K
- the type of keys maintained by this mapV
- the type of mapped valuesSerializable
, Cloneable
, Map<K,V>
, NavigableMap<K,V>
, SequencedMap<K,V>
, SortedMap<K,V>
public class TreeMap<K,V> extends AbstractMap<K,V> implements NavigableMap<K,V>, Cloneable, Serializable
NavigableMap
implementation. The map is sorted according to the natural ordering of its keys, or by a Comparator
provided at map creation time, depending on which constructor is used. This implementation provides guaranteed log(n) time cost for the containsKey
, get
, put
and remove
operations. Algorithms are adaptations of those in Cormen, Leiserson, and Rivest's Introduction to Algorithms.
Note that the ordering maintained by a tree map, like any sorted map, and whether or not an explicit comparator is provided, must be consistent with equals
if this sorted map is to correctly implement the Map
interface. (See Comparable
or Comparator
for a precise definition of consistent with equals.) This is so because the Map
interface is defined in terms of the equals
operation, but a sorted map 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 sorted map, equal. The behavior of a sorted map is well-defined even if its ordering is inconsistent with equals
; it just fails to obey the general contract of the Map
interface.
Note that this implementation is not synchronized. If multiple threads access a map concurrently, and at least one of the threads modifies the map structurally, it must be synchronized externally. (A structural modification is any operation that adds or deletes one or more mappings; merely changing the value associated with an existing key is not a structural modification.) This is typically accomplished by synchronizing on some object that naturally encapsulates the map. If no such object exists, the map should be "wrapped" using the Collections.synchronizedSortedMap
method. This is best done at creation time, to prevent accidental unsynchronized access to the map:
SortedMap m = Collections.synchronizedSortedMap(new TreeMap(...));
The iterators returned by the iterator
method of the collections returned by all of this class's "collection view methods" are fail-fast: if the map is structurally 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.
The methods ceilingEntry(K)
, firstEntry()
, floorEntry(K)
, higherEntry(K)
, lastEntry()
, lowerEntry(K)
, pollFirstEntry()
, and pollLastEntry()
return Map.Entry
instances that represent snapshots of mappings as of the time of the call. They do not support mutation of the underlying map via the optional setValue
method.
The putFirst
and putLast
methods of this class throw UnsupportedOperationException
. The encounter order of mappings is determined by the comparison method; therefore, explicit positioning is not supported.
This class is a member of the Java Collections Framework.
AbstractMap.SimpleEntry<K,V>, AbstractMap.SimpleImmutableEntry<K,V>
Constructor | Description |
---|---|
TreeMap() |
Constructs a new, empty tree map, using the natural ordering of its keys. |
TreeMap |
Constructs a new, empty tree map, ordered according to the given comparator. |
TreeMap |
Constructs a new tree map containing the same mappings as the given map, ordered according to the natural ordering of its keys. |
TreeMap |
Constructs a new tree map containing the same mappings and using the same ordering as the specified sorted map. |
Modifier and Type | Method | Description |
---|---|---|
Map.Entry |
ceilingEntry |
Returns a key-value mapping associated with the least key greater than or equal to the given key, or null if there is no such key. |
K |
ceilingKey |
Returns the least key greater than or equal to the given key, or null if there is no such key. |
void |
clear() |
Removes all of the mappings from this map. |
Object |
clone() |
Returns a shallow copy of this TreeMap instance. |
Comparator |
comparator() |
Returns the comparator used to order the keys in this map, or null if this map uses the natural ordering of its keys. |
V |
compute |
Attempts to compute a mapping for the specified key and its current mapped value (or null if there is no current mapping). |
V |
computeIfAbsent |
If the specified key is not already associated with a value (or is mapped to null ), attempts to compute its value using the given mapping function and enters it into this map unless null . |
V |
computeIfPresent |
If the value for the specified key is present and non-null, attempts to compute a new mapping given the key and its current mapped value. |
boolean |
containsKey |
Returns true if this map contains a mapping for the specified key. |
boolean |
containsValue |
Returns true if this map maps one or more keys to the specified value. |
NavigableSet |
descendingKeySet() |
Returns a reverse order NavigableSet view of the keys contained in this map. |
NavigableMap |
descendingMap() |
