Summary: Ctors | Methods | Inherited Methods | [Expand All]

public class

TreeMap

extends AbstractMap<K, V>
implements NavigableMap<K, V>

java.lang.Object
↳	java.util.AbstractMap<K, V>
	↳	java.util.TreeMap<K, V>

Class Overview

TreeMap is an implementation of SortedMap. All optional operations (adding and removing) are supported. The values can be any objects. The keys can be any objects which are comparable to each other either using their natural

Summary

Public Constructors
	TreeMap() Constructs a new empty `TreeMap` instance.
	TreeMap(Comparator<? super K> comparator) Constructs a new empty `TreeMap` instance with the specified comparator.
	TreeMap(Map<? extends K, ? extends V> map) Constructs a new `TreeMap` instance containing the mappings from the specified map and using natural ordering.
	TreeMap(SortedMap<K, ? extends V> map) Constructs a new `TreeMap` instance containing the mappings from the specified SortedMap and using the same comparator.

Public Methods
Entry<K, V>	ceilingEntry(Object key) Answers an entry related with the smallest key greater than or equal to the specified key, or null if no such key.
Object	ceilingKey(Object key) Answers the smallest key greater than or equal to the specified key, or null if no such key.
void	clear() Removes all mappings from this TreeMap, leaving it empty.
Comparator<? super K>	comparator() Returns the comparator used to compare elements in this map.
boolean	containsKey(Object key) Returns whether this map contains the specified key.
boolean	containsValue(Object value) Returns whether this map contains the specified value.
NavigableSet<K>	descendingKeySet() Answers a NavigableSet view of the keys in descending order.
NavigableMap<K, V>	descendingMap() Answers a reverse order view of the map.
Set<Entry<K, V>>	entrySet() Returns a set containing all of the mappings in this map.
Entry<K, V>	firstEntry() Answers the entry with the smallest key, or null if the map is empty.
Object	firstKey() Returns the first key in this map.
Entry<K, V>	floorEntry(Object key) Answers an entry related with the biggest key less than or equal to the specified key, or null if no such key.
Object	floorKey(Object key) Answers the biggest key less than or equal to the specified key, or null if no such key.
V	get(Object key) Returns the value of the mapping with the specified key.
NavigableMap<K, V>	headMap(Object end, boolean inclusive) Answers a view of the head of the map whose keys are smaller than (or equal to, depends on inclusive argument) endKey.
SortedMap<K, V>	headMap(Object endKey) Returns a sorted map over a range of this sorted map with all keys that are less than the specified `endKey`.
Entry<K, V>	higherEntry(Object key) Answers an entry related with the smallest key greater than the specified key, or null if no such key.
Object	higherKey(Object key) Answers the smallest key greater than the specified key, or null if no such key.
Set<K>	keySet() Returns a set of the keys contained in this map.
Entry<K, V>	lastEntry() Answers the entry with the biggest key, or null if the map is empty.
Object	lastKey() Returns the last key in this map.
Entry<K, V>	lowerEntry(Object key) Answers an entry related with the biggest key less than the specified key, or null if no such key.
Object	lowerKey(Object key) Answers the biggest key less than the specified key, or null if no such key.
NavigableSet<K>	navigableKeySet() Answers a NavigableSet view of the keys in ascending order.
Entry<K, V>	pollFirstEntry() Deletes and answers the entry with the smallest key, or null if the map is empty.
Entry<K, V>	pollLastEntry() Deletes and answers the entry with the biggest key, or null if the map is empty.
V	put(K key, V value) Maps the specified key to the specified value.
void	putAll(Map<? extends K, ? extends V> map) Copies all the mappings in the given map to this map.
V	remove(Object key) Removes the mapping with the specified key from this map.
int	size() Returns the number of mappings in this map.
NavigableMap<K, V>	subMap(Object start, boolean startInclusive, Object end, boolean endInclusive) Answers a view of part of the map whose keys is from startKey to endKey.
SortedMap<K, V>	subMap(Object startKey, Object endKey) Returns a sorted map over a range of this sorted map with all keys greater than or equal to the specified `startKey` and less than the specified `endKey`.
SortedMap<K, V>	tailMap(Object startKey) Returns a sorted map over a range of this sorted map with all keys that are greater than or equal to the specified `startKey`.
NavigableMap<K, V>	tailMap(Object start, boolean inclusive) Answers a view of the tail of the map whose keys are bigger than (or equal to, depends on inclusive argument) startKey.
Collection<V>	values() Returns a collection of the values contained in this map.

