- java.lang.Object
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- java.util.AbstractMap<K,V>
-
- java.util.concurrent.ConcurrentSkipListMap<K,V>
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- Type Parameters:
K
- the type of keys maintained by this mapV
- the type of mapped values
- All Implemented Interfaces:
- Serializable, Cloneable, ConcurrentMap<K,V>, ConcurrentNavigableMap<K,V>, Map<K,V>, NavigableMap<K,V>, SortedMap<K,V>
public class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V> implements ConcurrentNavigableMap<K,V>, Cloneable, Serializable
A scalable concurrentConcurrentNavigableMap
implementation. The map is sorted according to the natural ordering of its keys, or by aComparator
provided at map creation time, depending on which constructor is used.This class implements a concurrent variant of SkipLists providing expected average log(n) time cost for the containsKey, get, put and remove operations and their variants. Insertion, removal, update, and access operations safely execute concurrently by multiple threads. Iterators are weakly consistent, returning elements reflecting the state of the map at some point at or since the creation of the iterator. They do not throw
ConcurrentModificationException
, and may proceed concurrently with other operations. Ascending key ordered views and their iterators are faster than descending ones.All Map.Entry pairs returned by methods in this class and its views represent snapshots of mappings at the time they were produced. They do not support the Entry.setValue method. (Note however that it is possible to change mappings in the associated map using put, putIfAbsent, or replace, depending on exactly which effect you need.)
Beware that, unlike in most collections, the size method is not a constant-time operation. Because of the asynchronous nature of these maps, determining the current number of elements requires a traversal of the elements, and so may report inaccurate results if this collection is modified during traversal. Additionally, the bulk operations putAll, equals, toArray, containsValue, and clear are not guaranteed to be performed atomically. For example, an iterator operating concurrently with a putAll operation might view only some of the added elements.
This class and its views and iterators implement all of the optional methods of the
Map
andIterator
interfaces. Like most other concurrent collections, this class does not permit the use of null keys or values because some null return values cannot be reliably distinguished from the absence of elements.This class is a member of the Java Collections Framework.
- Since:
- 1.6
- See Also:
- Serialized Form
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Nested Class Summary
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Nested classes/interfaces inherited from class java.util.AbstractMap
AbstractMap.SimpleEntry<K,V>, AbstractMap.SimpleImmutableEntry<K,V>
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Constructor Summary
Constructors Constructor and Description ConcurrentSkipListMap()
Constructs a new, empty map, sorted according to the natural ordering of the keys.ConcurrentSkipListMap(Comparator<? super K> comparator)
Constructs a new, empty map, sorted according to the specified comparator.ConcurrentSkipListMap(Map<? extends K,? extends V> m)
Constructs a new map containing the same mappings as the given map, sorted according to the natural ordering of the keys.ConcurrentSkipListMap(SortedMap<K,? extends V> m)
Constructs a new map containing the same mappings and using the same ordering as the specified sorted map.
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Method Summary
Methods Modifier and Type Method and Description Map.Entry<K,V>
ceilingEntry(K key)
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 entry.K
ceilingKey(K key)
Returns the least key greater than or equal to the given key, ornull
if there is no such key.void
clear()
Removes all of the mappings from this map.ConcurrentSkipListMap<K,V>
clone()
Returns a shallow copy of this ConcurrentSkipListMap instance.Comparator<? super K>
comparator()
Returns the comparator used to order the keys in this map, ornull
if this map uses the natural ordering of its keys.boolean
containsKey(Object key)
Returns true if this map contains a mapping for the specified key.boolean
containsValue(Object value)
Returns true if this map maps one or more keys to the specified value.NavigableSet<K>
descendingKeySet()
Returns a reverse orderNavigableSet
view of the keys contained in this map.ConcurrentNavigableMap<K,V>
descendingMap()
Returns a reverse order view of the mappings contained in this map.Set<Map.Entry<K,V>>
entrySet()
Returns aSet
view of the mappings contained in this map.boolean
equals(Object o)
Compares the specified object with this map for equality.Map.Entry<K,V>
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<K,V>
floorEntry(K key)
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(K key)
Returns the greatest key less than or equal to the given key, ornull
if there is no such key.V
get(Object key)
Returns the value to which the specified key is mapped, ornull
if this map contains no mapping for the key.ConcurrentNavigableMap<K,V>
headMap(K toKey)
Returns a view of the portion of this map whose keys are strictly less thantoKey
.ConcurrentNavigableMap<K,V>
headMap(K toKey, boolean inclusive)
Returns a view of the portion of this map whose keys are less than (or equal to, ifinclusive