Returns a reverse order view of the mappings contained in this map. |
Set |
entrySet() |
Returns a Set view of the mappings contained in this map. |
Map.Entry |
firstEntry() |
Returns a key-value mapping associated with the least key in this map, or null if the map is empty. |
K |
firstKey() |
Returns the first (lowest) key currently in this map. |
Map.Entry |
floorEntry |
Returns a key-value mapping associated with the greatest key less than or equal to the given key, or null if there is no such key. |
K |
floorKey |
Returns the greatest key less than or equal to the given key, or null if there is no such key. |
V |
get |
Returns the value to which the specified key is mapped, or null if this map contains no mapping for the key. |
SortedMap |
headMap |
Returns a view of the portion of this map whose keys are strictly less than toKey . |
NavigableMap |
headMap |
Returns a view of the portion of this map whose keys are less than (or equal to, if inclusive is true) toKey . |
Map.Entry |
higherEntry |
Returns a key-value mapping associated with the least key strictly greater than the given key, or null if there is no such key. |
K |
higherKey |
Returns the least key strictly greater than the given key, or null if there is no such key. |
Set |
keySet() |
Returns a Set view of the keys contained in this map. |
Map.Entry |
lastEntry() |
Returns a key-value mapping associated with the greatest key in this map, or null if the map is empty. |
K |
lastKey() |
Returns the last (highest) key currently in this map. |
Map.Entry |
lowerEntry |
Returns a key-value mapping associated with the greatest key strictly less than the given key, or null if there is no such key. |
K |
lowerKey |
Returns the greatest key strictly less than the given key, or null if there is no such key. |
V |
merge |
If the specified key is not already associated with a value or is associated with null, associates it with the given non-null value. |
NavigableSet |
navigableKeySet() |
Returns a NavigableSet view of the keys contained in this map. |
Map.Entry |
pollFirstEntry() |
Removes and returns a key-value mapping associated with the least key in this map, or null if the map is empty. |
Map.Entry |
pollLastEntry() |
Removes and returns a key-value mapping associated with the greatest key in this map, or null if the map is empty. |
V |
put |
Associates the specified value with the specified key in this map. |
void |
putAll |
Copies all of the mappings from the specified map to this map. |
V |
putFirst |
Throws UnsupportedOperationException . |
V |
putLast |
Throws UnsupportedOperationException . |
V |
remove |
Removes the mapping for this key from this TreeMap if present. |
int |
size() |
Returns the number of key-value mappings in this map. |
NavigableMap |
subMap |
Returns a view of the portion of this map whose keys range from fromKey to toKey . |
SortedMap |
subMap |
Returns a view of the portion of this map whose keys range from fromKey , inclusive, to toKey , exclusive. |
SortedMap |
tailMap |
Returns a view of the portion of this map whose keys are greater than or equal to fromKey . |
NavigableMap |
tailMap |
Returns a view of the portion of this map whose keys are greater than (or equal to, if inclusive is true) fromKey . |
Collection |
values() |
Returns a Collection view of the values contained in this map. |
equals, hashCode, isEmpty, toString
equals, forEach, getOrDefault, hashCode, isEmpty, putIfAbsent, remove, replace, replace, replaceAll
reversed
sequencedEntrySet, sequencedKeySet, sequencedValues
public TreeMap()
Comparable
interface. Furthermore, all such keys must be mutually comparable: k1.compareTo(k2)
must not throw a ClassCastException
for any keys k1
and k2
in the map. If the user attempts to put a key into the map that violates this constraint (for example, the user attempts to put a string key into a map whose keys are integers), the put(Object key, Object value)
call will throw a ClassCastException
.public TreeMap(Comparator<? super K> comparator)
comparator.compare(k1,
k2)
must not throw a ClassCastException
for any keys k1
and k2
in the map. If the user attempts to put a key into the map that violates this constraint, the put(Object
key, Object value)
call will throw a ClassCastException
.comparator
- the comparator that will be used to order this map. If null
, the natural ordering of the keys will be used.public TreeMap(Map<? extends K,? extends V> m)
Comparable
interface. Furthermore, all such keys must be mutually comparable: k1.compareTo(k2)
must not throw a ClassCastException
for any keys k1
and k2
in the map. This method runs in n*log(n) time.m
- the map whose mappings are to be placed in this mapClassCastException
- if the keys in m are not Comparable
, or are not mutually comparableNullPointerException
- if the specified map is nullpublic TreeMap(SortedMap<K,? extends V> m)
m
