K - the type of keys maintained by this mapV - the type of mapped valuespublic class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V> implements ConcurrentNavigableMap<K,V>, Cloneable, Serializable
A scalable concurrent ConcurrentNavigableMap 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 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 and spliterators are weakly consistent.
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 and Iterator 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.
AbstractMap.SimpleEntry<K,V>, AbstractMap.SimpleImmutableEntry<K,V> Map.Entry<K,V> public ConcurrentSkipListMap()
Constructs a new, empty map, sorted according to the natural ordering of the keys.
public ConcurrentSkipListMap(Comparator<? super K> comparator)
Constructs a new, empty map, sorted according to the specified comparator.
comparator - the comparator that will be used to order this map. If null, the natural ordering of the keys will be used.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.
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 or any of its keys or values are nullpublic ConcurrentSkipListMap(SortedMap<K,? extends V> m)
Constructs a new map containing the same mappings and using the same ordering as the specified sorted map.
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 sorted map or any of its keys or values are nullpublic ConcurrentSkipListMap<K,V> clone()
Returns a shallow copy of this ConcurrentSkipListMap instance. (The keys and values themselves are not cloned.)
clone in class AbstractMap<K,V>
Cloneablepublic boolean containsKey(Object key)
Returns 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 nullpublic V get(Object key)
Returns the value to which the specified key is mapped, or 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.)
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 nullpublic V getOrDefault(Object key,
V defaultValue) Returns the value to which the specified key is mapped, or the given defaultValue if this map contains no mapping for the key.
getOrDefault in interface ConcurrentMap<K,V>
getOrDefault in interface Map<K,V>
key - the keydefaultValue - the value to return if this map contains no mapping for the given keyNullPointerException - if the specified key is nullpublic 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.
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 keynull if there was no mapping for the keyClassCastException - if the specified key cannot be compared with the keys currently in the mapNullPointerException - if the specified key or value is nullpublic V remove(Object key)
Removes the mapping for the specified key from this map if present.
remove in interface Map<K,V>
remove in class AbstractMap<K,V>
key - key for which mapping should be removednull if there was no mapping for the keyClassCastException - if the specified key cannot be compared with the keys currently in the mapNullPointerException - if the specified key is nullpublic 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.
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 otherwiseNullPointerException - if the specified value is nullpublic 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.
size in interface Map<K,V>
size in class AbstractMap<K,V>
public boolean isEmpty()
Returns true if this map contains no key-value mappings.
isEmpty in interface Map<K,V>
isEmpty in class AbstractMap<K,V>
true if this map contains no key-value mappingspublic void clear()
Removes all of the mappings from this map.
public V computeIfAbsent(K key,
Function<? super K,? extends V> mappingFunction) If the specified key is not already associated with a value, attempts to compute its value using the given mapping function and enters it into this map unless null. The function is NOT guaranteed to be applied once atomically only if the value is not present.
computeIfAbsent in interface ConcurrentMap<K,V>
computeIfAbsent in interface Map<K,V>
key - key with which the specified value is to be associatedmappingFunction - the function to compute a valueNullPointerException - if the specified key is null or the mappingFunction is nullpublic V computeIfPresent(K key,
BiFunction<? super K,? super V,? extends V> remappingFunction) If the value for the specified key is present, attempts to compute a new mapping given the key and its current mapped value. The function is NOT guaranteed to be applied once atomically.
computeIfPresent in interface ConcurrentMap<K,V>
computeIfPresent in interface Map<K,V>
key - key with which a value may be associatedremappingFunction - the function to compute a valueNullPointerException - if the specified key is null or the remappingFunction is nullpublic V compute(K key,
BiFunction<? super K,? super V,? extends V> remappingFunction) Attempts to compute a mapping for the specified key and its current mapped value (or null if there is no current mapping). The function is NOT guaranteed to be applied once atomically.
compute in interface ConcurrentMap<K,V>
compute in interface Map<K,V>
key - key with which the specified value is to be associatedremappingFunction - the function to compute a valueNullPointerException - if the specified key is null or the remappingFunction is nullpublic V merge(K key,
V value,
BiFunction<? super V,? super V,? extends V> remappingFunction) If the specified key is not already associated with a value, associates it with the given value. Otherwise, replaces the value with the results of the given remapping function, or removes if null. The function is NOT guaranteed to be applied once atomically.
merge in interface ConcurrentMap<K,V>
merge in interface Map<K,V>
key - key with which the specified value is to be associatedvalue - the value to use if absentremappingFunction - the function to recompute a value if presentNullPointerException - if the specified key or value is null or the remappingFunction is nullpublic NavigableSet<K> keySet()
Returns a NavigableSet view of the keys contained in this map.