is true)toKey
.Map.Entry<K,V>
higherEntry(K key)
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(K key)
Returns the least key strictly greater than the given key, ornull
if there is no such key.boolean
isEmpty()
Returns true if this map contains no key-value mappings.NavigableSet<K>
keySet()
Returns aNavigableSet
view of the keys contained in this map.Map.Entry<K,V>
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<K,V>
lowerEntry(K key)
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(K key)
Returns the greatest key strictly less than the given key, ornull
if there is no such key.NavigableSet<K>
navigableKeySet()
Returns aNavigableSet
view of the keys contained in this map.Map.Entry<K,V>
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<K,V>
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(K key, V value)
Associates the specified value with the specified key in this map.V
putIfAbsent(K key, V value)
If the specified key is not already associated with a value, associate it with the given value.V
remove(Object key)
Removes the mapping for the specified key from this map if present.boolean
remove(Object key, Object value)
Removes the entry for a key only if currently mapped to a given value.V
replace(K key, V value)
Replaces the entry for a key only if currently mapped to some value.boolean
replace(K key, V oldValue, V newValue)
Replaces the entry for a key only if currently mapped to a given value.int
size()
Returns the number of key-value mappings in this map.ConcurrentNavigableMap<K,V>
subMap(K fromKey, boolean fromInclusive, K toKey, boolean toInclusive)
Returns a view of the portion of this map whose keys range fromfromKey
totoKey
.ConcurrentNavigableMap<K,V>
subMap(K fromKey, K toKey)
Returns a view of the portion of this map whose keys range fromfromKey
, inclusive, totoKey
, exclusive.ConcurrentNavigableMap<K,V>
tailMap(K fromKey)
Returns a view of the portion of this map whose keys are greater than or equal tofromKey
.ConcurrentNavigableMap<K,V>
tailMap(K fromKey, boolean inclusive)
Returns a view of the portion of this map whose keys are greater than (or equal to, ifinclusive
is true)fromKey
.Collection<V>
values()
Returns aCollection
view of the values contained in this map.
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Constructor Detail
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ConcurrentSkipListMap
public ConcurrentSkipListMap()
Constructs a new, empty map, sorted according to the natural ordering of the keys.
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ConcurrentSkipListMap
public ConcurrentSkipListMap(Comparator<? super K> comparator)
Constructs a new, empty map, sorted according to the specified comparator.- Parameters:
comparator
- the comparator that will be used to order this map. If null, the natural ordering of the keys will be used.
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ConcurrentSkipListMap
public ConcurrentSkipListMap(Map<? extends K,? extends V> m)
Constructs a new map containing the same mappings as the given map, sorted according to the natural ordering of the keys.- Parameters:
m
- the map whose mappings are to be placed in this map- Throws:
ClassCastException
- if the keys in m are notComparable
, or are not mutually comparableNullPointerException
- if the specified map or any of its keys or values are null
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ConcurrentSkipListMap
public ConcurrentSkipListMap(SortedMap<K,? extends V> m)
Constructs a new map containing the same mappings and using the same ordering as the specified sorted map.- Parameters:
m
- the sorted map whose mappings are to be placed in this map, and whose comparator is to be used to sort this map- Throws:
NullPointerException
- if the specified sorted map or any of its keys or values are null
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Method Detail
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clone
public ConcurrentSkipListMap<K,V> clone()
Returns a shallow copy of this ConcurrentSkipListMap instance. (The keys and values themselves are not cloned.)- Overrides:
clone
in classAbstractMap<K,V>
- Returns:
- a shallow copy of this map
- See Also:
Cloneable
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containsKey
public boolean containsKey(Object key)
Returns true if this map contains a mapping for the specified key.- Specified by:
containsKey
in interfaceMap<K,V>
- Overrides:
containsKey
in classAbstractMap<K,V>
- Parameters:
key
- key whose presence in this map is to be tested- Returns:
- true if this map contains a mapping for the specified key
- Throws:
ClassCastException
- if the specified key cannot be compared with the keys currently in the mapNullPointerException
- if the specified key is null
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get
public V get(Object key)
Returns the value to which the specified key is mapped, ornull
if this map contains no mapping for the key.More formally, if this map contains a mapping from a key
k
to a valuev
such thatkey
compares equal tok
according to the map's ordering, then this method returnsv
; otherwise it returnsnull
. (There can be at most one such mapping.)- Specified by:
get
in interfaceMap<K,V>
- Overrides:
get
in classAbstractMap<K,V>
- Parameters:
key
- the key whose associated value is to be returned- Returns:
- the value to which the specified key is mapped, or
null
if this map contains no mapping for the key - Throws:
ClassCastException