- the sorted map whose mappings are to be placed in this map, and whose comparator is to be used to sort this mapNullPointerException
- if the specified map is nullpublic int size()
public boolean containsKey(Object key)
true
if this map contains a mapping for the specified key.containsKey
in interface Map<K,V>
containsKey
in class AbstractMap<K,V>
key
- key whose presence in this map is to be testedtrue
if this map contains a mapping for the specified keyClassCastException
- if the specified key cannot be compared with the keys currently in the mapNullPointerException
- if the specified key is null and this map uses natural ordering, or its comparator does not permit null keyspublic boolean containsValue(Object value)
true
if this map maps one or more keys to the specified value. More formally, returns true
if and only if this map contains at least one mapping to a value v
such that (value==null ? v==null : value.equals(v))
. This operation will probably require time linear in the map size for most implementations.containsValue
in interface Map<K,V>
containsValue
in class AbstractMap<K,V>
value
- value whose presence in this map is to be testedtrue
if a mapping to value
exists; false
otherwisepublic V get(Object key)
null
if this map contains no mapping for the key. More formally, if this map contains a mapping from a key k
to a value v
such that key
compares equal to k
according to the map's ordering, then this method returns v
; otherwise it returns null
. (There can be at most one such mapping.)
A return value of null
does not necessarily indicate that the map contains no mapping for the key; it's also possible that the map explicitly maps the key to null
. The containsKey
operation may be used to distinguish these two cases.
get
in interface Map<K,V>
get
in class AbstractMap<K,V>
key
- the key whose associated value is to be returnednull
if this map contains no mapping for the keyClassCastException
- if the specified key cannot be compared with the keys currently in the mapNullPointerException
- if the specified key is null and this map uses natural ordering, or its comparator does not permit null keyspublic Comparator<? super K> comparator()
SortedMap
null
if this map uses the natural ordering of its keys.comparator
in interface SortedMap<K,V>
null
if this map uses the natural ordering of its keyspublic K firstKey()
SortedMap
firstKey
in interface SortedMap<K,V>
NoSuchElementException
- if this map is emptypublic K lastKey()
SortedMap
lastKey
in interface SortedMap<K,V>
NoSuchElementException
- if this map is emptypublic V putFirst(K k, V v)
UnsupportedOperationException
. The encounter order induced by this map's comparison method determines the position of mappings, so explicit positioning is not supported.putFirst
in interface SequencedMap<K,V>
putFirst
in interface SortedMap<K,V>
k
- the keyv
- the valueUnsupportedOperationException
- alwayspublic V putLast(K k, V v)
UnsupportedOperationException
. The encounter order induced by this map's comparison method determines the position of mappings, so explicit positioning is not supported.putLast
in interface SequencedMap<K,V>
putLast
in interface SortedMap<K,V>
k
- the keyv
- the valueUnsupportedOperationException
- alwayspublic void putAll(Map<? extends K,? extends V> map)
putAll
in interface Map<K,V>
putAll
in class AbstractMap<K,V>
map
- mappings to be stored in this mapClassCastException
- if the class of a key or value in the specified map prevents it from being stored in this mapNullPointerException
- if the specified map is null or the specified map contains a null key and this map does not permit null keyspublic V put(K key, V value)
put
in interface Map<K,V>
put
in class AbstractMap<K,V>
key
- key with which the specified value is to be associatedvalue
- value to be associated with the specified keykey
, or null
if there was no mapping for key
. (A null
return can also indicate that the map previously associated null
with key
.)ClassCastException
- if the specified key cannot be compared with the keys currently in the mapNullPointerException
- if the specified key is null and this map uses natural ordering, or its comparator does not permit null keyspublic V computeIfAbsent(K key, Function<? super K,? extends V> mappingFunction)
null
), attempts to compute its value using the given mapping function and enters it into this map unless null
. If the mapping function returns null
, no mapping is recorded. If the mapping function itself throws an (unchecked) exception, the exception is rethrown, and no mapping is recorded. The most common usage is to construct a new object serving as an initial mapped value or memoized result, as in:
map.computeIfAbsent(key, k -> new Value(f(k)));
Or to implement a multi-value map, Map<K,Collection<V>>
, supporting multiple values per key:
map.computeIfAbsent(key, k -> new HashSet<V>()).add(v);
The mapping function should not modify this map during computation.
