CanonicalizedMap<C, K, V> class

A map whose keys are converted to canonical values of type C.

This is useful for using case-insensitive String keys, for example. It's more efficient than a LinkedHashMap with a custom equality operator because it only canonicalizes each key once, rather than doing so for each comparison.

Implemented types

• Map<K, V>

Available extensions

• MapExt
• NullableMapExt

Constructors

CanonicalizedMap(C canonicalize(K key), {bool isValidKey(K key)?})

Creates an empty canonicalized map.

CanonicalizedMap.from(Map<K, V> other, C canonicalize(K key), {bool isValidKey(K key)?})

Creates a canonicalized map that is initialized with the key/value pairs of other.

CanonicalizedMap.fromEntries(Iterable<MapEntry<K, V>> entries, C canonicalize(K key), {bool isValidKey(K key)?})

Creates a canonicalized map that is initialized with the key/value pairs of entries.

Properties

entries → Iterable<MapEntry<K, V>>

The map entries of this Map.

no setter, override

hashCode → int

The hash code for this object.

no setter, inherited

isEmpty → bool

Whether there is no key/value pair in the map.

no setter, override

isNotEmpty → bool

Whether there is at least one key/value pair in the map.

no setter, override

isNullOrEmpty → bool

Available on Map<K, V>?, provided by the NullableMapExt extension

no setter

keys → Iterable<K>

The keys of this Map.

no setter, override

length → int

The number of key/value pairs in the map.

no setter, override

notNullOrEmpty → bool

Available on Map<K, V>?, provided by the NullableMapExt extension

no setter

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

values → Iterable<V>

The values of this Map.

no setter, override

Methods

addAll(Map<K, V> other) → void

Adds all key/value pairs of other to this map.

override

addEntries(Iterable<MapEntry<K, V>> entries) → void

Adds all key/value pairs of newEntries to this map.

override

cast<K2, V2>() → Map<K2, V2>

Provides a view of this map as having RK keys and RV instances, if necessary.

override

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

copy() → CanonicalizedMap<C, K, V>

Copies this CanonicalizedMap instance without recalculating the canonical values of the keys.

equals(Map<K, V> other) → bool

Available on Map<K, V>, provided by the MapExt extension

forEach(void f(K, V)) → void

Applies action to each key/value pair of the map.

override

map<K2, V2>(MapEntry<K2, V2> transform(K, V)) → Map<K2, V2>

Returns a new map where all entries of this map are transformed by the given convert function.

override

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

put(K key, V value) → void

Available on Map<K, V>, provided by the MapExt extension

putIfAbsent(K key, V ifAbsent()) → V

Look up the value of key, or add a new entry if it isn't there.

override

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.

override

retype<K2, V2>() → Map<K2, V2>

sign() → String

Available on Map<K, V>, provided by the MapExt extension

toMap() → Map<K, V>

Creates a Map<K,V> (with the original key values). See toMapOfCanonicalKeys.

toMapOfCanonicalKeys() → Map<C, V>

Creates a Map<C,V> (with the canonicalized keys). See toMap.

toString() → String

A string representation of this object.

override

update(K key, V update(V), {V ifAbsent()?}) → V

Updates the value for the provided key.

override

updateAll(V update(K key, V value)) → void

Updates all values.

override

where(bool test(K key, V value)) → Map<K, V>

Available on Map<K, V>, provided by the MapExt extension

whereKey(bool test(K key)) → Map<K, V>

Available on Map<K, V>, provided by the MapExt extension

whereValue(bool test(V value)) → Map<K, V>

Available on Map<K, V>, provided by the MapExt extension

Operators

operator +(Map<K, V> other) → Map<K, V>

Available on Map<K, V>, provided by the MapExt extension

合并两个Map, 如果有相同的key, other中的key-value会被保留

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