- if the specified key cannot be compared with the keys currently in the mapNullPointerException
- if the specified key is null
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put
public V put(K key, V value)
Associates the specified value with the specified key in this map. If the map previously contained a mapping for the key, the old value is replaced.- Specified by:
put
in interfaceMap<K,V>
- Overrides:
put
in classAbstractMap<K,V>
- Parameters:
key
- key with which the specified value is to be associatedvalue
- value to be associated with the specified key- Returns:
- the previous value associated with the specified key, or null if there was no mapping for the key
- Throws:
ClassCastException
- if the specified key cannot be compared with the keys currently in the mapNullPointerException
- if the specified key or value is null
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remove
public V remove(Object key)
Removes the mapping for the specified key from this map if present.- Specified by:
remove
in interfaceMap<K,V>
- Overrides:
remove
in classAbstractMap<K,V>
- Parameters:
key
- key for which mapping should be removed- Returns:
- the previous value associated with the specified key, or null if there was no mapping for the key
- Throws:
ClassCastException
- if the specified key cannot be compared with the keys currently in the mapNullPointerException
- if the specified key is null
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containsValue
public boolean containsValue(Object value)
Returns true if this map maps one or more keys to the specified value. This operation requires time linear in the map size. Additionally, it is possible for the map to change during execution of this method, in which case the returned result may be inaccurate.- Specified by:
containsValue
in interfaceMap<K,V>
- Overrides:
containsValue
in classAbstractMap<K,V>
- Parameters:
value
- value whose presence in this map is to be tested- Returns:
- true if a mapping to value exists; false otherwise
- Throws:
NullPointerException
- if the specified value is null
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size
public int size()
Returns the number of key-value mappings in this map. If this map contains more than Integer.MAX_VALUE elements, it returns Integer.MAX_VALUE.Beware that, unlike in most collections, this method is NOT a constant-time operation. Because of the asynchronous nature of these maps, determining the current number of elements requires traversing them all to count them. Additionally, it is possible for the size to change during execution of this method, in which case the returned result will be inaccurate. Thus, this method is typically not very useful in concurrent applications.
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isEmpty
public boolean isEmpty()
Returns true if this map contains no key-value mappings.
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clear
public void clear()
Removes all of the mappings from this map.
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keySet
public NavigableSet<K> keySet()
Returns aNavigableSet
view of the keys contained in this map. The set's iterator returns the keys in ascending order. The set is backed by the map, so changes to the map are reflected in the set, and vice-versa. The set supports element removal, which removes the corresponding mapping from the map, via theIterator.remove
,Set.remove
,removeAll
,retainAll
, andclear
operations. It does not support theadd
oraddAll
operations.The view's
iterator
is a "weakly consistent" iterator that will never throwConcurrentModificationException
, and guarantees to traverse elements as they existed upon construction of the iterator, and may (but is not guaranteed to) reflect any modifications subsequent to construction.This method is equivalent to method
navigableKeySet
.
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navigableKeySet
public NavigableSet<K> navigableKeySet()
Description copied from interface:ConcurrentNavigableMap
Returns aNavigableSet
view of the keys contained in this map. The set's iterator returns the keys in ascending order. The set is backed by the map, so changes to the map are reflected in the set, and vice-versa. The set supports element removal, which removes the corresponding mapping from the map, via theIterator.remove
,Set.remove
,removeAll
,retainAll
, andclear
operations. It does not support theadd
oraddAll
operations.The view's
iterator
is a "weakly consistent" iterator that will never throwConcurrentModificationException
, and guarantees to traverse elements as they existed upon construction of the iterator, and may (but is not guaranteed to) reflect any modifications subsequent to construction.- Specified by:
navigableKeySet
in interfaceConcurrentNavigableMap<K,V>
- Specified by:
navigableKeySet
in interfaceNavigableMap<K,V>
- Returns:
- a navigable set view of the keys in this map
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values
public Collection<V> values()
Returns aCollection
view of the values contained in this map. The collection's iterator returns the values in 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. 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.The view's iterator is a "weakly consistent" iterator that will never throw
ConcurrentModificationException
, and guarantees to traverse elements as they existed upon construction of the iterator, and may (but is not guaranteed to) reflect any modifications subsequent to construction.
