java.util
Class TreeSet<E>

java.lang.Object sample code for java.lang.Object definition code for java.lang.Object 
  extended by java.util.AbstractCollection sample code for java.util.AbstractCollection definition code for java.util.AbstractCollection <E>
      extended by java.util.AbstractSet sample code for java.util.AbstractSet definition code for java.util.AbstractSet <E>
          extended by java.util.TreeSet<E>
All Implemented Interfaces:
Serializable sample code for java.io.Serializable definition code for java.io.Serializable , Cloneable sample code for java.lang.Cloneable definition code for java.lang.Cloneable , Iterable sample code for java.lang.Iterable definition code for java.lang.Iterable <E>, Collection sample code for java.util.Collection definition code for java.util.Collection <E>, Set sample code for java.util.Set definition code for java.util.Set <E>, SortedSet sample code for java.util.SortedSet definition code for java.util.SortedSet <E>

public class TreeSet<E>
extends AbstractSet sample code for java.util.AbstractSet definition code for java.util.AbstractSet <E>
implements SortedSet sample code for java.util.SortedSet definition code for java.util.SortedSet <E>, Cloneable sample code for java.lang.Cloneable definition code for java.lang.Cloneable , Serializable sample code for java.io.Serializable definition code for java.io.Serializable

This class implements the Set interface, backed by a TreeMap instance. This class guarantees that the sorted set will be in ascending element order, sorted according to the natural order of the elements (see Comparable), or by the 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 key comparisons using its compareTo (or compare) method, so two keys 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 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.synchronizedSet 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.

Since:
1.2
See Also:
Collection sample code for java.util.Collection definition code for java.util.Collection , Set sample code for java.util.Set definition code for java.util.Set , HashSet sample code for java.util.HashSet definition code for java.util.HashSet , Comparable sample code for java.lang.Comparable definition code for java.lang.Comparable , Comparator sample code for java.util.Comparator definition code for java.util.Comparator , Collections.synchronizedSortedSet(SortedSet) sample code for java.util.Collections.synchronizedSortedSet(java.util.SortedSet) definition code for java.util.Collections.synchronizedSortedSet(java.util.SortedSet) , TreeMap sample code for java.util.TreeMap definition code for java.util.TreeMap , Serialized Form

Constructor Summary
TreeSet sample code for java.util.TreeSet.TreeSet() definition code for java.util.TreeSet.TreeSet() ()
          Constructs a new, empty set, sorted according to the elements' natural order.
TreeSet sample code for java.util.TreeSet.TreeSet(java.util.Collection) definition code for java.util.TreeSet.TreeSet(java.util.Collection) (Collection sample code for java.util.Collection definition code for java.util.Collection <? extends E> c)
          Constructs a new set containing the elements in the specified collection, sorted according to the elements' natural order.
TreeSet sample code for java.util.TreeSet.TreeSet(java.util.Comparator) definition code for java.util.TreeSet.TreeSet(java.util.Comparator) (Comparator sample code for java.util.Comparator definition code for java.util.Comparator <? super E> c)
          Constructs a new, empty set, sorted according to the specified comparator.
TreeSet sample code for java.util.TreeSet.TreeSet(java.util.SortedSet) definition code for java.util.TreeSet.TreeSet(java.util.SortedSet) (SortedSet sample code for java.util.SortedSet definition code for java.util.SortedSet <E> s)
          Constructs a new set containing the same elements as the specified sorted set, sorted according to the same ordering.
 