[Expand]

Inherited Methods

From class java.util.AbstractMap

void	clear() Removes all elements from this map, leaving it empty.
boolean	containsKey(Object key) Returns whether this map contains the specified key.
boolean	containsValue(Object value) Returns whether this map contains the specified value.
abstract Set<Entry<K, V>>	entrySet() Returns a set containing all of the mappings in this map.
boolean	equals(Object object) Compares the specified object to this instance, and returns `true` if the specified object is a map and both maps contain the same mappings.
V	get(Object key) Returns the value of the mapping with the specified key.
int	hashCode() Returns the hash code for this object.
boolean	isEmpty() Returns whether this map is empty.
Set<K>	keySet() Returns a set of the keys contained in this map.
V	put(K key, V value) Maps the specified key to the specified value.
void	putAll(Map<? extends K, ? extends V> map) Copies every mapping in the specified map to this map.
V	remove(Object key) Removes a mapping with the specified key from this Map.
int	size() Returns the number of elements in this map.
String	toString() Returns the string representation of this map.
Collection<V>	values() Returns a collection of the values contained in this map.

From class java.lang.Object

boolean	equals(Object obj) Indicates whether some other object is "equal to" this one.
final Class<?>	getClass() Returns the runtime class of an object.
int	hashCode() Returns a hash code value for the object.
final void	notify() Wakes up a single thread that is waiting on this object's monitor.
final void	notifyAll() Wakes up all threads that are waiting on this object's monitor.
String	toString() Returns a string representation of the object.
final void	wait(long timeout, int nanos) Causes current thread to wait until another thread invokes the `notify()` method or the `notifyAll()` method for this object, or some other thread interrupts the current thread, or a certain amount of real time has elapsed.
final void	wait(long timeout) Causes current thread to wait until either another thread invokes the `notify()` method or the `notifyAll()` method for this object, or a specified amount of time has elapsed.
final void	wait() Causes current thread to wait until another thread invokes the `notify()` method or the `notifyAll()` method for this object.

From interface java.util.Map

abstract void	clear() Removes all elements from this `Map`, leaving it empty.
abstract boolean	containsKey(Object key) Returns whether this `Map` contains the specified key.
abstract boolean	containsValue(Object value) Returns whether this `Map` contains the specified value.
abstract Set<Entry<K, V>>	entrySet() Returns a `Set` containing all of the mappings in this `Map`.
abstract boolean	equals(Object object) Compares the argument to the receiver, and returns `true` if the specified object is a `Map` and both `Map`s contain the same mappings.
abstract V	get(Object key) Returns the value of the mapping with the specified key.
abstract int	hashCode() Returns an integer hash code for the receiver.
abstract boolean	isEmpty() Returns whether this map is empty.
abstract Set<K>	keySet() Returns a set of the keys contained in this `Map`.
abstract V	put(K key, V value) Maps the specified key to the specified value.
abstract void	putAll(Map<? extends K, ? extends V> map) Copies every mapping in the specified `Map` to this `Map`.
abstract V	remove(Object key) Removes a mapping with the specified key from this `Map`.
abstract int	size() Returns the number of mappings in this `Map`.
abstract Collection<V>	values() Returns a `Collection` of the values contained in this `Map`.