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entrySet
public Set<Map.Entry<K,V>> entrySet()
Returns aSet
view of the mappings contained in this map. The set's iterator returns the entries in ascending key order. The set is backed by the map, so changes to the map are reflected in the set, and vice-versa. 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.The view's iterator is a "weakly consistent" iterator that will never throw
ConcurrentModificationException
, and guarantees to traverse elements as they existed upon construction of the iterator, and may (but is not guaranteed to) reflect any modifications subsequent to construction.The Map.Entry elements returned by iterator.next() do not support the setValue operation.
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descendingMap
public ConcurrentNavigableMap<K,V> descendingMap()
Description copied from interface:ConcurrentNavigableMap
Returns a reverse order view of the mappings contained in this map. The descending map is backed by this map, so changes to the map are reflected in the descending map, and vice-versa.The returned map has an ordering equivalent to
Collections.reverseOrder
(comparator()). The expressionm.descendingMap().descendingMap()
returns a view ofm
essentially equivalent tom
.- Specified by:
descendingMap
in interfaceConcurrentNavigableMap<K,V>
- Specified by:
descendingMap
in interfaceNavigableMap<K,V>
- Returns:
- a reverse order view of this map
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descendingKeySet
public NavigableSet<K> descendingKeySet()
Description copied from interface:ConcurrentNavigableMap
Returns a reverse orderNavigableSet
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. The set supports element removal, which removes the corresponding mapping from the map, via theIterator.remove
,Set.remove
,removeAll
,retainAll
, andclear
operations. It does not support theadd
oraddAll
operations.The view's
iterator
is a "weakly consistent" iterator that will never throwConcurrentModificationException
, and guarantees to traverse elements as they existed upon construction of the iterator, and may (but is not guaranteed to) reflect any modifications subsequent to construction.- Specified by:
descendingKeySet
in interfaceConcurrentNavigableMap<K,V>
- Specified by:
descendingKeySet
in interfaceNavigableMap<K,V>
- Returns:
- a reverse order navigable set view of the keys in this map
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equals
public boolean equals(Object o)
Compares the specified object with this map for equality. Returns true if the given object is also a map and the two maps represent the same mappings. More formally, two maps m1 and m2 represent the same mappings if m1.entrySet().equals(m2.entrySet()). This operation may return misleading results if either map is concurrently modified during execution of this method.- Specified by:
equals
in interfaceMap<K,V>
- Overrides:
equals
in classAbstractMap<K,V>
- Parameters:
o
- object to be compared for equality with this map- Returns:
- true if the specified object is equal to this map
- See Also:
Object.hashCode()
,HashMap
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putIfAbsent
public V putIfAbsent(K key, V value)
If the specified key is not already associated with a value, associate it with the given value. This is equivalent toif (!map.containsKey(key)) return map.put(key, value); else return map.get(key);
except that the action is performed atomically.- Specified by:
putIfAbsent
in interfaceConcurrentMap<K,V>
- Parameters:
key
- key with which the specified value is to be associatedvalue
- value to be associated with the specified key- Returns:
- the previous value associated with the specified key, or null if there was no mapping for the key
- Throws:
ClassCastException
- if the specified key cannot be compared with the keys currently in the mapNullPointerException
- if the specified key or value is null
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remove
public boolean remove(Object key, Object value)
Removes the entry for a key only if currently mapped to a given value. This is equivalent toif (map.containsKey(key) && map.get(key).equals(value)) { map.remove(key); return true; } else return false;
except that the action is performed atomically.- Specified by:
remove
in interfaceConcurrentMap<K,V>
- Parameters:
key
- key with which the specified value is associatedvalue
- value expected to be associated with the specified key- Returns:
- true if the value was removed
- Throws:
ClassCastException
- if the specified key cannot be compared with the keys currently in the mapNullPointerException
- if the specified key is null
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replace
public boolean replace(K key, V oldValue, V newValue)
Replaces the entry for a key only if currently mapped to a given value. This is equivalent toif (map.containsKey(key) && map.get(key).equals(oldValue)) { map.put(key, newValue); return true; } else return false;
