Queue<E> class

A first-in-first-out (FIFO) queue interface implementation, mimicking Java's Queue.

This implementation provides queue operations using a List as the underlying storage. Elements are added to the rear and removed from the front.

Key Features:

FIFO ordering: First element added is first to be removed
Dynamic sizing: Grows and shrinks as needed
List-based: Built on top of a resizable array
Efficient operations: Optimized for queue use cases

Usage Examples:

final queue = Queue<String>();

// Add elements to the queue
queue.offer('first');
queue.offer('second');
queue.offer('third');

// Peek at the front element
print(queue.peek()); // 'first'

// Remove elements from the queue
print(queue.poll()); // 'first'
print(queue.poll()); // 'second'

// Check size
print(queue.size()); // 1

// Check if empty
print(queue.isEmpty); // false

Inheritance

Object
ListBase<E>
Queue

Available extensions

Annotations

@Generic(Queue)

Constructors

Queue(): Creates an empty Queue.
Queue.from(Iterable<E> iterable): Creates a Queue from an iterable.
Queue.withCapacity(int capacity): Creates a Queue with the specified initial capacity.

Properties

first ↔ E: The first element.
getter/setter pairinherited-setteroverride-getter
firstOrNull → T?: Available on Iterable<T>, provided by the IterableExtensions extension
The first element of this iterator, or null if the iterable is empty.
no setter
hashCode → int: The hash code for this object.
no setterinherited
indexed → Iterable<(int, T)>: Available on Iterable<T>, provided by the IterableExtensions extension
Pairs of elements of the indices and elements of this iterable.
no setter
isEmpty → bool: Whether this collection has no elements.
no setteroverride
isNotEmpty → bool: Whether this collection has at least one element.
no setteroverride
isOneAKind → bool: Available on List<T>, provided by the ListExtensions extension
Checks if all list data have same value.
no setter
iterator → Iterator<E>: A new Iterator that allows iterating the elements of this Iterable.
no setteroverride
last ↔ E: The last element.
getter/setter pairinherited-setteroverride-getter
lastOrNull → T?: Available on Iterable<T>, provided by the IterableExtensions extension
The last element of this iterable, or null if the iterable is empty.
no setter
length ↔ int: The number of objects in this list.
getter/setter pairoverride
nonNulls → Iterable<T>: Available on Iterable<T?>, provided by the NullableIterableExtensions extension
The non-null elements of this iterable.
no setter
reversed → Iterable<E>: An Iterable of the objects in this list in reverse order.
no setterinherited
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 setteroverride
singleOrNull → T?: Available on Iterable<T>, provided by the IterableExtensions extension
The single element of this iterator, or null.
no setter
toJS → JSArray<T>: Available on List<T>, provided by the ListToJSArray extension
Converts this List to a JSArray by either casting, unwrapping, or cloning the List.
no setter
toJSProxyOrRef → JSArray<T>: Available on List<T>, provided by the ListToJSArray extension
Converts this List to a JSArray by either casting, unwrapping, or proxying the List.
no setter
wait → Future<List<T>>: Available on Iterable<Future<T>>, provided by the FutureIterable extension
Waits for futures in parallel.
no setter