From interface java.util.NavigableMap

abstract Entry<K, V>	ceilingEntry(Object key) Answers an entry related with the smallest key greater than or equal to the specified key, or null if no such key.
abstract Object	ceilingKey(Object key) Answers the smallest key greater than or equal to the specified key, or null if no such key.
abstract NavigableSet<K>	descendingKeySet() Answers a NavigableSet view of the keys in descending order.
abstract NavigableMap<K, V>	descendingMap() Answers a reverse order view of the map.
abstract Entry<K, V>	firstEntry() Answers the entry with the smallest key, or null if the map is empty.
abstract Entry<K, V>	floorEntry(Object key) Answers an entry related with the biggest key less than or equal to the specified key, or null if no such key.
abstract Object	floorKey(Object key) Answers the biggest key less than or equal to the specified key, or null if no such key.
abstract NavigableMap<K, V>	headMap(Object endKey, boolean inclusive) Answers a view of the head of the map whose keys are smaller than (or equal to, depends on inclusive argument) endKey.
abstract Entry<K, V>	higherEntry(Object key) Answers an entry related with the smallest key greater than the specified key, or null if no such key.
abstract Object	higherKey(Object key) Answers the smallest key greater than the specified key, or null if no such key.
abstract Entry<K, V>	lastEntry() Answers the entry with the biggest key, or null if the map is empty.
abstract Entry<K, V>	lowerEntry(Object key) Answers an entry related with the biggest key less than the specified key, or null if no such key.
abstract Object	lowerKey(Object key) Answers the biggest key less than the specified key, or null if no such key.
abstract NavigableSet<K>	navigableKeySet() Answers a NavigableSet view of the keys in ascending order.
abstract Entry<K, V>	pollFirstEntry() Deletes and answers the entry with the smallest key, or null if the map is empty.
abstract Entry<K, V>	pollLastEntry() Deletes and answers the entry with the biggest key, or null if the map is empty.
abstract NavigableMap<K, V>	subMap(Object startKey, boolean startInclusive, Object endKey, boolean endInclusive) Answers a view of part of the map whose keys is from startKey to endKey.
abstract NavigableMap<K, V>	tailMap(Object startKey, boolean inclusive) Answers a view of the tail of the map whose keys are bigger than (or equal to, depends on inclusive argument) startKey.

From interface java.util.SortedMap

Public Constructors

public TreeMap ()

Constructs a new empty TreeMap instance.

public TreeMap (Comparator<? super K> comparator)

Constructs a new empty TreeMap instance with the specified comparator.

Parameters

comparator	the comparator to compare keys with.

public TreeMap (Map<? extends K, ? extends V> map)

Constructs a new TreeMap instance containing the mappings from the specified map and using natural ordering.

Parameters

map	the mappings to add.

Throws

ClassCastException	if a key in the specified map does not implement the Comparable interface, or if the keys in the map cannot be compared.

public TreeMap (SortedMap<K, ? extends V> map)

Constructs a new TreeMap instance containing the mappings from the specified SortedMap and using the same comparator.

Parameters

map	the mappings to add.

Public Methods

public Entry<K, V> ceilingEntry (Object key)

Answers an entry related with the smallest key greater than or equal to the specified key, or null if no such key.

Parameters

key	the key

Returns

the entry, or null if no such key

public Object ceilingKey (Object key)

Answers the smallest key greater than or equal to the specified key, or null if no such key.

Parameters

key	the key

Returns

the smallest key greater than or equal to key, or null if no such key

public void clear ()

Removes all mappings from this TreeMap, leaving it empty.

public Comparator<? super K> comparator ()

Returns the comparator used to compare elements in this map.

Returns

the comparator or null if the natural ordering is used.

public boolean containsKey (Object key)

Returns whether this map contains the specified key.

Parameters

key	the key to search for.

Returns

true if this map contains the specified key, false otherwise.

Throws

ClassCastException	if the specified key cannot be compared with the keys in this map.
NullPointerException	if the specified key is `null` and the comparator cannot handle `null` keys.

public boolean containsValue (Object value)

Returns whether this map contains the specified value.

Parameters

value	the value to search for.

Returns

true if this map contains the specified value, false otherwise.

public NavigableSet<K> descendingKeySet ()

Answers a NavigableSet view of the keys in descending order.

Returns

the navigable set view

public NavigableMap<K, V> descendingMap ()

Answers a reverse order view of the map.

Returns

the reverse order view of the map

public Set<Entry<K, V>> entrySet ()

Returns a set containing all of the mappings in this map. Each mapping is an instance of Map.Entry. As the set is backed by this map, changes in one will be reflected in the other. It does not support adding operations.

Returns

a set of the mappings.

public Entry<K, V> firstEntry ()

Answers the entry with the smallest key, or null if the map is empty.

Returns

the entry with the smallest key, or null if the map is empty

public Object firstKey ()

Returns the first key in this map.

Returns

the first key in this map.

Throws

NoSuchElementException	if this map is empty.

public Entry<K, V> floorEntry (Object key)

Answers an entry related with the biggest key less than or equal to the specified key, or null if no such key.