The set's iterator returns the keys in ascending order. The set's spliterator additionally reports Spliterator.CONCURRENT, Spliterator.NONNULL, 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 map's comparator (see comparator()) is null. Otherwise, the spliterator's comparator is the same as or imposes the same total ordering as the map's comparator.
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 iterators and spliterators are weakly consistent.
This method is equivalent to method navigableKeySet.
keySet in interface ConcurrentNavigableMap<K,V>
keySet in interface Map<K,V>
keySet in interface SortedMap<K,V>
keySet in class AbstractMap<K,V>
public NavigableSet<K> navigableKeySet()
Description copied from interface: ConcurrentNavigableMap
Returns a NavigableSet 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 the Iterator.remove, Set.remove, removeAll, retainAll, and clear operations. It does not support the add or addAll operations.
The view's iterators and spliterators are weakly consistent.
navigableKeySet in interface ConcurrentNavigableMap<K,V>
navigableKeySet in interface NavigableMap<K,V>
public Collection<V> values()
Returns a Collection view of the values contained in this map.
The collection's iterator returns the values in ascending order of the corresponding keys. The collections's spliterator additionally reports Spliterator.CONCURRENT, Spliterator.NONNULL and 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. 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 iterators and spliterators are weakly consistent.
values in interface Map<K,V>
values in interface SortedMap<K,V>
values in class AbstractMap<K,V>
public Set<Map.Entry<K,V>> entrySet()
Returns a Set view of the mappings contained in this map.
The set's iterator returns the entries in ascending key order. The set's spliterator additionally reports Spliterator.CONCURRENT, Spliterator.NONNULL, 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. 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 iterators and spliterators are weakly consistent.
The Map.Entry elements traversed by the iterator or spliterator do not support the setValue operation.
entrySet in interface Map<K,V>
entrySet in interface SortedMap<K,V>
entrySet in class AbstractMap<K,V>
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 expression m.descendingMap().descendingMap() returns a view of m essentially equivalent to m.
descendingMap in interface ConcurrentNavigableMap<K,V>
descendingMap in interface NavigableMap<K,V>
public NavigableSet<K> descendingKeySet()
Description copied from interface: ConcurrentNavigableMap
Returns a reverse order 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. 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 iterators and spliterators are weakly consistent.
descendingKeySet in interface ConcurrentNavigableMap<K,V>
descendingKeySet in interface NavigableMap<K,V>
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.
equals in interface Map<K,V>
equals in class AbstractMap<K,V>
o - object to be compared for equality with this maptrue if the specified object is equal to this mapObject.hashCode(), HashMap
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 to
if (!map.containsKey(key)) return map.put(key, value); else return map.get(key);except that the action is performed atomically.
