LinkedList<E extends LinkedListEntry<E>> class Null safety

A specialized double-linked list of elements that extends LinkedListEntry.

This is not a generic data structure. It only accepts elements that extend the LinkedListEntry class. See the Queue implementations for generic collections that allow constant time adding and removing at the ends.

This is not a List implementation. Despite its name, this class does not implement the List interface. It does not allow constant time lookup by index.

Because the elements themselves contain the links of this linked list, each element can be in only one list at a time. To add an element to another list, it must first be removed from its current list (if any). For the same reason, the remove and contains methods are based on identity, even if the LinkedListEntry chooses to override Object.==.

In return, each element knows its own place in the linked list, as well as which list it is in. This allows constant time LinkedListEntry.insertAfter, LinkedListEntry.insertBefore and LinkedListEntry.unlink operations when all you have is the element.

A LinkedList also allows constant time adding and removing at either end, and a constant time length getter.

Example:

class EntryItem extends LinkedListEntry<EntryItem> {
  final int id;
  final String text;
  EntryItem(this.id, this.text);

  @override
  String toString() {
    return '$id : $text';
  }
}

void main(){
  final linkedList = LinkedList<EntryItem>();
  linkedList.addAll(
      [EntryItem(1, 'A'), EntryItem(2, 'B'), EntryItem(3, 'C')]);
  print(linkedList.first); // 1 : A
  print(linkedList.last); // 3 : C

  // Add new item after first item.
  linkedList.first.insertAfter(EntryItem(15, 'E'));
  // Add new item before last item.
  linkedList.last.insertBefore(EntryItem(10, 'D'));
  // Iterate items.
  for (var entry in linkedList) {
    print(entry);
    // 1 : A
    // 15 : E
    // 2 : B
    // 10 : D
    // 3 : C
  }

  // Remove item using index from list.
  linkedList.elementAt(2).unlink();
  print(linkedList); // (1 : A, 15 : E, 10 : D, 3 : C)
  // Remove first item.
  linkedList.first.unlink();
  print(linkedList); // (15 : E, 10 : D, 3 : C)
  // Remove last item from list.
  linkedList.remove(linkedList.last);
  print(linkedList); // (15 : E, 10 : D)
  // Remove all items.
  linkedList.clear();
  print(linkedList.length); // 0
  print(linkedList.isEmpty); // true
}
Inheritance
Available Extensions

Constructors

LinkedList()
Constructs a new empty linked list.

Properties

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

Methods

add(E entry) → void
Adds entry to the end of the linked list.
addAll(Iterable<E> entries) → void
Adds entries to the end of the linked list.
addFirst(E entry) → void
Adds entry to the beginning of the linked list.
any(bool test(E 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
Remove all elements from this linked list.
contains(Object? entry) bool
Whether entry is a LinkedListEntry belonging to this list. [...]
override
elementAt(int index) → E
Returns the indexth element. [...]
inherited
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 action(E entry)) → void
Call action with each entry in this linked list. [...]
override
join([String separator = ""]) String
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 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(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(E entry) bool
Removes entry from the linked list. [...]
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 value)) 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 value)) 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. [...]
inherited
toSet() Set<E>
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(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