Method Summary
 boolean add sample code for java.util.TreeSet.add(E) definition code for java.util.TreeSet.add(E) (E o)
          Adds the specified element to this set if it is not already present.
 boolean addAll sample code for java.util.TreeSet.addAll(java.util.Collection) definition code for java.util.TreeSet.addAll(java.util.Collection) (Collection sample code for java.util.Collection definition code for java.util.Collection <? extends E> c)
          Adds all of the elements in the specified collection to this set.
 void clear sample code for java.util.TreeSet.clear() definition code for java.util.TreeSet.clear() ()
          Removes all of the elements from this set.
 Object sample code for java.lang.Object definition code for java.lang.Object clone sample code for java.util.TreeSet.clone() definition code for java.util.TreeSet.clone() ()
          Returns a shallow copy of this TreeSet instance.
 Comparator sample code for java.util.Comparator definition code for java.util.Comparator <? super E> comparator sample code for java.util.TreeSet.comparator() definition code for java.util.TreeSet.comparator() ()
          Returns the comparator used to order this sorted set, or null if this tree set uses its elements natural ordering.
 boolean contains sample code for java.util.TreeSet.contains(java.lang.Object) definition code for java.util.TreeSet.contains(java.lang.Object) (Object sample code for java.lang.Object definition code for java.lang.Object  o)
          Returns true if this set contains the specified element.
 E first sample code for java.util.TreeSet.first() definition code for java.util.TreeSet.first() ()
          Returns the first (lowest) element currently in this sorted set.
 SortedSet sample code for java.util.SortedSet definition code for java.util.SortedSet <E> headSet sample code for java.util.TreeSet.headSet(E) definition code for java.util.TreeSet.headSet(E) (E toElement)
          Returns a view of the portion of this set whose elements are strictly less than toElement.
 boolean isEmpty sample code for java.util.TreeSet.isEmpty() definition code for java.util.TreeSet.isEmpty() ()
          Returns true if this set contains no elements.
 Iterator sample code for java.util.Iterator definition code for java.util.Iterator <E> iterator sample code for java.util.TreeSet.iterator() definition code for java.util.TreeSet.iterator() ()
          Returns an iterator over the elements in this set.
 E last sample code for java.util.TreeSet.last() definition code for java.util.TreeSet.last() ()
          Returns the last (highest) element currently in this sorted set.
 boolean remove sample code for java.util.TreeSet.remove(java.lang.Object) definition code for java.util.TreeSet.remove(java.lang.Object) (Object sample code for java.lang.Object definition code for java.lang.Object  o)
          Removes the specified element from this set if it is present.
 int size sample code for java.util.TreeSet.size() definition code for java.util.TreeSet.size() ()
          Returns the number of elements in this set (its cardinality).
 SortedSet sample code for java.util.SortedSet definition code for java.util.SortedSet <E> subSet sample code for java.util.TreeSet.subSet(E, E) definition code for java.util.TreeSet.subSet(E, E) (E fromElement, E toElement)
          Returns a view of the portion of this set whose elements range from fromElement, inclusive, to toElement, exclusive.
 SortedSet sample code for java.util.SortedSet definition code for java.util.SortedSet <E> tailSet sample code for java.util.TreeSet.tailSet(E) definition code for java.util.TreeSet.tailSet(E) (E fromElement)
          Returns a view of the portion of this set whose elements are greater than or equal to fromElement.
 
Methods inherited from class java.util.AbstractSet sample code for java.util.AbstractSet definition code for java.util.AbstractSet
equals sample code for java.util.AbstractSet.equals(java.lang.Object) definition code for java.util.AbstractSet.equals(java.lang.Object) , hashCode sample code for java.util.AbstractSet.hashCode() definition code for java.util.AbstractSet.hashCode() , removeAll sample code for java.util.AbstractSet.removeAll(java.util.Collection) definition code for java.util.AbstractSet.removeAll(java.util.Collection)
 
Methods inherited from class java.util.AbstractCollection sample code for java.util.AbstractCollection definition code for java.util.AbstractCollection
containsAll sample code for java.util.AbstractCollection.containsAll(java.util.Collection) definition code for java.util.AbstractCollection.containsAll(java.util.Collection) , retainAll sample code for java.util.AbstractCollection.retainAll(java.util.Collection) definition code for java.util.AbstractCollection.retainAll(java.util.Collection) , toArray sample code for java.util.AbstractCollection.toArray() definition code for java.util.AbstractCollection.toArray() , toArray sample code for java.util.AbstractCollection.toArray(T[]) definition code for java.util.AbstractCollection.toArray(T[]) , toString sample code for java.util.AbstractCollection.toString() definition code for java.util.AbstractCollection.toString()
 