This method will, on a best-effort basis, throw a ConcurrentModificationException
if it is detected that the mapping function modifies this map during computation.
computeIfAbsent
in interface Map<K,V>
key
- key with which the specified value is to be associatedmappingFunction
- the mapping function to compute a valueConcurrentModificationException
- if it is detected that the mapping function modified this mappublic V computeIfPresent(K key, BiFunction<? super K,? super V,? extends V> remappingFunction)
If the remapping function returns null
, the mapping is removed. If the remapping function itself throws an (unchecked) exception, the exception is rethrown, and the current mapping is left unchanged.
The remapping function should not modify this map during computation.
This method will, on a best-effort basis, throw a ConcurrentModificationException
if it is detected that the remapping function modifies this map during computation.
computeIfPresent
in interface Map<K,V>
key
- key with which the specified value is to be associatedremappingFunction
- the remapping function to compute a valueConcurrentModificationException
- if it is detected that the remapping function modified this mappublic V compute(K key, BiFunction<? super K,? super V,? extends V> remappingFunction)
null
if there is no current mapping). For example, to either create or append a String
msg to a value mapping:
map.compute(key, (k, v) -> (v == null) ? msg : v.concat(msg))
(Method merge()
is often simpler to use for such purposes.) If the remapping function returns null
, the mapping is removed (or remains absent if initially absent). If the remapping function itself throws an (unchecked) exception, the exception is rethrown, and the current mapping is left unchanged.
The remapping function should not modify this map during computation.
This method will, on a best-effort basis, throw a ConcurrentModificationException
if it is detected that the remapping function modifies this map during computation.
compute
in interface Map<K,V>
key
- key with which the specified value is to be associatedremappingFunction
- the remapping function to compute a valueConcurrentModificationException
- if it is detected that the remapping function modified this mappublic V merge(K key, V value, BiFunction<? super V,? super V,? extends V> remappingFunction)
null
. This method may be of use when combining multiple mapped values for a key. For example, to either create or append a String msg
to a value mapping:
map.merge(key, msg, String::concat)
If the remapping function returns null
, the mapping is removed. If the remapping function itself throws an (unchecked) exception, the exception is rethrown, and the current mapping is left unchanged.
The remapping function should not modify this map during computation.
This method will, on a best-effort basis, throw a ConcurrentModificationException
if it is detected that the remapping function modifies this map during computation.
merge
in interface Map<K,V>
key
- key with which the resulting value is to be associatedvalue
- the non-null value to be merged with the existing value associated with the key or, if no existing value or a null value is associated with the key, to be associated with the keyremappingFunction
- the remapping function to recompute a value if presentConcurrentModificationException
- if it is detected that the remapping function modified this mappublic V remove(Object key)
remove
in interface Map<K,V>
remove
in class AbstractMap<K,V>
key
- key for which mapping should be removedkey
, or null
if there was no mapping for key
. (A null
return can also indicate that the map previously associated null
with key
.)ClassCastException
- if the specified key cannot be compared with the keys currently in the mapNullPointerException
- if the specified key is null and this map uses natural ordering, or its comparator does not permit null keyspublic void clear()
public Object clone()
TreeMap
instance. (The keys and values themselves are not cloned.)clone
in class AbstractMap<K,V>
public Map.Entry<K,V> firstEntry()
NavigableMap
null
if the map is empty.firstEntry
in interface NavigableMap<K,V>
firstEntry
in interface SequencedMap<K,V>
null
if this map is emptypublic Map.Entry<K,V> lastEntry()
NavigableMap
null
if the map is empty.lastEntry
in interface NavigableMap<K,V>
lastEntry
in interface SequencedMap<K,V>
null
if this map is emptypublic Map.Entry<K,V> pollFirstEntry()
NavigableMap
null
if the map is empty.pollFirstEntry
in interface NavigableMap<K,V>
pollFirstEntry
in interface SequencedMap<K,V>
null
if this map is emptypublic Map.Entry<K,V> pollLastEntry()
NavigableMap
null
if the map is empty.pollLastEntry
in interface NavigableMap<K,V>
pollLastEntry
in interface SequencedMap<K,V>
null
if this map is emptypublic Map.Entry<K,V> lowerEntry(K key)
NavigableMap
null
if there is no such key.lowerEntry
in interface NavigableMap<K,V>
key
- the keykey
, or null
if there is no such keyClassCastException