Methods

add(E element) → void: Adds value to the end of this list, extending the length by one.
override
addAll(Iterable<E> iterable) → void: Appends all objects of iterable to the end of this list.
override
addAllIf(ConditionTester<T> condition, Iterable<T> items) → void: Available on List<T>, provided by the ListExtensions extension
Adds all items from another list to a list if a condition is met.
addIf(ConditionTester<T> condition, T element) → void: Available on List<T>, provided by the ListExtensions extension
Adds an item to a list if a condition is met.
all(ConditionTester<T> test) → bool: Available on Iterable<T>, provided by the IterableExtension extension
Checks whether all elements of this iterable satisfy test.
any(bool test(E element)) → bool: Checks whether any element of this iterable satisfies test.
inherited
asMap() → Map<int, E>: An unmodifiable Map view of this list.
inherited
asNameMap() → Map<String, T>: Available on Iterable<T>, provided by the EnumByName extension
Creates a map from the names of enum values to the values.
byName(String name) → T: Available on Iterable<T>, provided by the EnumByName extension
Finds the enum value in this list with name name.
cast<R>() → List<R>: Returns a view of this list as a list of R instances.
inherited
clear() → void: Removes all objects from this list; the length of the list becomes zero.
override
clone() → Queue<E>: Creates a copy of this Queue.
contains(Object? element) → bool: Whether the collection contains an element equal to element.
override
element() → E: Retrieves, but does not remove, the head of this queue.
elementAt(int index) → E: Returns the indexth element.
inherited
elementAtOrNull(int index) → T?: Available on Iterable<T>, provided by the IterableExtensions extension
The element at position index of this iterable, or null.
every(bool test(E element)) → bool: Checks whether every element of this iterable satisfies test.
inherited
expand<T>(Iterable<T> f(E element)) → Iterable<T>: Expands each element of this Iterable into zero or more elements.
inherited
fillRange(int start, int end, [E? fill]) → void: Overwrites a range of elements with fillValue.
inherited
filter(ConditionTester<T> test) → Iterable<T>: Available on Iterable<T>, provided by the IterableExtension extension
Filters elements based on a predicate (alias for where).
filterWhere(ConditionTester<T> test) → Iterable<T>: Available on Iterable<T>, provided by the IterableExtension extension
Filters elements based on a predicate.
find(ConditionTester<T> test) → T?: Available on Iterable<T>, provided by the IterableExtension extension
Finds the first element that satisfies the given predicate.
findIndex(ConditionTester<T> test) → int: Available on Iterable<T>, provided by the IterableExtension extension
Finds the index of the first element that satisfies the given predicate.
firstWhere(bool test(E element), {E orElse()?}) → E: The first element that satisfies the given predicate test.
inherited
firstWhereOrNull(ConditionTester<T> test) → T?: Available on Iterable<T>, provided by the IterableExtension extension
Returns the first element that satisfies the predicate or null if none match.
flatMap<E>(Iterable<E> selector(T item)) → Iterable<E>: Available on Iterable<T>, provided by the IterableExtension extension
Flattens lists of items into a single iterable.
flatten<E>(E? selector(T item)) → Iterable<E>: Available on Iterable<T>, provided by the IterableExtension extension
Transforms each element of the iterable into zero or more elements of type E and flattens the results.
flattenIterable<E>(Iterable<E>? selector(T item)) → Iterable<E>: Available on Iterable<T>, provided by the IterableExtension extension
Transforms each element of the iterable into zero or more results of type E, and flattens the resulting collections into a single iterable.
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
get([int index = 0]) → T: Available on Iterable<T>, provided by the IterableExtension extension
Returns the element at the specified index.
getFirst() → T: Available on Iterable<T>, provided by the IterableExtension extension
Returns the first element of the iterable.
getLast() → T: Available on Iterable<T>, provided by the IterableExtension extension
Returns the last element of the iterable.
getRange(int start, int end) → Iterable<E>: Creates an Iterable that iterates over a range of elements.
inherited
group<K>(K keySelector(T item)) → Map<K, List<T>>: Available on Iterable<T>, provided by the IterableExtension extension
Groups the elements of the iterable by a key returned from the keySelector function.
groupBy<K>(K keySelector(T item)) → Map<K, List<T>>: Available on Iterable<T>, provided by the IterableExtension extension
