TreeSet class « TreeSet « Set « Collections

Create TreeSet objects

Constructor	Summary
TreeSet()	Creates a new, empty tree set, sorted according to the natural ordering of its elements.
TreeSet(Collection<? extends E> c)	Creates 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)	Creates a new, empty tree set, sorted according to the specified comparator.
TreeSet(SortedSet<E> s)	Creates a new tree set containing the same elements and using the same ordering as the specified sorted set.

Add elements to a TreeSet

Return	Method	Summary
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.

Get the least and greatest element in this TreeSet

Return	Method	Summary
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.
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.
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.
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.

Clear a TreeSet

Return	Method	Summary
void	clear()	Removes all of the elements from this set.

Clone a TreeSet

Return	Method	Summary
Object	clone()	Returns a shallow copy of this TreeSet instance.

Get the comparator used by this TreeSet

Return	Method	Summary
Comparator<? super E>	comparator()	Returns the comparator used to order the elements in this set, or null if this set uses the natural ordering of its elements.

If this TreeSet contains a certain element

Return	Method	Summary
boolean	contains(Object o)	Returns true if this set contains the specified element.

Get the descending iterator and descending set

Return	Method	Summary
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.

The first and last element in this TreeSet

Return	Method	Summary
E	first()	Returns the first (lowest) element currently in this set.
E	last()	Returns the last (highest) element currently in this set.

Get the head set and tail set

Return	Method	Summary
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.
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.

Is this TreeSet empty

Return	Method	Summary
boolean	isEmpty()	Returns true if this set contains no elements.

Get an iterator over the elements in this set in ascending order

Return	Method	Summary
Iterator<E>	iterator()	Returns an iterator over the elements in this set in ascending order.

Get and remove first and last element in this tree

Return	Method	Summary
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.

Remove element from TreeSet

Return	Method	Summary
boolean	remove(Object o)	Removes the specified element from this set if it is present.

Get the size of this TreeSet

Return	Method	Summary
int	size()	Returns the number of elements in this set (its cardinality).

Get a subset from this TreeSet

Return	Method	Summary
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.