Methods inherited from class java.lang.Object sample code for java.lang.Object definition code for java.lang.Object
finalize sample code for java.lang.Object.finalize() definition code for java.lang.Object.finalize() , getClass sample code for java.lang.Object.getClass() definition code for java.lang.Object.getClass() , notify sample code for java.lang.Object.notify() definition code for java.lang.Object.notify() , notifyAll sample code for java.lang.Object.notifyAll() definition code for java.lang.Object.notifyAll() , wait sample code for java.lang.Object.wait() definition code for java.lang.Object.wait() , wait sample code for java.lang.Object.wait(long) definition code for java.lang.Object.wait(long) , wait sample code for java.lang.Object.wait(long, int) definition code for java.lang.Object.wait(long, int)
 
Methods inherited from interface java.util.Set sample code for java.util.Set definition code for java.util.Set
containsAll sample code for java.util.Set.containsAll(java.util.Collection) definition code for java.util.Set.containsAll(java.util.Collection) , equals sample code for java.util.Set.equals(java.lang.Object) definition code for java.util.Set.equals(java.lang.Object) , hashCode sample code for java.util.Set.hashCode() definition code for java.util.Set.hashCode() , removeAll sample code for java.util.Set.removeAll(java.util.Collection) definition code for java.util.Set.removeAll(java.util.Collection) , retainAll sample code for java.util.Set.retainAll(java.util.Collection) definition code for java.util.Set.retainAll(java.util.Collection) , toArray sample code for java.util.Set.toArray() definition code for java.util.Set.toArray() , toArray sample code for java.util.Set.toArray(T[]) definition code for java.util.Set.toArray(T[])
 

Constructor Detail

TreeSet sample code for java.util.TreeSet() definition code for java.util.TreeSet()

public TreeSet()
Constructs a new, empty set, sorted according to the elements' natural order. 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(Object) call will throw a ClassCastException.

See Also:
Comparable sample code for java.lang.Comparable definition code for java.lang.Comparable

TreeSet sample code for java.util.TreeSet(java.util.Comparator<? super E>) definition code for java.util.TreeSet(java.util.Comparator<? super E>)

public TreeSet(Comparator sample code for java.util.Comparator definition code for java.util.Comparator <? super E> c)
Constructs a new, empty 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(Object) call will throw a ClassCastException.

Parameters:
c - the comparator that will be used to sort this set. A null value indicates that the elements' natural ordering should be used.

TreeSet sample code for java.util.TreeSet(java.util.Collection<? extends E>) definition code for java.util.TreeSet(java.util.Collection<? extends E>)

public TreeSet(Collection sample code for java.util.Collection definition code for java.util.Collection <? extends E> c)
Constructs a new set containing the elements in the specified collection, sorted according to the elements' natural order. All keys inserted into the set must implement the Comparable interface. Furthermore, all such keys must be mutually comparable: k1.compareTo(k2) must not throw a ClassCastException for any elements k1 and k2 in the set.

Parameters:
c - The elements that will comprise the new set.
Throws:
ClassCastException sample code for java.lang.ClassCastException definition code for java.lang.ClassCastException - if the keys in the specified collection are not comparable, or are not mutually comparable.
NullPointerException sample code for java.lang.NullPointerException definition code for java.lang.NullPointerException - if the specified collection is null.

TreeSet sample code for java.util.TreeSet(java.util.SortedSet<E>) definition code for java.util.TreeSet(java.util.SortedSet<E>)

public TreeSet(SortedSet sample code for java.util.SortedSet definition code for java.util.SortedSet <E> s)
Constructs a new set containing the same elements as the specified sorted set, sorted according to the same ordering.

Parameters:
s - sorted set whose elements will comprise the new set.
Throws:
NullPointerException sample code for java.lang.NullPointerException definition code for java.lang.NullPointerException - if the specified sorted set is null.
Method Detail

iterator sample code for java.util.TreeSet.iterator() definition code for java.util.TreeSet.iterator()

public Iterator sample code for java.util.Iterator definition code for java.util.Iterator <E> iterator()
Returns an iterator over the elements in this set. The elements are returned in ascending order.