Groups elements of this iterable into a Map using the given keySelector.
groupByAndMap<K, V>(K keySelector(T item), V valueSelector(T item)) → Map<K, List<V>>: Available on Iterable<T>, provided by the IterableExtension extension
Groups elements of this iterable into a Map using keySelector, and applies valueSelector to each element before storing it.
indexOf(Object? element, [int start = 0]) → int: The first index of element in this list.
override
indexWhere(bool test(E element), [int start = 0]) → int: The first index in the list that satisfies the provided test.
inherited
indexWhereOrNull(ConditionTester<T> test) → int?: Available on Iterable<T>, provided by the IterableExtension extension
Finds the index of an element that satisfies the predicate or returns null if not found.
insert(int index, E element) → void: Inserts element at position index in this list.
override
insertAll(int index, Iterable<E> iterable) → void: Inserts all objects of iterable at position index in this list.
inherited
isLengthBetween(int min, int max) → bool: Available on Iterable<T>, provided by the IterableExtension extension
Checks if length of double value is BETWEEN minLength to max.
isLengthEqualTo(int other) → bool: Available on Iterable<T>, provided by the IterableExtension extension
Checks if length of double value is EQUAL to max.
isLengthEt(int max) → bool: Available on Iterable<T>, provided by the IterableExtension extension
Short form for isLengthEqualTo
isLengthGreaterThan(int max) → bool: Available on Iterable<T>, provided by the IterableExtension extension
Checks if length of double value is GREATER than max.
isLengthGreaterThanOrEqualTo(int max) → bool: Available on Iterable<T>, provided by the IterableExtension extension
Checks if length of double value is GREATER OR EQUAL to max.
isLengthGt(int max) → bool: Available on Iterable<T>, provided by the IterableExtension extension
Short form for isLengthGreaterThan
isLengthGtEt(int max) → bool: Available on Iterable<T>, provided by the IterableExtension extension
Short form for isLengthGreaterThanOrEqualTo
isLengthLessThan(int max) → bool: Available on Iterable<T>, provided by the IterableExtension extension
Checks if length of double value is LESS than max.
isLengthLessThanOrEqualTo(int max) → bool: Available on Iterable<T>, provided by the IterableExtension extension
Checks if length of double value is LESS OR EQUAL to max.
isLengthLt(int max) → bool: Available on Iterable<T>, provided by the IterableExtension extension
Short form for isLengthLessThan
isLengthLtEt(int max) → bool: Available on Iterable<T>, provided by the IterableExtension extension
Short form for isLengthLessThanOrEqualTo
join([String separator = ""]) → String: Converts each element to a String and concatenates the strings.
inherited
lastIndexOf(Object? element, [int? start]) → int: The last index of element in this list.
override
lastIndexWhere(bool test(E element), [int? start]) → int: The last index in the list that satisfies the provided test.
inherited
lastWhere(bool test(E element), {E orElse()?}) → E: The last element that satisfies the given predicate test.
inherited
lastWhereOrNull(ConditionTester<T> test) → T?: Available on Iterable<T>, provided by the IterableExtension extension
Returns the last element that satisfies the predicate or null if none match.
map<T>(T f(E element)) → Iterable<T>: The current elements of this iterable modified by toElement.
inherited
none(ConditionTester<T> test) → bool: Available on Iterable<T>, provided by the IterableExtension extension
Checks if no element matches the predicate.
noneMatch(ConditionTester<T> test) → bool: Available on Iterable<T>, provided by the IterableExtension extension
Checks if none of the elements match a condition using noneMatch.
noSuchMethod(Invocation invocation) → dynamic: Invoked when a nonexistent method or property is accessed.
inherited
offer(E element) → bool: Inserts the specified element into this queue if it is possible to do so immediately.
peek() → E?: Retrieves, but does not remove, the head of this queue.
poll() → E?: Retrieves and removes the head of this queue.
pop() → T?: Available on List<T>, provided by the ListExtensions extension
Removes and returns the last element of the list.
process(dynamic action(T item)) → void: Available on Iterable<T>, provided by the IterableExtension extension
Processes each element of the iterable using the provided action function.
reduce(E combine(E previousValue, E element)) → E: Reduces a collection to a single value by iteratively combining elements of the collection using the provided function.
inherited
remove(Object? element) → bool: Removes the first occurrence of value from this list.
override
removeAll() → void: Removes all elements from this queue.
