WeakHashMap<K extends Object, V> class

An unordered hash-table based Map implementation with weak referenced keys. An entry in this weak hash map will be automatically removed when its key is garbage collected. That is, when there is no other way for the program to access the weak referenced key, its associated entry in this WeakHashMap is likely removed anytime.

Note that the key object of type K must be a type that can be applied into WeakReference target. i.e. K must NOT be numbers, strings, booleans, records, null, dart:ffi pointers, dart:ffi structs, or dart:ffi unions.

Besides the weak referenced keys, the attributes of this WeakHashMap is the same to regular HashMap.

Mixed-in types

Constructors

WeakHashMap.new({bool equals(K, K)?, int hashCode(K)?, bool isValidKey(dynamic)?, int initCapacity = _defaultCapacity, double loadFactor = _defaultLoadFactor})
Create an unordered hash-table based Map with weak referenced keys.
WeakHashMap.from(Map other)
Create a WeakHashMap per the provided other map. The other's keys must be K type while values must be V type. However, the other map itself can have any type.
factory
WeakHashMap.fromEntries(Iterable<MapEntry<K, V>> entries)
Create a WeakHashMap containing the provided entries. If multiple entries have the same key and value, the 1st entry is preserved. If multiple entries have the same key, the 1st key is preserved and value overwritten.
factory
WeakHashMap.fromIterable(Iterable iterable, {K key(dynamic element)?, V value(dynamic element)?})
Creates a WeakHashMap where the keys and values are computed from the iterable elements.
factory
WeakHashMap.fromIterables(Iterable<K> keys, Iterable<V> values)
Creates a WeakHashMap per the provided keys and values iterables. It is an error if keys and values do not have the same length.
factory
WeakHashMap.identity()
Create an unordered identity-based map. Keys in this map are considered equal only if they are the same object.
factory
WeakHashMap.of(Map<K, V> other)
Create a WeakHashMap per the provided other map of the same K type keys and V type values.
factory

Properties

entries → Iterable<MapEntry<K, V>>
The map entries of this Map.
no setteroverride
hashCode → int
The hash code for this object.
no setterinherited
isEmpty → bool
Whether there is no key/value pair in the map.
no setteroverride
isNotEmpty → bool
Whether there is at least one key/value pair in the map.
no setteroverride
keys → Iterable<K>
The keys of this Map.
no setteroverride
length → int
The number of key/value pairs in the map.
no setteroverride
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
values → Iterable<V>
The values of this Map.
no setteroverride

Methods

addAll(Map<K, V> other) → void
Adds all key/value pairs of other to this map.
override
addEntries(Iterable<MapEntry<K, V>> newEntries) → void
Adds all key/value pairs of newEntries to this map.
override
cast<RK, RV>() → Map<RK, RV>
Provides a view of this map as having RK keys and RV instances, if necessary.
inherited
clear() → void
Removes all entries from the map.
override
containsKey(Object? key) → bool
Whether this map contains the given key.
override
containsValue(Object? value) → bool
Whether this map contains the given value.
override
forEach(void action(K key, V value)) → void
Applies action to each key/value pair of the map.
inherited
map<K2, V2>(MapEntry<K2, V2> transform(K key, V value)) → Map<K2, V2>
Returns a new map where all entries of this map are transformed by the given convert function.
inherited
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
putIfAbsent(K key, V ifAbsent()) → V
Look up the value of key, or add a new entry if it isn't there.
inherited
remove(Object? key) → V?
Removes key and its associated value, if present, from the map.
override
removeWhere(bool test(K key, V value)) → void
Removes all entries of this map that satisfy the given test.
inherited
toString() → String
A string representation of this object.
inherited
update(K key, V update(V value), {V ifAbsent()?}) → V
Updates the value for the provided key.
inherited
updateAll(V update(K key, V value)) → void
Updates all values.
inherited

Operators

operator ==(Object other) → bool
The equality operator.
inherited
operator [](Object? key) → V?
The value for the given key, or null if key is not in the map.
override
operator []=(K key, V value) → void
Associates the key with the given value.
override