Parameters

key	the key

Returns

the entry, or null if no such key

public Object floorKey (Object key)

Answers the biggest key less than or equal to the specified key, or null if no such key.

Parameters

key	the key

Returns

the biggest key less than or equal to key, or null if no such key

public V get (Object key)

Returns the value of the mapping with the specified key.

Parameters

key	the key.

Returns

the value of the mapping with the specified key.

Throws

ClassCastException	if the key cannot be compared with the keys in this map.
NullPointerException	if the key is `null` and the comparator cannot handle `null`.

public NavigableMap<K, V> headMap (Object end, boolean inclusive)

Answers a view of the head of the map whose keys are smaller than (or equal to, depends on inclusive argument) endKey.

Parameters

end	the end key
inclusive	true if the end key is in the returned map

Returns

the head-map view

public SortedMap<K, V> headMap (Object endKey)

Returns a sorted map over a range of this sorted map with all keys that are less than the specified endKey. Changes to the returned sorted map are reflected in this sorted map and vice versa.

Note: The returned map will not allow an insertion of a key outside the specified range.

Parameters

endKey	the high boundary of the range specified.

Returns

a sorted map where the keys are less than endKey.

Throws

ClassCastException	if the specified key cannot be compared with the keys in this map.
NullPointerException	if the specified key is `null` and the comparator cannot handle `null` keys.
IllegalArgumentException	if this map is itself a sorted map over a range of another map and the specified key is outside of its range.

public Entry<K, V> higherEntry (Object key)

Answers an entry related with the smallest key greater than the specified key, or null if no such key.

Parameters

key	the key

Returns

the entry, or null if no such key

public Object higherKey (Object key)

Answers the smallest key greater than the specified key, or null if no such key.

Parameters

key	the key

Returns

the smallest key greater than key, or null if no such key

public Set<K> keySet ()

Returns a set of the keys contained in this map. The set is backed by this map so changes to one are reflected by the other. The set does not support adding.

Returns

a set of the keys.

public Entry<K, V> lastEntry ()

Answers the entry with the biggest key, or null if the map is empty.

Returns

the entry with the biggest key, or null if the map is empty

public Object lastKey ()

Returns the last key in this map.

Returns

the last key in this map.

Throws

NoSuchElementException	if this map is empty.

public Entry<K, V> lowerEntry (Object key)

Answers an entry related with the biggest key less than the specified key, or null if no such key.

Parameters

key	the key

Returns

the entry, or null if no such key

public Object lowerKey (Object key)

Answers the biggest key less than the specified key, or null if no such key.

Parameters

key	the key

Returns

the biggest key less than key, or null if no such key

public NavigableSet<K> navigableKeySet ()

Answers a NavigableSet view of the keys in ascending order.

Returns

the navigable set view

public Entry<K, V> pollFirstEntry ()

Deletes and answers the entry with the smallest key, or null if the map is empty.

Returns

the entry with the smallest key, or null if the map is empty

public Entry<K, V> pollLastEntry ()

Deletes and answers the entry with the biggest key, or null if the map is empty.

Returns

the entry with the biggest key, or null if the map is empty

public V put (K key, V value)

Maps the specified key to the specified value.

Parameters

key	the key.
value	the value.

Returns

the value of any previous mapping with the specified key or null if there was no mapping.

Throws

ClassCastException	if the specified key cannot be compared with the keys in this map.
NullPointerException	if the specified key is `null` and the comparator cannot handle `null` keys.

public void putAll (Map<? extends K, ? extends V> map)

Copies all the mappings in the given map to this map. These mappings will replace all mappings that this map had for any of the keys currently in the given map.

Parameters

map	the map to copy mappings from.

Throws

ClassCastException	if a key in the specified map cannot be compared with the keys in this map.
NullPointerException	if a key in the specified map is `null` and the comparator cannot handle `null` keys.

public V remove (Object key)

Removes the mapping with the specified key from this map.

Parameters

key	the key of the mapping to remove.

Returns

the value of the removed mapping or null if no mapping for the specified key was found.

Throws

ClassCastException	if the specified key cannot be compared with the keys in this map.
NullPointerException	if the specified key is `null` and the comparator cannot handle `null` keys.

public int size ()

Returns the number of mappings in this map.