removeAllIf(ConditionTester<T> condition, Iterable<T> items) → void: Available on List<T>, provided by the ListExtensions extension
Removes all items from another list if a condition is met.
removeAt(int index) → E: Removes the object at position index from this list.
override
removeElement() → E: Retrieves and removes the head of this queue.
removeFirst() → E: Removes the first element from this queue.
removeIf(ConditionTester<T> condition, T element) → void: Available on List<T>, provided by the ListExtensions extension
Removes an item from a list if a condition is met.
removeLast() → E: Removes the last element from this queue.
override
removeRange(int start, int end) → void: Removes a range of elements from the list.
inherited
removeWhere(bool test(E element)) → void: Removes all elements that satisfy the given predicate.
override
replaceRange(int start, int end, Iterable<E> newContents) → void: Replaces a range of elements with the elements of replacements.
inherited
retainAll(Iterable<Object?> elements) → void: Retains only the elements in this queue that are contained in the specified collection.
retainWhere(bool test(E element)) → void: Removes all objects from this list that fail to satisfy test.
inherited
reverse() → List<T>: Available on List<T>, provided by the ListExtensions extension
Returns a new list with the elements in reverse order.
setAll(int index, Iterable<E> iterable) → void: Overwrites elements with the objects of iterable.
inherited
setRange(int start, int end, Iterable<E> iterable, [int skipCount = 0]) → void: Writes some elements of iterable into a range of this list.
inherited
shift() → T?: Available on List<T>, provided by the ListExtensions extension
Removes and returns the first element of the list.
shuffle([Random? random]) → void: Shuffles the elements of this list randomly.
inherited
singleWhere(bool test(E element), {E orElse()?}) → E: The single element that satisfies test.
inherited
size() → int: Returns the number of elements in this queue.
skip(int count) → Iterable<E>: Creates an Iterable that provides all but the first count elements.
inherited
skipWhile(bool test(E element)) → Iterable<E>: Creates an Iterable that skips leading elements while test is satisfied.
inherited
sort([int compare(E a, E b)?]) → void: Sorts this list according to the order specified by the compare function.
override
sortedByPublicFirst() → List<T>: Available on Iterable<T>, provided by the SortByPublic extension
Sorts declarations with public visibility before private ones.
sortedByPublicFirstThenSyntheticLast() → List<T>: Available on Iterable<T>, provided by the SortByPublic extension
Sorts declarations with public visibility first and synthetic declarations last.
stream() → GenericStream<T>: Available on Iterable<T>, provided by the IterableExtension extension
Converts the iterable to a stream.
sublist(int start, [int? end]) → List<E>: Returns a new list containing the elements between start and end.
override
take(int count) → Iterable<E>: Creates a lazy iterable of the count first elements of this iterable.
inherited
takeWhile(bool test(E element)) → Iterable<E>: Creates a lazy iterable of the leading elements satisfying test.
inherited
toArray() → List<E>: Returns an array containing all of the elements in this queue.
toList({bool growable = true}) → List<E>: Creates a List containing the elements of this Iterable.
override
toMap<K, V>(K keySelector(T item), V valueSelector(T item)) → Map<K, V>: Available on Iterable<T>, provided by the IterableExtension extension
Maps the iterable to a new iterable using the provided mapper function.
toSet() → Set<E>: Creates a Set containing the same elements as this iterable.
inherited
toString() → String: A string representation of this object.
override
where(bool test(E element)) → Iterable<E>: Creates a new lazy Iterable with all elements that satisfy the predicate test.
inherited
whereOrNull(ConditionTester<T> test) → Iterable<T>?: Available on Iterable<T>, provided by the IterableExtension extension
Returns an iterable with elements that match a condition, or null if none match.
whereType<U>() → Iterable<T>: Available on Iterable<T>, provided by the IterableExtension extension
Filters elements of a specific type T.
whereType<T>() → Iterable<T>: Creates a new lazy Iterable with all elements that have type T.
inherited

Operators

operator +(List<E> other) → List<E>: Returns the concatenation of this list and other.
inherited
operator ==(Object other) → bool: The equality operator.
inherited
operator [](int index) → E: The object at the given index in the list.
override
operator []=(int index, E value) → void: Sets the value at the given index in the list to value.
override