Package com.macrofocus.utils

Class IndexedTreeSet<E>

java.lang.Object
java.util.AbstractCollection<E>
java.util.AbstractSet<E>
com.macrofocus.utils.IndexedTreeSet<E>
Type Parameters:
E - the type of elements maintained by this set
All Implemented Interfaces:
IndexedNavigableSet<E>, Serializable, Cloneable, Iterable<E>, Collection<E>, NavigableSet<E>, SequencedCollection<E>, SequencedSet<E>, Set<E>, SortedSet<E>
public class IndexedTreeSet<E> extends AbstractSet<E> implements IndexedNavigableSet<E>, Cloneable, Serializable
A NavigableSet implementation based on a IndexedTreeMap. The elements are ordered using their natural ordering, 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 IndexedTreeSet 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 IndexedTreeSet(...));

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.

Since:
1.2
See Also:

  • Constructor Details

    • IndexedTreeSet

      public IndexedTreeSet()
      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.

    • IndexedTreeSet

      public IndexedTreeSet(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.
      Parameters:
      comparator - the comparator that will be used to order this set. If null, the natural ordering of the elements will be used.

    • IndexedTreeSet

      public IndexedTreeSet(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.
      Parameters:
      c - collection whose elements 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 is null

    • IndexedTreeSet

      public IndexedTreeSet(SortedSet<E> s)
      Constructs a new tree 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 is null

  • Method Details

    • iterator

      public Iterator<E> iterator()
      Returns an iterator over the elements in this set in ascending order.
      Specified by:
      iterator in interface Collection<E>
      Specified by:
      iterator in interface Iterable<E>
      Specified by:
      iterator in interface NavigableSet<E>
      Specified by:
      iterator in interface Set<E>
      Specified by:
      iterator in class AbstractCollection<E>
      Returns:
      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.
      Specified by:
      descendingIterator in interface NavigableSet<E>
      Returns:
      an iterator over the elements in this set in descending order
      Since:
      1.6

    • descendingSet

      public NavigableSet<E> descendingSet()
      Specified by:
      descendingSet in interface NavigableSet<E>
      Since:
      1.6

    • size

      public int size()
      Returns the number of elements in this set (its cardinality).
      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 (its cardinality)

    • 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==null ? e==null : 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 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.
      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 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.)
      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 con tained the specified element
      Throws:
      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.
      Specified by:
      clear in interface Collection<E>
      Specified by:
      clear in interface Set<E>
      Overrides:
      clear in class AbstractCollection<E>

    • addAll

      public boolean addAll(Collection<? extends E> c)
      Adds all of the elements in the specified collection to this set.
      Specified by:
      addAll in interface Collection<E>
      Specified by:
      addAll in interface Set<E>
      Overrides:
      addAll in class AbstractCollection<E>
      Parameters:
      c - collection containing elements to be added to this set
      Returns:
      true if this set changed as a result of the call
      Throws:
      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

    • subSet

      public NavigableSet<E> subSet(E fromElement, boolean fromInclusive, E toElement, boolean toInclusive)
      Specified by:
      subSet in interface NavigableSet<E>
      Since:
      1.6

    • headSet

      public NavigableSet<E> headSet(E toElement, boolean inclusive)
      Specified by:
      headSet in interface NavigableSet<E>
      Since:
      1.6

    • tailSet

      public NavigableSet<E> tailSet(E fromElement, boolean inclusive)
      Specified by:
      tailSet in interface NavigableSet<E>
      Since:
      1.6

    • subSet

      public SortedSet<E> subSet(E fromElement, E toElement)
      Specified by:
      subSet in interface NavigableSet<E>
      Specified by:
      subSet in interface SortedSet<E>

    • headSet

      public SortedSet<E> headSet(E toElement)
      Specified by:
      headSet in interface NavigableSet<E>
      Specified by:
      headSet in interface SortedSet<E>

    • tailSet

      public SortedSet<E> tailSet(E fromElement)
      Specified by:
      tailSet in interface NavigableSet<E>
      Specified by:
      tailSet in interface SortedSet<E>

    • comparator

      public Comparator<? super E> comparator()
      Specified by:
      comparator in interface SortedSet<E>

    • first

      public E first()
      Specified by:
      first in interface SortedSet<E>

    • last

      public E last()
      Specified by:
      last in interface SortedSet<E>

    • lower

      public E lower(E e)
      Specified by:
      lower in interface NavigableSet<E>
      Since:
      1.6

    • floor

      public E floor(E e)
      Specified by:
      floor in interface NavigableSet<E>
      Since:
      1.6

    • ceiling

      public E ceiling(E e)
      Specified by:
      ceiling in interface NavigableSet<E>
      Since:
      1.6

    • higher

      public E higher(E e)
      Specified by:
      higher in interface NavigableSet<E>
      Since:
      1.6

    • pollFirst

      public E pollFirst()
      Specified by:
      pollFirst in interface NavigableSet<E>
      Since:
      1.6

    • pollLast

      public E pollLast()
      Specified by:
      pollLast in interface NavigableSet<E>
      Since:
      1.6

    • exact

      public E exact(int index)
      Description copied from interface: IndexedNavigableSet
      Returns the entry located at the index offset from the beginning of the sorted set
      Specified by:
      exact in interface IndexedNavigableSet<E>
      Parameters:
      index - index of the entry
      Returns:
      the entry located at the index (@code index) offset from the beginning of the sorted set

    • entryIndex

      public int entryIndex(E e)
      Description copied from interface: IndexedNavigableSet
      Searches the specified tree map for the specified entry using the put algorithm. Calculates its offset from the beginning of the sorted map using weights.
      Specified by:
      entryIndex in interface IndexedNavigableSet<E>
      Parameters:
      e - the entry
      Returns:
      index of the searched entry, if it is contained in the tree map; otherwise a NullPointerException is thrown

    • debug

      public void debug() throws Exception
      Throws:
      Exception