except that the action is performed atomically.- Specified by:
replace
in interfaceConcurrentMap<K,V>
- Parameters:
key
- key with which the specified value is associatedoldValue
- value expected to be associated with the specified keynewValue
- value to be associated with the specified key- Returns:
- true if the value was replaced
- Throws:
ClassCastException
- if the specified key cannot be compared with the keys currently in the mapNullPointerException
- if any of the arguments are null
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replace
public V replace(K key, V value)
Replaces the entry for a key only if currently mapped to some value. This is equivalent toif (map.containsKey(key)) { return map.put(key, value); } else return null;
except that the action is performed atomically.- Specified by:
replace
in interfaceConcurrentMap<K,V>
- Parameters:
key
- key with which the specified value is associatedvalue
- value to be associated with the specified key- Returns:
- the previous value associated with the specified key, or null if there was no mapping for the key
- Throws:
ClassCastException
- if the specified key cannot be compared with the keys currently in the mapNullPointerException
- if the specified key or value is null
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comparator
public Comparator<? super K> comparator()
Description copied from interface:SortedMap
Returns the comparator used to order the keys in this map, ornull
if this map uses the natural ordering of its keys.- Specified by:
comparator
in interfaceSortedMap<K,V>
- Returns:
- the comparator used to order the keys in this map,
or
null
if this map uses the natural ordering of its keys
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firstKey
public K firstKey()
Description copied from interface:SortedMap
Returns the first (lowest) key currently in this map.- Specified by:
firstKey
in interfaceSortedMap<K,V>
- Returns:
- the first (lowest) key currently in this map
- Throws:
NoSuchElementException
- if this map is empty
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lastKey
public K lastKey()
Description copied from interface:SortedMap
Returns the last (highest) key currently in this map.- Specified by:
lastKey
in interfaceSortedMap<K,V>
- Returns:
- the last (highest) key currently in this map
- Throws:
NoSuchElementException
- if this map is empty
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subMap
public ConcurrentNavigableMap<K,V> subMap(K fromKey, boolean fromInclusive, K toKey, boolean toInclusive)
Description copied from interface:NavigableMap
Returns a view of the portion of this map whose keys range fromfromKey
totoKey
. IffromKey
andtoKey
are equal, the returned map is empty unlessfromInclusive
andtoInclusive
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.- Specified by:
subMap
in interfaceConcurrentNavigableMap<K,V>
- Specified by:
subMap
in interfaceNavigableMap<K,V>
- Parameters:
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 view- Returns:
- a view of the portion of this map whose keys range from
fromKey
totoKey
- Throws:
ClassCastException
- iffromKey
andtoKey
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 iffromKey
ortoKey
cannot be compared to keys currently in the map.NullPointerException
- iffromKey
ortoKey
is nullIllegalArgumentException
- iffromKey
is greater thantoKey
; or if this map itself has a restricted range, andfromKey
ortoKey
lies outside the bounds of the range
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headMap
public ConcurrentNavigableMap<K,V> headMap(K toKey, boolean inclusive)
Description copied from interface:NavigableMap
Returns a view of the portion of this map whose keys are less than (or equal to, ifinclusive
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.- Specified by:
headMap
in interfaceConcurrentNavigableMap<K,V>
- Specified by:
headMap
in interfaceNavigableMap<K,V>
- Parameters:
toKey
- high endpoint of the keys in the returned mapinclusive
-true
if the high endpoint is to be included in the returned view- Returns:
- a view of the portion of this map whose keys are less than
(or equal to, if
inclusive
is true)toKey
- Throws:
ClassCastException
- iftoKey
is not compatible with this map's comparator (or, if the map has no comparator, iftoKey
does not implementComparable
). Implementations may, but are not required to, throw this exception iftoKey
cannot be compared to keys currently in the map.NullPointerException
- iftoKey
is nullIllegalArgumentException
- if this map itself has a restricted range, andtoKey
lies outside the bounds of the range
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tailMap
public ConcurrentNavigableMap<K,V> tailMap(K fromKey, boolean inclusive)
Description copied from interface:NavigableMap