- if the specified key cannot be compared with the keys currently in the mapNullPointerException
- if the specified key is null and this map uses natural ordering, or its comparator does not permit null keyspublic K lowerKey(K key)
NavigableMap
null
if there is no such key.lowerKey
in interface NavigableMap<K,V>
key
- the keykey
, or null
if there is no such keyClassCastException
- if the specified key cannot be compared with the keys currently in the mapNullPointerException
- if the specified key is null and this map uses natural ordering, or its comparator does not permit null keyspublic Map.Entry<K,V> floorEntry(K key)
NavigableMap
null
if there is no such key.floorEntry
in interface NavigableMap<K,V>
key
- the keykey
, or null
if there is no such keyClassCastException
- if the specified key cannot be compared with the keys currently in the mapNullPointerException
- if the specified key is null and this map uses natural ordering, or its comparator does not permit null keyspublic K floorKey(K key)
NavigableMap
null
if there is no such key.floorKey
in interface NavigableMap<K,V>
key
- the keykey
, or null
if there is no such keyClassCastException
- if the specified key cannot be compared with the keys currently in the mapNullPointerException
- if the specified key is null and this map uses natural ordering, or its comparator does not permit null keyspublic Map.Entry<K,V> ceilingEntry(K key)
NavigableMap
null
if there is no such key.ceilingEntry
in interface NavigableMap<K,V>
key
- the keykey
, or null
if there is no such keyClassCastException
- if the specified key cannot be compared with the keys currently in the mapNullPointerException
- if the specified key is null and this map uses natural ordering, or its comparator does not permit null keyspublic K ceilingKey(K key)
NavigableMap
null
if there is no such key.ceilingKey
in interface NavigableMap<K,V>
key
- the keykey
, or null
if there is no such keyClassCastException
- if the specified key cannot be compared with the keys currently in the mapNullPointerException
- if the specified key is null and this map uses natural ordering, or its comparator does not permit null keyspublic Map.Entry<K,V> higherEntry(K key)
NavigableMap
null
if there is no such key.higherEntry
in interface NavigableMap<K,V>
key
- the keykey
, or null
if there is no such keyClassCastException
- if the specified key cannot be compared with the keys currently in the mapNullPointerException
- if the specified key is null and this map uses natural ordering, or its comparator does not permit null keyspublic K higherKey(K key)
NavigableMap
null
if there is no such key.higherKey
in interface NavigableMap<K,V>
key
- the keykey
, or null
if there is no such keyClassCastException
- if the specified key cannot be compared with the keys currently in the mapNullPointerException
- if the specified key is null and this map uses natural ordering, or its comparator does not permit null keyspublic Set<K> keySet()
Set
view of the keys contained in this map. The set's iterator returns the keys in ascending order. The set's spliterator is late-binding, fail-fast, and additionally reports Spliterator.SORTED
and Spliterator.ORDERED
with an encounter order that is ascending key order. The spliterator's comparator (see Spliterator.getComparator()
) is null
if the tree map's comparator (see comparator()
) is null
. Otherwise, the spliterator's comparator is the same as or imposes the same total ordering as the tree map's comparator.
The set is backed by the map, so changes to the map are reflected in the set, and vice-versa. If the map is modified while an iteration over the set is in progress (except through the iterator's own remove
operation), the results of the iteration are undefined. The set supports element removal, which removes the corresponding mapping from the map, via the Iterator.remove
, Set.remove
, removeAll
, retainAll
, and clear
operations. It does not support the add
or addAll
operations.
public NavigableSet<K> descendingKeySet()
NavigableMap
NavigableSet
view of the keys contained in this map. The set's iterator returns the keys in descending order. The set is backed by the map, so changes to the map are reflected in the set, and vice-versa. If the map is modified while an iteration over the set is in progress (except through the iterator's own
remove
operation), the results of the iteration are undefined. The set supports element removal, which removes the corresponding mapping from the map, via the Iterator.remove
, Set.remove
, removeAll
, retainAll
, and clear
operations. It does not support the add
or addAll
operations.descendingKeySet
in interface NavigableMap<K,V>
public Collection<V> values()
Collection
view of the values contained in this map. The collection's iterator returns the values in ascending order of the corresponding keys. The collection's spliterator is late-binding, fail-fast, and additionally reports Spliterator.ORDERED
with an encounter order that is ascending order of the corresponding keys.