putIfAbsent in interface ConcurrentMap<K,V>
putIfAbsent in interface Map<K,V>
key - key with which the specified value is to be associatedvalue - value to be associated with the specified keynull if there was no mapping for the keyClassCastException - if the specified key cannot be compared with the keys currently in the mapNullPointerException - if the specified key or value is nullpublic boolean remove(Object key,
Object value) Removes the entry for a key only if currently mapped to a given value. This is equivalent to
if (map.containsKey(key) && Objects.equals(map.get(key), value)) {
map.remove(key);
return true;
} else
return false; except that the action is performed atomically. remove in interface ConcurrentMap<K,V>
remove in interface Map<K,V>
key - key with which the specified value is associatedvalue - value expected to be associated with the specified keytrue if the value was removedClassCastException - if the specified key cannot be compared with the keys currently in the mapNullPointerException - if the specified key is nullpublic 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 to
if (map.containsKey(key) && Objects.equals(map.get(key), oldValue)) {
map.put(key, newValue);
return true;
} else
return false; except that the action is performed atomically. replace in interface ConcurrentMap<K,V>
replace in interface Map<K,V>
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 keytrue if the value was replacedClassCastException - if the specified key cannot be compared with the keys currently in the mapNullPointerException - if any of the arguments are nullpublic V replace(K key,
V value) Replaces the entry for a key only if currently mapped to some value. This is equivalent to
if (map.containsKey(key)) {
return map.put(key, value);
} else
return null; except that the action is performed atomically. replace in interface ConcurrentMap<K,V>
replace in interface Map<K,V>
key - key with which the specified value is associatedvalue - value to be associated with the specified keynull if there was no mapping for the keyClassCastException - if the specified key cannot be compared with the keys currently in the mapNullPointerException - if the specified key or value is nullpublic Comparator<? super K> comparator()
Description copied from interface: SortedMap
Returns the comparator used to order the keys in this map, or 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()
Description copied from interface: SortedMap
Returns the first (lowest) key currently in this map.
firstKey in interface SortedMap<K,V>
NoSuchElementException - if this map is emptypublic K lastKey()
Description copied from interface: SortedMap
Returns the last (highest) key currently in this map.
lastKey in interface SortedMap<K,V>
NoSuchElementException - if this map is emptypublic 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 from 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 ConcurrentNavigableMap<K,V>
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 nullIllegalArgumentException - 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 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, if 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 ConcurrentNavigableMap<K,V>
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 nullIllegalArgumentException - if this map itself has a restricted range, and toKey lies outside the bounds of the rangepublic 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, if 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 ConcurrentNavigableMap<K,V>
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 nullIllegalArgumentException - if this map itself has a restricted range, and fromKey lies outside the bounds of the rangepublic 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 from 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 ConcurrentNavigableMap<K,V>
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 nullIllegalArgumentException - 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 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 than 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 ConcurrentNavigableMap<K,V>
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 nullIllegalArgumentException - if this map itself has a restricted range, and toKey lies outside the bounds of the rangepublic 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 to 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 ConcurrentNavigableMap<K,V>
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 nullIllegalArgumentException - if this map itself has a restricted range, and fromKey lies outside the bounds of the rangepublic 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.
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 nullpublic K lowerKey(K key)
Description copied from interface: NavigableMap
Returns the greatest key strictly less than the given key, or 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 nullpublic 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.
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 nullpublic K floorKey(K key)
Description copied from interface: NavigableMap
Returns the greatest key less than or equal to the given key, or 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 nullpublic 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.
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 nullpublic K ceilingKey(K key)
Description copied from interface: NavigableMap
Returns the least key greater than or equal to the given key, or 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 nullpublic 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.
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 nullpublic K higherKey(K key)
Description copied from interface: NavigableMap
Returns the least key strictly greater than the given key, or 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 nullpublic 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.
firstEntry in interface NavigableMap<K,V>
null if this map is emptypublic 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.
lastEntry in interface NavigableMap<K,V>
null if this map is emptypublic 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.
pollFirstEntry in interface NavigableMap<K,V>
null if this map is emptypublic 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.
pollLastEntry in interface NavigableMap<K,V>
null if this map is emptypublic void forEach(BiConsumer<? super K,? super V> action)
Description copied from interface: ConcurrentMap
Performs the given action for each entry in this map until all entries have been processed or the action throws an exception. Unless otherwise specified by the implementing class, actions are performed in the order of entry set iteration (if an iteration order is specified.) Exceptions thrown by the action are relayed to the caller.
forEach in interface ConcurrentMap<K,V>
forEach in interface Map<K,V>
action - The action to be performed for each entrypublic void replaceAll(BiFunction<? super K,? super V,? extends V> function)
Description copied from interface: ConcurrentMap
Replaces each entry's value with the result of invoking the given function on that entry until all entries have been processed or the function throws an exception. Exceptions thrown by the function are relayed to the caller.
replaceAll in interface ConcurrentMap<K,V>
replaceAll in interface Map<K,V>
function - the function to apply to each entry
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