Returns a view of the portion of this map whose keys are greater than (or equal to, ifinclusive
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.- Specified by:
tailMap
in interfaceConcurrentNavigableMap<K,V>
- Specified by:
tailMap
in interfaceNavigableMap<K,V>
- Parameters:
fromKey
- low endpoint of the keys in the returned mapinclusive
-true
if the low endpoint is to be included in the returned view- Returns:
- a view of the portion of this map whose keys are greater than
(or equal to, if
inclusive
is true)fromKey
- Throws:
ClassCastException
- iffromKey
is not compatible with this map's comparator (or, if the map has no comparator, iffromKey
does not implementComparable
). Implementations may, but are not required to, throw this exception iffromKey
cannot be compared to keys currently in the map.NullPointerException
- iffromKey
is nullIllegalArgumentException
- if this map itself has a restricted range, andfromKey
lies outside the bounds of the range
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subMap
public ConcurrentNavigableMap<K,V> subMap(K fromKey, K toKey)
Description copied from interface:NavigableMap
Returns a view of the portion of this map whose keys range fromfromKey
, inclusive, totoKey
, exclusive. (IffromKey
andtoKey
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)
.- Specified by:
subMap
in interfaceConcurrentNavigableMap<K,V>
- Specified by:
subMap
in interfaceNavigableMap<K,V>
- Specified by:
subMap
in interfaceSortedMap<K,V>
- Parameters:
fromKey
- low endpoint (inclusive) of the keys in the returned maptoKey
- high endpoint (exclusive) of the keys in the returned map- Returns:
- a view of the portion of this map whose keys range from
fromKey
, inclusive, totoKey
, exclusive - Throws:
ClassCastException
- iffromKey
andtoKey
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 iffromKey
ortoKey
cannot be compared to keys currently in the map.NullPointerException
- iffromKey
ortoKey
is nullIllegalArgumentException
- iffromKey
is greater thantoKey
; or if this map itself has a restricted range, andfromKey
ortoKey
lies outside the bounds of the range
-
headMap
public ConcurrentNavigableMap<K,V> headMap(K toKey)
Description copied from interface:NavigableMap
Returns a view of the portion of this map whose keys are strictly less thantoKey
. 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)
.- Specified by:
headMap
in interfaceConcurrentNavigableMap<K,V>
- Specified by:
headMap
in interfaceNavigableMap<K,V>
- Specified by:
headMap
in interfaceSortedMap<K,V>
- Parameters:
toKey
- high endpoint (exclusive) of the keys in the returned map- Returns:
- a view of the portion of this map whose keys are strictly
less than
toKey
- Throws:
ClassCastException
- iftoKey
is not compatible with this map's comparator (or, if the map has no comparator, iftoKey
does not implementComparable
). Implementations may, but are not required to, throw this exception iftoKey
cannot be compared to keys currently in the map.NullPointerException
- iftoKey
is nullIllegalArgumentException
- if this map itself has a restricted range, andtoKey
lies outside the bounds of the range
-
tailMap
public ConcurrentNavigableMap<K,V> tailMap(K fromKey)
Description copied from interface:NavigableMap
Returns a view of the portion of this map whose keys are greater than or equal tofromKey
. 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)
.- Specified by:
tailMap
in interfaceConcurrentNavigableMap<K,V>
- Specified by:
tailMap
in interfaceNavigableMap<K,V>
- Specified by:
tailMap
in interfaceSortedMap<K,V>
- Parameters:
fromKey
- low endpoint (inclusive) of the keys in the returned map- Returns:
- a view of the portion of this map whose keys are greater
than or equal to
fromKey
- Throws:
ClassCastException
- iffromKey
is not compatible with this map's comparator (or, if the map has no comparator, iffromKey
does not implementComparable
). Implementations may, but are not required to, throw this exception iffromKey
cannot be compared to keys currently in the map.NullPointerException
- iffromKey
is nullIllegalArgumentException
- if this map itself has a restricted range, andfromKey
lies outside the bounds of the range
-
lowerEntry
public Map.Entry<K,V> lowerEntry(K key)
Returns a key-value mapping associated with the greatest key strictly less than the given key, or null if there is no such key. The returned entry does not support the Entry.setValue method.- Specified by:
lowerEntry
in interfaceNavigableMap<K,V>
- Parameters:
key
- the key- Returns:
- an entry with the greatest key less than
key
, ornull
if there is no such key - Throws:
ClassCastException
- if the specified key cannot be compared with the keys currently in the mapNullPointerException
- if the specified key is null
-
lowerKey
public K lowerKey(K key)
Description copied from interface:NavigableMap
Returns the greatest key strictly less than the given key, ornull
if there is no such key.- Specified by:
