ObserverList<T> class Null safety

A list optimized for the observer pattern when there are small numbers of observers.

Consider using an ObserverList instead of a List when the number of contains calls dominates the number of add and remove calls.

This class will include in the iterator each added item in the order it was added, as many times as it was added.

If there will be a large number of observers, consider using HashedObserverList instead. It has slightly different iteration semantics, but serves a similar purpose, while being more efficient for large numbers of observers.

See also:

Inheritance
Available Extensions

Constructors

ObserverList()

Properties

first → T
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-onlyoverride
isNotEmpty → bool
Whether this collection has at least one element.
read-onlyoverride
iterator → Iterator<T>
Returns a new Iterator that allows iterating the elements of this Iterable.
read-onlyoverride
last → T
Returns the last element.
read-onlyinherited
length → int
Returns the number of elements in this.
read-onlyinherited
runtimeType → Type
A representation of the runtime type of the object.
read-onlyinherited
single → T
Checks that this iterable has only one element, and returns that element.
read-onlyinherited

Methods

add(T item) → void
Adds an item to the end of this list.
any(bool test(T element)) → bool
Checks whether any element of this iterable satisfies test.
inherited
cast<R>() → Iterable<R>
Provides a view of this iterable as an iterable of R instances.
inherited
clear() → void
Removes all items from the list.
contains(Object? element) → bool
Whether the collection contains an element equal to element.
override
elementAt(int index) → T
Returns the indexth element.
inherited
every(bool test(T element)) → bool
Checks whether every element of this iterable satisfies test.
inherited
expand<T>(Iterable<T> toElements(T element)) → Iterable<T>
Expands each element of this Iterable into zero or more elements.
inherited
firstWhere(bool test(T element), {T orElse()?}) → T
Returns the first element that satisfies the given predicate test.
inherited
fold<T>(T initialValue, T combine(T previousValue, T element)) → T
Reduces a collection to a single value by iteratively combining each element of the collection with an existing value
inherited
followedBy(Iterable<T> other) → Iterable<T>
Returns the lazy concatenation of this iterable and other.
inherited
forEach(void action(T element)) → void
Invokes action on each element of this iterable in iteration order.
inherited
join([String separator = ""]) → String
Converts each element to a String and concatenates the strings.
inherited
lastWhere(bool test(T element), {T orElse()?}) → T
Returns the last element that satisfies the given predicate test.
inherited
map<T>(T toElement(T e)) → 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(T combine(T value, T element)) → T
Reduces a collection to a single value by iteratively combining elements of the collection using the provided function.
inherited
remove(T item) → bool
Removes an item from the list.
singleWhere(bool test(T element), {T orElse()?}) → T
Returns the single element that satisfies test.
inherited
skip(int count) → Iterable<T>
Returns an Iterable that provides all but the first count elements.
inherited
skipWhile(bool test(T value)) → Iterable<T>
Returns an Iterable that skips leading elements while test is satisfied.
inherited
take(int count) → Iterable<T>
Returns a lazy iterable of the count first elements of this iterable.
inherited
takeWhile(bool test(T value)) → Iterable<T>
Returns a lazy iterable of the leading elements satisfying test.
inherited
toList({bool growable = true}) → List<T>
Creates a List containing the elements of this Iterable.
override
toSet() → Set<T>
Creates a Set containing the same elements as this iterable.
inherited
toString() → String
Returns a string representation of (some of) the elements of this.
inherited
where(bool test(T element)) → Iterable<T>
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