Specified by:
iterator sample code for java.lang.Iterable.iterator() definition code for java.lang.Iterable.iterator() in interface Iterable sample code for java.lang.Iterable definition code for java.lang.Iterable <E>
Specified by:
iterator sample code for java.util.Collection.iterator() definition code for java.util.Collection.iterator() in interface Collection sample code for java.util.Collection definition code for java.util.Collection <E>
Specified by:
iterator sample code for java.util.Set.iterator() definition code for java.util.Set.iterator() in interface Set sample code for java.util.Set definition code for java.util.Set <E>
Specified by:
iterator sample code for java.util.AbstractCollection.iterator() definition code for java.util.AbstractCollection.iterator() in class AbstractCollection sample code for java.util.AbstractCollection definition code for java.util.AbstractCollection <E>
Returns:
an iterator over the elements in this set.

size sample code for java.util.TreeSet.size() definition code for java.util.TreeSet.size()

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

Specified by:
size sample code for java.util.Collection.size() definition code for java.util.Collection.size() in interface Collection sample code for java.util.Collection definition code for java.util.Collection <E>
Specified by:
size sample code for java.util.Set.size() definition code for java.util.Set.size() in interface Set sample code for java.util.Set definition code for java.util.Set <E>
Specified by:
size sample code for java.util.AbstractCollection.size() definition code for java.util.AbstractCollection.size() in class AbstractCollection sample code for java.util.AbstractCollection definition code for java.util.AbstractCollection <E>
Returns:
the number of elements in this set (its cardinality).

isEmpty sample code for java.util.TreeSet.isEmpty() definition code for java.util.TreeSet.isEmpty()

public boolean isEmpty()
Returns true if this set contains no elements.

Specified by:
isEmpty sample code for java.util.Collection.isEmpty() definition code for java.util.Collection.isEmpty() in interface Collection sample code for java.util.Collection definition code for java.util.Collection <E>
Specified by:
isEmpty sample code for java.util.Set.isEmpty() definition code for java.util.Set.isEmpty() in interface Set sample code for java.util.Set definition code for java.util.Set <E>
Overrides:
isEmpty sample code for java.util.AbstractCollection.isEmpty() definition code for java.util.AbstractCollection.isEmpty() in class AbstractCollection sample code for java.util.AbstractCollection definition code for java.util.AbstractCollection <E>
Returns:
true if this set contains no elements.

contains sample code for java.util.TreeSet.contains(java.lang.Object) definition code for java.util.TreeSet.contains(java.lang.Object)

public boolean contains(Object sample code for java.lang.Object definition code for java.lang.Object  o)
Returns true if this set contains the specified element.

Specified by:
contains sample code for java.util.Collection.contains(java.lang.Object) definition code for java.util.Collection.contains(java.lang.Object) in interface Collection sample code for java.util.Collection definition code for java.util.Collection <E>
Specified by:
contains sample code for java.util.Set.contains(java.lang.Object) definition code for java.util.Set.contains(java.lang.Object) in interface Set sample code for java.util.Set definition code for java.util.Set <E>
Overrides:
contains sample code for java.util.AbstractCollection.contains(java.lang.Object) definition code for java.util.AbstractCollection.contains(java.lang.Object) in class AbstractCollection sample code for java.util.AbstractCollection definition code for java.util.AbstractCollection <E>
Parameters:
o - the object to be checked for containment in this set.
Returns:
true if this set contains the specified element.
Throws:
ClassCastException sample code for java.lang.ClassCastException definition code for java.lang.ClassCastException - if the specified object cannot be compared with the elements currently in the set.

add sample code for java.util.TreeSet.add(E) definition code for java.util.TreeSet.add(E)

public boolean add(E o)
Adds the specified element to this set if it is not already present.

