
        tailSet in interface NavigableSet<E>
        Parameters:
        fromElement - low endpoint of the returned set
        inclusive - true if the low endpoint is to be included in the returned view
        Returns:
        a view of the portion of this set whose elements are greater than or equal to fromElement
        Throws:
        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
        IllegalArgumentException - if this set itself has a restricted range, and fromElement lies outside the bounds of the range
      • descendingSet

        public 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 NavigableSet<E>
        Returns:
        a reverse order view of this set