MapValueSet<K, V> class Null safety

Creates a modifiable Set view of the values of a Map.

The Set view assumes that the keys of the Map can be uniquely determined from the values. The keyForValue function passed to the constructor finds the key for a single value. The keyForValue function should be consistent with equality. If value1 == value2 then keyForValue(value1) and keyForValue(value2) should be considered equal keys by the underlying map, and vice versa.

Modifying the set will modify the underlying map based on the key returned by keyForValue.

If the Map contents are not compatible with the keyForValue function, the set will not work consistently, and may give meaningless responses or do inconsistent updates.

This set can, for example, be used on a map from database record IDs to the records. It exposes the records as a set, and allows for writing both recordSet.add(databaseRecord) and recordMap[id].

Effectively, the map will act as a kind of index for the set.

Implemented types
Available Extensions

Constructors

MapValueSet(Map<K, V> _baseMap, K _keyForValue(V))
Creates a new MapValueSet based on _baseMap.

Properties

first → V
Returns the first element.
read-onlyinherited
hashCode → int
The hash code for this object.
read-onlyinherited
isEmpty → bool
Whether this collection has no elements.
read-only
isNotEmpty → bool
Whether this collection has at least one element.
read-only
iterator → Iterator<V>
Returns a new Iterator that allows iterating the elements of this Iterable.
read-onlyinherited
last → V
Returns the last element.
read-onlyinherited
length → int
Returns the number of elements in this.
read-only
runtimeType → Type
A representation of the runtime type of the object.
read-onlyinherited
single → V
Checks that this iterable has only one element, and returns that element.
read-onlyinherited

Methods

add(V value) → bool
Adds value to the set.
override
addAll(Iterable<V> elements) → void
Adds all elements to this set.
override
any(bool test(V)) → bool
Checks whether any element of this iterable satisfies test.
inherited
cast<T>() → Set<T>
Provides a view of this iterable as an iterable of R instances.
clear() → void
Removes all elements from the set.
override
contains(Object? element) → bool
Whether the collection contains an element equal to element.
containsAll(Iterable<Object?> other) → bool
Whether this set contains all the elements of other.
override
difference(Set<Object?> other) → Set<V>
Returns a new set with the the elements of this that are not in other.
override
elementAt(int index) → V
Returns the indexth element.
inherited
every(bool test(V)) → bool
Checks whether every element of this iterable satisfies test.
inherited
expand<T>(Iterable<T> f(V)) → Iterable<T>
Expands each element of this Iterable into zero or more elements.
inherited
firstWhere(bool test(V), {V orElse()?}) → V
Returns the first element that satisfies the given predicate test.
inherited
fold<T>(T initialValue, T combine(T previousValue, V element)) → T
Reduces a collection to a single value by iteratively combining each element of the collection with an existing value
inherited
followedBy(Iterable<V> other) → Iterable<V>
Returns the lazy concatenation of this iterable and other.
inherited
forEach(void f(V)) → void
Invokes action on each element of this iterable in iteration order.
inherited
intersection(Set<Object?> other) → Set<V>
Returns a new set which is the intersection between this and other.
override
join([String separator = '']) → String
Converts each element to a String and concatenates the strings.
inherited
lastWhere(bool test(V), {V orElse()?}) → V
Returns the last element that satisfies the given predicate test.
inherited
lookup(Object? element) → V?
If an object equal to object is in the set, return it.
override
map<T>(T f(V)) → Iterable<T>
The current elements of this iterable modified by toElement.
inherited
noSuchMethod(Invocation invocation) → dynamic
Invoked when a non-existent method or property is accessed.
inherited
reduce(V combine(V value, V element)) → V
Reduces a collection to a single value by iteratively combining elements of the collection using the provided function.
inherited
remove(Object? element) → bool
Removes value from the set.
override
removeAll(Iterable<Object?> elements) → void
Removes each element of elements from this set.
override
removeWhere(bool test(V)) → void
Removes all elements of this set that satisfy test.
override
retainAll(Iterable<Object?> elements) → void
Removes all elements of this set that are not elements in elements.
override
retainWhere(bool test(V)) → void
Removes all elements of this set that fail to satisfy test.
override
retype<T>() → Set<T>
Deprecated("Use cast instead")">@Deprecated("Use cast instead")
singleWhere(bool test(V), {V orElse()?}) → V
Returns the single element that satisfies test.
inherited
skip(int n) → Iterable<V>
Returns an Iterable that provides all but the first count elements.
inherited
skipWhile(bool test(V)) → Iterable<V>
Returns an Iterable that skips leading elements while test is satisfied.
inherited
take(int n) → Iterable<V>
Returns a lazy iterable of the count first elements of this iterable.
inherited
takeWhile(bool test(V)) → Iterable<V>
Returns a lazy iterable of the leading elements satisfying test.
inherited
toList({bool growable = true}) → List<V>
Creates a List containing the elements of this Iterable.
inherited
toSet() → Set<V>
Creates a Set containing the same elements as this iterable.
inherited
toString() → String
A string representation of this object.
union(Set<V> other) → Set<V>
Returns a new set which contains all the elements of this and other.
override
where(bool test(V)) → Iterable<V>
Returns a new lazy Iterable with all elements that satisfy the predicate test.
inherited
whereType<T>() → Iterable<T>
Returns a new lazy Iterable with all elements that have type T.
inherited

Operators

operator ==(Object other) → bool
The equality operator.
inherited