Specified by:
add sample code for java.util.Collection.add(E) definition code for java.util.Collection.add(E) in interface Collection sample code for java.util.Collection definition code for java.util.Collection <E>
Specified by:
add sample code for java.util.Set.add(E) definition code for java.util.Set.add(E) in interface Set sample code for java.util.Set definition code for java.util.Set <E>
Overrides:
add sample code for java.util.AbstractCollection.add(E) definition code for java.util.AbstractCollection.add(E) in class AbstractCollection sample code for java.util.AbstractCollection definition code for java.util.AbstractCollection <E>
Parameters:
o - element to be added to this set.
Returns:
true if the set did not already contain the specified element.
Throws:
ClassCastException sample code for java.lang.ClassCastException definition code for java.lang.ClassCastException - if the specified object cannot be compared with the elements currently in the set.

remove sample code for java.util.TreeSet.remove(java.lang.Object) definition code for java.util.TreeSet.remove(java.lang.Object)

public boolean remove(Object sample code for java.lang.Object definition code for java.lang.Object  o)
Removes the specified element from this set if it is present.

Specified by:
remove sample code for java.util.Collection.remove(java.lang.Object) definition code for java.util.Collection.remove(java.lang.Object) in interface Collection sample code for java.util.Collection definition code for java.util.Collection <E>
Specified by:
remove sample code for java.util.Set.remove(java.lang.Object) definition code for java.util.Set.remove(java.lang.Object) in interface Set sample code for java.util.Set definition code for java.util.Set <E>
Overrides:
remove sample code for java.util.AbstractCollection.remove(java.lang.Object) definition code for java.util.AbstractCollection.remove(java.lang.Object) in class AbstractCollection sample code for java.util.AbstractCollection definition code for java.util.AbstractCollection <E>
Parameters:
o - object to be removed from this set, if present.
Returns:
true if the set contained the specified element.
Throws:
ClassCastException sample code for java.lang.ClassCastException definition code for java.lang.ClassCastException - if the specified object cannot be compared with the elements currently in the set.

clear sample code for java.util.TreeSet.clear() definition code for java.util.TreeSet.clear()

public void clear()
Removes all of the elements from this set.

Specified by:
clear sample code for java.util.Collection.clear() definition code for java.util.Collection.clear() in interface Collection sample code for java.util.Collection definition code for java.util.Collection <E>
Specified by:
clear sample code for java.util.Set.clear() definition code for java.util.Set.clear() in interface Set sample code for java.util.Set definition code for java.util.Set <E>
Overrides:
clear sample code for java.util.AbstractCollection.clear() definition code for java.util.AbstractCollection.clear() in class AbstractCollection sample code for java.util.AbstractCollection definition code for java.util.AbstractCollection <E>

addAll sample code for java.util.TreeSet.addAll(java.util.Collection<? extends E>) definition code for java.util.TreeSet.addAll(java.util.Collection<? extends E>)

public boolean addAll(Collection sample code for java.util.Collection definition code for java.util.Collection <? extends E> c)
Adds all of the elements in the specified collection to this set.

Specified by:
addAll sample code for java.util.Collection.addAll(java.util.Collection) definition code for java.util.Collection.addAll(java.util.Collection) in interface Collection sample code for java.util.Collection definition code for java.util.Collection <E>
Specified by:
addAll sample code for java.util.Set.addAll(java.util.Collection) definition code for java.util.Set.addAll(java.util.Collection) in interface Set sample code for java.util.Set definition code for java.util.Set <E>
Overrides:
addAll sample code for java.util.AbstractCollection.addAll(java.util.Collection) definition code for java.util.AbstractCollection.addAll(java.util.Collection) in class AbstractCollection sample code for java.util.AbstractCollection definition code for java.util.AbstractCollection <E>
Parameters:
c - elements to be added
Returns:
true if this set changed as a result of the call.
Throws:
ClassCastException sample code for java.lang.ClassCastException definition code for java.lang.ClassCastException - if the elements provided cannot be compared with the elements currently in the set.
NullPointerException sample code for java.lang.NullPointerException definition code for java.lang.NullPointerException - of the specified collection is null.
See Also:
AbstractCollection.add(Object) sample code for java.util.AbstractCollection.add(E) definition code for java.util.AbstractCollection.add(E)

subSet sample code for java.util.TreeSet.subSet(E, E) definition code for java.util.TreeSet.subSet(E, E)

public SortedSet sample code for java.util.SortedSet definition code for java.util.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. (If fromElement and toElement are equal, the returned sorted set is empty.) The returned sorted set is backed by this set, so changes in the returned sorted set are reflected in this set, and vice-versa. The returned sorted set supports all optional Set operations.

