A Queue is a collection that can be manipulated at both ends. One can iterate over the elements of a queue through forEach or with an Iterator.
It is generally not allowed to modify the queue (add or remove entries)
while an operation in the queue is being performed, for example during a
call to forEach.
Modifying the queue while it is being iterated will most likely break the
iteration.
This goes both for using the iterator directly, or for iterating an
Iterable
returned by a method like map or where.
Example:
final queue = Queue<int>(); // ListQueue() by default
print(queue.runtimeType); // ListQueue
// Adding items to queue
queue.addAll([1, 2, 3]);
queue.addFirst(0);
queue.addLast(10);
print(queue); // {0, 1, 2, 3, 10}
// Removing items from queue
queue.removeFirst();
queue.removeLast();
print(queue); // {1, 2, 3}
- Implemented types
-
- Iterable<
E>
- Iterable<
- Implementers
- Available extensions
Constructors
- Queue()
-
Creates a queue.
factory
- Queue.from(Iterable elements)
-
Creates a queue containing all
elements
.factory -
Queue.of(Iterable<
E> elements) -
Creates a queue from
elements
.factory
Properties
- first → E
-
The first element.
no setterinherited
- firstOrNull → T?
-
Available on Iterable<
The first element of this iterator, orT> , provided by the IterableExtensions extensionnull
if the iterable is empty.no setter - hashCode → int
-
The hash code for this object.
no setterinherited
-
indexed
→ Iterable<
(int, T)> -
Available on Iterable<
Pairs of elements of the indices and elements of this iterable.T> , provided by the IterableExtensions extensionno setter - isEmpty → bool
-
Whether this collection has no elements.
no setterinherited
- isNotEmpty → bool
-
Whether this collection has at least one element.
no setterinherited
-
iterator
→ Iterator<
E> -
A new
Iterator
that allows iterating the elements of thisIterable
.no setterinherited - last → E
-
The last element.
no setterinherited
- lastOrNull → T?
-
Available on Iterable<
The last element of this iterable, orT> , provided by the IterableExtensions extensionnull
if the iterable is empty.no setter - length → int
-
The number of elements in this Iterable.
no setterinherited
-
nonNulls
→ Iterable<
T> -
Available on Iterable<
The non-T?> , provided by the NullableIterableExtensions extensionnull
elements of this iterable.no setter - runtimeType → Type
-
A representation of the runtime type of the object.
no setterinherited
- single → E
-
Checks that this iterable has only one element, and returns that element.
no setterinherited
- singleOrNull → T?
-
Available on Iterable<
The single element of this iterator, orT> , provided by the IterableExtensions extensionnull
.no setter -
wait
→ Future<
List< T> > -
Available on Iterable<
Waits for futures in parallel.Future< , provided by the FutureIterable extensionT> >no setter
Methods
-
add(
E value) → void -
Adds
value
at the end of the queue. -
addAll(
Iterable< E> iterable) → void -
Adds all elements of
iterable
at the end of the queue. The length of the queue is extended by the length ofiterable
. -
addFirst(
E value) → void -
Adds
value
at the beginning of the queue. -
addLast(
E value) → void -
Adds
value
at the end of the queue. -
any(
bool test(E element)) → bool -
Checks whether any element of this iterable satisfies
test
.inherited -
asNameMap(
) → Map< String, T> -
Available on Iterable<
Creates a map from the names of enum values to the values.T> , provided by the EnumByName extension -
byName(
String name) → T -
Available on Iterable<
Finds the enum value in this list with nameT> , provided by the EnumByName extensionname
. -
cast<
R> () → Queue< R> -
Provides a view of this queue as a queue of
R
instances, if necessary.override -
clear(
) → void - Removes all elements in the queue. The size of the queue becomes zero.
-
contains(
Object? element) → bool -
Whether the collection contains an element equal to
element
.inherited -
elementAt(
int index) → E -
Returns the
index
th element.inherited -
elementAtOrNull(
int index) → T? -
Available on Iterable<
The element at positionT> , provided by the IterableExtensions extensionindex
of this iterable, ornull
. -
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 -
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> -
Creates the lazy concatenation of this iterable and
other
.inherited -
forEach(
void action(E 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(E element), {E orElse()?}) → E -
The last element that satisfies the given predicate
test
.inherited -
map<
T> (T toElement(E e)) → Iterable< T> -
The current elements of this iterable modified by
toElement
.inherited -
noSuchMethod(
Invocation invocation) → dynamic -
Invoked when a nonexistent 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(
Object? value) → bool -
Removes a single instance of
value
from the queue. -
removeFirst(
) → E - Removes and returns the first element of this queue.
-
removeLast(
) → E - Removes and returns the last element of the queue.
-
removeWhere(
bool test(E element)) → void -
Removes all elements matched by
test
from the queue. -
retainWhere(
bool test(E element)) → void -
Removes all elements not matched by
test
from the queue. -
singleWhere(
bool test(E element), {E orElse()?}) → E -
The single element that satisfies
test
.inherited -
skip(
int count) → Iterable< E> -
Creates an Iterable that provides all but the first
count
elements.inherited -
skipWhile(
bool test(E value)) → Iterable< E> -
Creates an
Iterable
that skips leading elements whiletest
is satisfied.inherited -
take(
int count) → Iterable< E> -
Creates a lazy iterable of the
count
first elements of this iterable.inherited -
takeWhile(
bool test(E value)) → Iterable< E> -
Creates 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.
inherited
-
toSet(
) → Set< E> -
Creates a Set containing the same elements as this iterable.
inherited
-
toString(
) → String -
A string representation of this object.
inherited
-
where(
bool test(E element)) → Iterable< E> -
Creates a new lazy Iterable with all elements that satisfy the
predicate
test
.inherited -
whereType<
T> () → Iterable< T> -
Creates a new lazy Iterable with all elements that have type
T
.inherited
Operators
-
operator ==(
Object other) → bool -
The equality operator.
inherited