description

# LinkedList<E extends LinkedListEntry<E>> class base

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:

    final 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
  - Object
  - Iterable<E>
  - LinkedList

## Constructors

LinkedList()
  Constructs a new empty linked list.

## Properties

first → E
  The first element.
  no setteroverride
hashCode → int
  The hash code for this object.
  no setterinherited
isEmpty → bool
  Whether this collection has no elements.
  no setteroverride
isNotEmpty → bool
  Whether this collection has at least one element.
  no setterinherited
iterator → Iterator<E>
  A new `Iterator` that allows iterating the elements of this `Iterable`.
  no setteroverride
last → E
  The last element.
  no setteroverride
length → int
  The number of elements in this Iterable.
  no setteroverride
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

## 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<T>
  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 `index`th 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
  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 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
  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(E entry) → bool
  Removes `entry` from the linked list.
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 element)) → Iterable<E>
  Creates an `Iterable` that skips leading elements while `test` 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 element)) → 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
  Returns a string representation of (some of) the elements of `this`.
  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