lowerKey
in interfaceNavigableMap<K,V>
- Parameters:
key
- the key- Returns:
- the greatest key less than
key
, ornull
if there is no such key - Throws:
ClassCastException
- if the specified key cannot be compared with the keys currently in the mapNullPointerException
- if the specified key is null
-
floorEntry
public Map.Entry<K,V> floorEntry(K key)
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. The returned entry does not support the Entry.setValue method.- Specified by:
floorEntry
in interfaceNavigableMap<K,V>
- Parameters:
key
- the key- Returns:
- an entry with the greatest key less than or equal to
key
, ornull
if there is no such key - Throws:
ClassCastException
- if the specified key cannot be compared with the keys currently in the mapNullPointerException
- if the specified key is null
-
floorKey
public K floorKey(K key)
Description copied from interface:NavigableMap
Returns the greatest key less than or equal to the given key, ornull
if there is no such key.- Specified by:
floorKey
in interfaceNavigableMap<K,V>
- Parameters:
key
- the key- Returns:
- the greatest key less than or equal to
key
, ornull
if there is no such key - Throws:
ClassCastException
- if the specified key cannot be compared with the keys currently in the mapNullPointerException
- if the specified key is null
-
ceilingEntry
public Map.Entry<K,V> ceilingEntry(K key)
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 entry. The returned entry does not support the Entry.setValue method.- Specified by:
ceilingEntry
in interfaceNavigableMap<K,V>
- Parameters:
key
- the key- Returns:
- an entry with the least key greater than or equal to
key
, ornull
if there is no such key - Throws:
ClassCastException
- if the specified key cannot be compared with the keys currently in the mapNullPointerException
- if the specified key is null
-
ceilingKey
public K ceilingKey(K key)
Description copied from interface:NavigableMap
Returns the least key greater than or equal to the given key, ornull
if there is no such key.- Specified by:
ceilingKey
in interfaceNavigableMap<K,V>
- Parameters:
key
- the key- Returns:
- the least key greater than or equal to
key
, ornull
if there is no such key - Throws:
ClassCastException
- if the specified key cannot be compared with the keys currently in the mapNullPointerException
- if the specified key is null
-
higherEntry
public Map.Entry<K,V> higherEntry(K key)
Returns a key-value mapping associated with the least key strictly greater than the given key, or null if there is no such key. The returned entry does not support the Entry.setValue method.- Specified by:
higherEntry
in interfaceNavigableMap<K,V>
- Parameters:
key
- the key- Returns:
- an entry with the least key greater than
key
, ornull
if there is no such key - Throws:
ClassCastException
- if the specified key cannot be compared with the keys currently in the mapNullPointerException
- if the specified key is null
-
higherKey
public K higherKey(K key)
Description copied from interface:NavigableMap
Returns the least key strictly greater than the given key, ornull
if there is no such key.- Specified by:
higherKey
in interfaceNavigableMap<K,V>
- Parameters:
key
- the key- Returns:
- the least key greater than
key
, ornull
if there is no such key - Throws:
ClassCastException
- if the specified key cannot be compared with the keys currently in the mapNullPointerException
- if the specified key is null
-
firstEntry
public Map.Entry<K,V> firstEntry()
Returns a key-value mapping associated with the least key in this map, or null if the map is empty. The returned entry does not support the Entry.setValue method.- Specified by:
firstEntry
in interfaceNavigableMap<K,V>
- Returns:
- an entry with the least key,
or
null
if this map is empty
-
lastEntry
public Map.Entry<K,V> lastEntry()
Returns a key-value mapping associated with the greatest key in this map, or null if the map is empty. The returned entry does not support the Entry.setValue method.- Specified by:
lastEntry
in interfaceNavigableMap<K,V>
- Returns:
- an entry with the greatest key,
or
null
if this map is empty
-
pollFirstEntry
public Map.Entry<K,V> pollFirstEntry()
Removes and returns a key-value mapping associated with the least key in this map, or null if the map is empty. The returned entry does not support the Entry.setValue method.- Specified by:
pollFirstEntry
in interfaceNavigableMap<K,V>
- Returns:
- the removed first entry of this map,
or
null
if this map is empty
-
pollLastEntry
public Map.Entry<K,V> pollLastEntry()
Removes and returns a key-value mapping associated with the greatest key in this map, or null if the map is empty. The returned entry does not support the Entry.setValue method.- Specified by:
pollLastEntry
in interfaceNavigableMap<K,V>
- Returns:
- the removed last entry of this map,
or
null
if this map is empty
-
-
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