# ListQueue<E> class Null safety

List based Queue.

Keeps a cyclic buffer of elements, and grows to a larger buffer when it fills up. This guarantees constant time peek and remove operations, and amortized constant time add operations.

The structure is efficient for any queue or stack usage.

Example:

``````final queue = ListQueue<int>();
``````

To add objects to a queue, use add, addAll, addFirst oraddLast.

``````queue.add(5);
queue.addFirst(0);
queue.addLast(10);
queue.addAll([1, 2, 3]);
print(queue); // {0, 5, 10, 1, 2, 3}
``````

To check if the queue is empty, use isEmpty or isNotEmpty. To find the number of queue entries, use length.

``````final isEmpty = queue.isEmpty; // false
final queueSize = queue.length; // 6
``````

To get first or last item from queue, use first or last.

``````final first = queue.first; // 0
final last = queue.last; // 3
``````

To get item value using index, use elementAt.

``````final itemAt = queue.elementAt(2); // 10
``````

To convert queue to list, call toList.

``````final numbers = queue.toList();
print(numbers); // [0, 5, 10, 1, 2, 3]
``````

To remove item from queue, call remove, removeFirst or removeLast.

``````queue.remove(10);
queue.removeFirst();
queue.removeLast();
print(queue); // {5, 1, 2}
``````

To remove multiple elements at the same time, use removeWhere.

``````queue.removeWhere((element) => element == 1);
print(queue); // {5, 2}
``````

To remove all elements in this queue that do not meet a condition, use retainWhere.

``````queue.retainWhere((element) => element < 4);
print(queue); // {2}
``````

To remove all items and empty the set, use clear.

``````queue.clear();
print(queue.isEmpty); // true
print(queue); // {}
``````
Inheritance
Implemented types
Available Extensions

## Constructors

ListQueue([int? initialCapacity])
Create an empty queue.
ListQueue.from(Iterable elements)
Create a `ListQueue` containing all `elements`.
factory
ListQueue.of(Iterable<E> elements)
Create a `ListQueue` from `elements`.
factory

## Properties

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

## Methods

add(E value) → void
Adds `value` at the end of the queue.
override
addAll(Iterable<E> elements) → void
Adds all elements of `iterable` at the end of the queue. The length of the queue is extended by the length of `iterable`.
override
addFirst(E value) → void
Adds `value` at the beginning of the queue.
override
addLast(E value) → void
Adds `value` at the end of the queue.
override
any(bool test(E element)) bool
Checks whether any element of this iterable satisfies `test`.
inherited
cast<R>() Queue<R>
Provides a view of this iterable as an iterable of `R` instances.
override
Removes all elements in the queue. The size of the queue becomes zero.
override
contains( element) bool
Whether the collection contains an element equal to `element`.
inherited
elementAt(int index) → E
Returns the `index`th element.
every(bool test(E element)) bool
Checks whether every element of this iterable satisfies `test`.
inherited
expand<T>(Iterable<T> toElements(E element)) Iterable<T>
Expands each element of this Iterable into zero or more elements.
inherited
firstWhere(bool test(E element), {E orElse()?}) → E
Returns the first element that satisfies the given predicate `test`.
inherited
fold<T>(T initialValue, T combine(T previousValue, E element)) → T
Reduces a collection to a single value by iteratively combining each element of the collection with an existing value
inherited
followedBy(Iterable<E> other) Iterable<E>
Returns the lazy concatenation of this iterable and `other`.
inherited
forEach(void f(E element)) → void
Invokes `action` on each element of this iterable in iteration order.
join([String separator = ""])
Converts each element to a String and concatenates the strings.
inherited
lastWhere(bool test(E element), {E orElse()?}) → E
Returns the last element that satisfies the given predicate `test`.
inherited
map<T>(T toElement(E element)) 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(E combine(E value, E element)) → E
Reduces a collection to a single value by iteratively combining elements of the collection using the provided function.
inherited
remove( value) bool
Removes a single instance of `value` from the queue.
override
removeFirst() → E
Removes and returns the first element of this queue.
override
removeLast() → E
Removes and returns the last element of the queue.
override
removeWhere(bool test(E element)) → void
Remove all elements matched by `test`.
override
retainWhere(bool test(E element)) → void
Remove all elements not matched by `test`.
override
singleWhere(bool test(E element), {E orElse()?}) → E
Returns the single element that satisfies `test`.
inherited
skip(int count) Iterable<E>
Returns an Iterable that provides all but the first `count` elements.
inherited
skipWhile(bool test(E element)) Iterable<E>
Returns an `Iterable` that skips leading elements while `test` is satisfied.
inherited
take(int count) Iterable<E>
Returns a lazy iterable of the `count` first elements of this iterable.
inherited
takeWhile(bool test(E element)) Iterable<E>
Returns a lazy iterable of the leading elements satisfying `test`.
inherited
toList({bool growable = true}) List<E>
Creates a List containing the elements of this Iterable.
toSet() Set<E>
Creates a Set containing the same elements as this iterable.
inherited
toString()
Returns a string representation of (some of) the elements of `this`.
override
where(bool test(E element)) Iterable<E>
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