The collection is backed by the map, so changes to the map are reflected in the collection, and vice-versa. If the map is modified while an iteration over the collection is in progress (except through the iterator's own remove
operation), the results of the iteration are undefined. The collection supports element removal, which removes the corresponding mapping from the map, via the Iterator.remove
, Collection.remove
, removeAll
, retainAll
and clear
operations. It does not support the add
or addAll
operations.
public Set<Map.Entry<K,V>> entrySet()
Set
view of the mappings contained in this map. The set's iterator returns the entries in ascending key order. The set's spliterator is late-binding, fail-fast, and additionally reports Spliterator.SORTED
and Spliterator.ORDERED
with an encounter order that is ascending key order.
The set is backed by the map, so changes to the map are reflected in the set, and vice-versa. If the map is modified while an iteration over the set is in progress (except through the iterator's own remove
operation, or through the setValue
operation on a map entry returned by the iterator) the results of the iteration are undefined. The set supports element removal, which removes the corresponding mapping from the map, via the Iterator.remove
, Set.remove
, removeAll
, retainAll
and clear
operations. It does not support the add
or addAll
operations.
public NavigableMap<K,V> descendingMap()
NavigableMap
remove
operation), the results of the iteration are undefined. The returned map has an ordering equivalent to Collections.reverseOrder
(comparator())
. The expression m.descendingMap().descendingMap()
returns a view of m
essentially equivalent to m
.
descendingMap
in interface NavigableMap<K,V>
public NavigableMap<K,V> subMap(K fromKey, boolean fromInclusive, K toKey, boolean toInclusive)
NavigableMap
fromKey
to toKey
. If fromKey
and toKey
are equal, the returned map is empty unless fromInclusive
and toInclusive
are both true. The returned map is backed by this map, so changes in the returned map are reflected in this map, and vice-versa. The returned map supports all optional map operations that this map supports. The returned map will throw an IllegalArgumentException
on an attempt to insert a key outside of its range, or to construct a submap either of whose endpoints lie outside its range.
subMap
in interface NavigableMap<K,V>
fromKey
- low endpoint of the keys in the returned mapfromInclusive
- true
if the low endpoint is to be included in the returned viewtoKey
- high endpoint of the keys in the returned maptoInclusive
- true
if the high endpoint is to be included in the returned viewfromKey
to toKey
ClassCastException
- if fromKey
and toKey
cannot be compared to one another using this map's comparator (or, if the map has no comparator, using natural ordering). Implementations may, but are not required to, throw this exception if fromKey
or toKey
cannot be compared to keys currently in the map.NullPointerException
- if fromKey
or toKey
is null and this map uses natural ordering, or its comparator does not permit null keysIllegalArgumentException
- if fromKey
is greater than toKey
; or if this map itself has a restricted range, and fromKey
or toKey
lies outside the bounds of the rangepublic NavigableMap<K,V> headMap(K toKey, boolean inclusive)
NavigableMap
inclusive
is true) toKey
. The returned map is backed by this map, so changes in the returned map are reflected in this map, and vice-versa. The returned map supports all optional map operations that this map supports. The returned map will throw an IllegalArgumentException
on an attempt to insert a key outside its range.
headMap
in interface NavigableMap<K,V>
toKey
- high endpoint of the keys in the returned mapinclusive
- true
if the high endpoint is to be included in the returned viewinclusive
is true) toKey
ClassCastException
- if toKey
is not compatible with this map's comparator (or, if the map has no comparator, if toKey
does not implement Comparable
). Implementations may, but are not required to, throw this exception if toKey
cannot be compared to keys currently in the map.NullPointerException
- if toKey
is null and this map uses natural ordering, or its comparator does not permit null keysIllegalArgumentException
- if this map itself has a restricted range, and toKey
lies outside the bounds of the rangepublic NavigableMap<K,V> tailMap(K fromKey, boolean inclusive)
NavigableMap
inclusive
is true) fromKey
. The returned map is backed by this map, so changes in the returned map are reflected in this map, and vice-versa. The returned map supports all optional map operations that this map supports. The returned map will throw an IllegalArgumentException
on an attempt to insert a key outside its range.