The sorted set returned by this method will throw an IllegalArgumentException if the user attempts to insert an element outside the specified range.

Note: this method always returns a half-open range (which includes its low endpoint but not its high endpoint). If you need a closed range (which includes both endpoints), and the element type allows for calculation of the successor of a specified value, merely request the subrange from lowEndpoint to successor(highEndpoint). For example, suppose that s is a sorted set of strings. The following idiom obtains a view containing all of the strings in s from low to high, inclusive:

     SortedSet sub = s.subSet(low, high+"\0");
 
A similar technique can be used to generate an open range (which contains neither endpoint). The following idiom obtains a view containing all of the strings in s from low to high, exclusive:
     SortedSet sub = s.subSet(low+"\0", high);
 

Specified by:
subSet sample code for java.util.SortedSet.subSet(E, E) definition code for java.util.SortedSet.subSet(E, E) in interface SortedSet sample code for java.util.SortedSet definition code for java.util.SortedSet <E>
Parameters:
fromElement - low endpoint (inclusive) of the subSet.
toElement - high endpoint (exclusive) of the subSet.
Returns:
a view of the portion of this set whose elements range from fromElement, inclusive, to toElement, exclusive.
Throws:
ClassCastException sample code for java.lang.ClassCastException definition code for java.lang.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).
IllegalArgumentException sample code for java.lang.IllegalArgumentException definition code for java.lang.IllegalArgumentException - if fromElement is greater than toElement.
NullPointerException sample code for java.lang.NullPointerException definition code for java.lang.NullPointerException - if fromElement or toElement is null and this set uses natural order, or its comparator does not tolerate null elements.

headSet sample code for java.util.TreeSet.headSet(E) definition code for java.util.TreeSet.headSet(E)

public SortedSet sample code for java.util.SortedSet definition code for java.util.SortedSet <E> headSet(E toElement)
Returns a view of the portion of this set whose elements are strictly less than toElement. The returned sorted set is backed by this set, so changes in the returned sorted set are reflected in this set, and vice-versa. The returned sorted set supports all optional set operations.

The sorted set returned by this method will throw an IllegalArgumentException if the user attempts to insert an element greater than or equal to toElement.

Note: this method always returns a view that does not contain its (high) endpoint. If you need a view that does contain this endpoint, and the element type allows for calculation of the successor of a specified value, merely request a headSet bounded by successor(highEndpoint). For example, suppose that s is a sorted set of strings. The following idiom obtains a view containing all of the strings in s that are less than or equal to high:

 SortedSet head = s.headSet(high+"\0");

Specified by:
headSet sample code for java.util.SortedSet.headSet(E) definition code for java.util.SortedSet.headSet(E) in interface SortedSet sample code for java.util.SortedSet definition code for java.util.SortedSet <E>
Parameters:
toElement - high endpoint (exclusive) of the headSet.
Returns:
a view of the portion of this set whose elements are strictly less than toElement.
Throws:
ClassCastException sample code for java.lang.ClassCastException definition code for java.lang.ClassCastException - if toElement is not compatible with this set's comparator (or, if the set has no comparator, if toElement does not implement Comparable).
IllegalArgumentException sample code for java.lang.IllegalArgumentException definition code for java.lang.IllegalArgumentException - if this set is itself a subSet, headSet, or tailSet, and toElement is not within the specified range of the subSet, headSet, or tailSet.
NullPointerException sample code for java.lang.NullPointerException definition code for java.lang.NullPointerException - if toElement is null and this set uses natural ordering, or its comparator does not tolerate null elements.

tailSet sample code for java.util.TreeSet.tailSet(E) definition code for java.util.TreeSet.tailSet(E)

public SortedSet sample code for java.util.SortedSet definition code for java.util.SortedSet <E> tailSet(E fromElement)
Returns a view of the portion of this set whose elements are greater than or equal to fromElement. The returned sorted set is backed by this set, so changes in the returned sorted set are reflected in this set, and vice-versa. The returned sorted set supports all optional set operations.