Returns

the number of mappings in this map.

public NavigableMap<K, V> subMap (Object start, boolean startInclusive, Object end, boolean endInclusive)

Answers a view of part of the map whose keys is from startKey to endKey.

Parameters

start	the start key
startInclusive	true if the start key is in the returned map
end	the end key
endInclusive	true if the end key is in the returned map

Returns

the sub-map view

public SortedMap<K, V> subMap (Object startKey, Object endKey)

Returns a sorted map over a range of this sorted map with all keys greater than or equal to the specified startKey and less than the specified endKey. Changes to the returned sorted map are reflected in this sorted map and vice versa.

Note: The returned map will not allow an insertion of a key outside the specified range.

Parameters

startKey	the low boundary of the range (inclusive).
endKey	the high boundary of the range (exclusive),

Returns

a sorted map with the key from the specified range.

Throws

ClassCastException	if the start or end key cannot be compared with the keys in this map.
NullPointerException	if the start or end key is `null` and the comparator cannot handle `null` keys.
IllegalArgumentException	if the start key is greater than the end key, or if this map is itself a sorted map over a range of another sorted map and the specified range is outside of its range.

public SortedMap<K, V> tailMap (Object startKey)

Returns a sorted map over a range of this sorted map with all keys that are greater than or equal to the specified startKey. Changes to the returned sorted map are reflected in this sorted map and vice versa.

Note: The returned map will not allow an insertion of a key outside the specified range.

Parameters

startKey	the low boundary of the range specified.

Returns

a sorted map where the keys are greater or equal to startKey.

Throws

ClassCastException	if the specified key cannot be compared with the keys in this map.
NullPointerException	if the specified key is `null` and the comparator cannot handle `null` keys.
IllegalArgumentException	if this map itself a sorted map over a range of another map and the specified key is outside of its range.

public NavigableMap<K, V> tailMap (Object start, boolean inclusive)

Answers a view of the tail of the map whose keys are bigger than (or equal to, depends on inclusive argument) startKey.

Parameters

start	the start key
inclusive	true if the start key is in the returned map

Returns

the tail-map view

public Collection<V> values ()

Returns a collection of the values contained in this map. The collection is backed by this map so changes to one are reflected by the other. The collection supports remove, removeAll, retainAll and clear operations, and it does not support add or addAll operations.

This method returns a collection which is the subclass of AbstractCollection. The iterator method of this subclass returns a "wrapper object" over the iterator of map's entrySet(). The size method wraps the map's size method and the contains method wraps the map's containsValue method.

The collection is created when this method is called for the first time and returned in response to all subsequent calls. This method may return different collections when multiple concurrent calls occur, since no synchronization is performed.

Returns

a collection of the values contained in this map.

Interfaces

Classes

Exceptions

TreeMap

Class Overview

Summary

Public Constructors

public TreeMap ()

public TreeMap (Comparator<? super K> comparator)

Parameters

public TreeMap (Map<? extends K, ? extends V> map)

Parameters

Throws

public TreeMap (SortedMap<K, ? extends V> map)

Parameters

Public Methods

public Entry<K, V> ceilingEntry (Object key)

Parameters

Returns

See Also

public Object ceilingKey (Object key)

Parameters

Returns

See Also

public void clear ()

See Also

public Comparator<? super K> comparator ()

Returns

public boolean containsKey (Object key)

Parameters

Returns

Throws

public boolean containsValue (Object value)

Parameters

Returns

public NavigableSet<K> descendingKeySet ()

Returns

See Also

public NavigableMap<K, V> descendingMap ()

Returns

See Also

public Set<Entry<K, V>> entrySet ()

Returns

public Entry<K, V> firstEntry ()

Returns

See Also

public Object firstKey ()

Returns

Throws

public Entry<K, V> floorEntry (Object key)

Parameters

Returns

See Also

public Object floorKey (Object key)

Parameters

Returns

See Also

public V get (Object key)

Parameters

Returns

Throws

public NavigableMap<K, V> headMap (Object end, boolean inclusive)

Parameters

Returns

See Also

public SortedMap<K, V> headMap (Object endKey)

Parameters

Returns

Throws

public Entry<K, V> higherEntry (Object key)

Parameters

Returns

See Also

public Object higherKey (Object key)

Parameters

Returns

See Also

public Set<K> keySet ()

Returns

public Entry<K, V> lastEntry ()