tailMap
in interface NavigableMap<K,V>
fromKey
- low endpoint of the keys in the returned mapinclusive
- true
if the low endpoint is to be included in the returned viewinclusive
is true) fromKey
ClassCastException
- if fromKey
is not compatible with this map's comparator (or, if the map has no comparator, if fromKey
does not implement Comparable
). Implementations may, but are not required to, throw this exception if fromKey
cannot be compared to keys currently in the map.NullPointerException
- if fromKey
is null and this map uses natural ordering, or its comparator does not permit null keysIllegalArgumentException
- if this map itself has a restricted range, and fromKey
lies outside the bounds of the rangepublic SortedMap<K,V> subMap(K fromKey, K toKey)
NavigableMap
fromKey
, inclusive, to toKey
, exclusive. (If fromKey
and toKey
are equal, the returned map is empty.) The returned map is backed by this map, so changes in the returned map are reflected in this map, and vice-versa. The returned map supports all optional map operations that this map supports. The returned map will throw an IllegalArgumentException
on an attempt to insert a key outside its range.
Equivalent to subMap(fromKey, true, toKey, false)
.
subMap
in interface NavigableMap<K,V>
subMap
in interface SortedMap<K,V>
fromKey
- low endpoint (inclusive) of the keys in the returned maptoKey
- high endpoint (exclusive) of the keys in the returned mapfromKey
, inclusive, to toKey
, exclusiveClassCastException
- if fromKey
and toKey
cannot be compared to one another using this map's comparator (or, if the map has no comparator, using natural ordering). Implementations may, but are not required to, throw this exception if fromKey
or toKey
cannot be compared to keys currently in the map.NullPointerException
- if fromKey
or toKey
is null and this map uses natural ordering, or its comparator does not permit null keysIllegalArgumentException
- if fromKey
is greater than toKey
; or if this map itself has a restricted range, and fromKey
or toKey
lies outside the bounds of the rangepublic SortedMap<K,V> headMap(K toKey)
NavigableMap
toKey
. The returned map is backed by this map, so changes in the returned map are reflected in this map, and vice-versa. The returned map supports all optional map operations that this map supports. The returned map will throw an IllegalArgumentException
on an attempt to insert a key outside its range.
Equivalent to headMap(toKey, false)
.
headMap
in interface NavigableMap<K,V>
headMap
in interface SortedMap<K,V>
toKey
- high endpoint (exclusive) of the keys in the returned maptoKey
ClassCastException
- if toKey
is not compatible with this map's comparator (or, if the map has no comparator, if toKey
does not implement Comparable
). Implementations may, but are not required to, throw this exception if toKey
cannot be compared to keys currently in the map.NullPointerException
- if toKey
is null and this map uses natural ordering, or its comparator does not permit null keysIllegalArgumentException
- if this map itself has a restricted range, and toKey
lies outside the bounds of the rangepublic SortedMap<K,V> tailMap(K fromKey)
NavigableMap
fromKey
. The returned map is backed by this map, so changes in the returned map are reflected in this map, and vice-versa. The returned map supports all optional map operations that this map supports. The returned map will throw an IllegalArgumentException
on an attempt to insert a key outside its range.
Equivalent to tailMap(fromKey, true)
.
tailMap
in interface NavigableMap<K,V>
tailMap
in interface SortedMap<K,V>
fromKey
- low endpoint (inclusive) of the keys in the returned mapfromKey
ClassCastException
- if fromKey
is not compatible with this map's comparator (or, if the map has no comparator, if fromKey
does not implement Comparable
). Implementations may, but are not required to, throw this exception if fromKey
cannot be compared to keys currently in the map.NullPointerException
- if fromKey
is null and this map uses natural ordering, or its comparator does not permit null keysIllegalArgumentException
- if this map itself has a restricted range, and fromKey
lies outside the bounds of the range
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Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
Various third party code in OpenJDK is licensed under different licenses (see Debian package).
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https://docs.oracle.com/en/java/javase/21/docs/api/java.base/java/util/TreeMap.html