The sorted set returned by this method will throw an IllegalArgumentException if the user attempts to insert an element less than fromElement. Note: this method always returns a view that contains its (low) endpoint. If you need a view that does not contain this endpoint, and the element type allows for calculation of the successor of a specified value, merely request a tailSet bounded by successor(lowEndpoint). For example, suppose that s is a sorted set of strings. The following idiom obtains a view containing all of the strings in s that are strictly greater than low:

     SortedSet tail = s.tailSet(low+"\0");
 

Specified by:
tailSet sample code for java.util.SortedSet.tailSet(E) definition code for java.util.SortedSet.tailSet(E) in interface SortedSet sample code for java.util.SortedSet definition code for java.util.SortedSet <E>
Parameters:
fromElement - low endpoint (inclusive) of the tailSet.
Returns:
a view of the portion of this set whose elements are greater than or equal to fromElement.
Throws:
ClassCastException sample code for java.lang.ClassCastException definition code for java.lang.ClassCastException - if fromElement is not compatible with this set's comparator (or, if the set has no comparator, if fromElement does not implement Comparable).
IllegalArgumentException sample code for java.lang.IllegalArgumentException definition code for java.lang.IllegalArgumentException - if this set is itself a subSet, headSet, or tailSet, and fromElement is not within the specified range of the subSet, headSet, or tailSet.
NullPointerException sample code for java.lang.NullPointerException definition code for java.lang.NullPointerException - if fromElement is null and this set uses natural ordering, or its comparator does not tolerate null elements.

comparator sample code for java.util.TreeSet.comparator() definition code for java.util.TreeSet.comparator()

public Comparator sample code for java.util.Comparator definition code for java.util.Comparator <? super E> comparator()
Returns the comparator used to order this sorted set, or null if this tree set uses its elements natural ordering.

Specified by:
comparator sample code for java.util.SortedSet.comparator() definition code for java.util.SortedSet.comparator() in interface SortedSet sample code for java.util.SortedSet definition code for java.util.SortedSet <E>
Returns:
the comparator used to order this sorted set, or null if this tree set uses its elements natural ordering.

first sample code for java.util.TreeSet.first() definition code for java.util.TreeSet.first()

public E first()
Returns the first (lowest) element currently in this sorted set.

Specified by:
first sample code for java.util.SortedSet.first() definition code for java.util.SortedSet.first() in interface SortedSet sample code for java.util.SortedSet definition code for java.util.SortedSet <E>
Returns:
the first (lowest) element currently in this sorted set.
Throws:
NoSuchElementException sample code for java.util.NoSuchElementException definition code for java.util.NoSuchElementException - sorted set is empty.

last sample code for java.util.TreeSet.last() definition code for java.util.TreeSet.last()

public E last()
Returns the last (highest) element currently in this sorted set.

Specified by:
last sample code for java.util.SortedSet.last() definition code for java.util.SortedSet.last() in interface SortedSet sample code for java.util.SortedSet definition code for java.util.SortedSet <E>
Returns:
the last (highest) element currently in this sorted set.
Throws:
NoSuchElementException sample code for java.util.NoSuchElementException definition code for java.util.NoSuchElementException - sorted set is empty.

clone sample code for java.util.TreeSet.clone() definition code for java.util.TreeSet.clone()

public Object sample code for java.lang.Object definition code for java.lang.Object  clone()
Returns a shallow copy of this TreeSet instance. (The elements themselves are not cloned.)

Overrides:
clone sample code for java.lang.Object.clone() definition code for java.lang.Object.clone() in class Object sample code for java.lang.Object definition code for java.lang.Object
Returns:
a shallow copy of this set.
See Also:
Cloneable sample code for java.lang.Cloneable definition code for java.lang.Cloneable