SequenceList<E> class / dart:core Library / Dart API Reference

SequenceList<E> class

An unmodifiable List backed by a Sequence.

class SequenceList<E> extends SequenceCollection<E> implements List<E> {
  Sequence<E> sequence;
  SequenceList(this.sequence);

  int get length => sequence.length;

  T operator[](int index) => sequence[index];

  int indexOf(E value, [int start = 0]) {
    for (int i = start; i < sequence.length; i++) {
      if (sequence[i] == value) return i;
    }
    return -1;
  }

  int lastIndexOf(E value, [int start]) {
    if (start == null) start = sequence.length - 1;
    for (int i = start; i >= 0; i--) {
      if (sequence[i] == value) return i;
    }
    return -1;
  }

  E last() => sequence[sequence.length - 1];

  List<E> getRange(int start, int length) {
    List<E> result = <E>[];
    for (int i = 0; i < length; i++) {
      result.add(sequence[start + i]);
    }
    return result;
  }

  void operator []=(int index, E value) {
    throw new UnsupportedOperationException(
        "Cannot modify an unmodifiable list");
  }

  void set length(int newLength) {
    throw new UnsupportedOperationException(
        "Cannot change the length of an unmodifiable list");
  }

  void add(E value) {
    throw new UnsupportedOperationException(
        "Cannot add to an unmodifiable list");
  }

  void addLast(E value) {
    throw new UnsupportedOperationException(
        "Cannot add to an unmodifiable list");
  }

  void addAll(Collection<E> collection) {
    throw new UnsupportedOperationException(
        "Cannot add to an unmodifiable list");
  }

  void sort([Comparator<E> compare]) {
    throw new UnsupportedOperationException(
        "Cannot modify an unmodifiable list");
  }

  void clear() {
    throw new UnsupportedOperationException(
        "Cannot clear an unmodifiable list");
  }

  E removeAt(int index) {
    throw new UnsupportedOperationException(
        "Cannot remove in an unmodifiable list");
  }

  E removeLast() {
    throw new UnsupportedOperationException(
        "Cannot remove in an unmodifiable list");
  }

  void setRange(int start, int length, List<E> from, [int startFrom]) {
    throw new UnsupportedOperationException(
        "Cannot modify an unmodifiable list");
  }

  void removeRange(int start, int length) {
    throw new UnsupportedOperationException(
        "Cannot remove in an unmodifiable list");
  }

  void insertRange(int start, int length, [E initialValue]) {
    throw new UnsupportedOperationException(
        "Cannot insert range in an unmodifiable list");
  }
}

Extends

SequenceCollection<E> > SequenceList<E>

Implements

List<E>

Constructors

new SequenceList(Sequence<E> sequence) #

SequenceList(this.sequence);

Properties

int get length #

The limit of valid indices of the sequence.

The length getter should be efficient.

docs inherited from Sequence<T>

int get length => sequence.length;

void set length(int newLength) #

Changes the length of the list. If newLength is greater than the current length, entries are initialized to null. Throws an UnsupportedOperationException if the list is not extendable.

docs inherited from List<E>

void set length(int newLength) {
  throw new UnsupportedOperationException(
      "Cannot change the length of an unmodifiable list");
}

Sequence<E> sequence #

Sequence<E> sequence;

Operators

operator [](int index) #

Returns the element at the given index in the list or throws an IndexOutOfRangeException if index is out of bounds.

docs inherited from List<E>

T operator[](int index) => sequence[index];

void operator []=(int index, E value) #

Sets the entry at the given index in the list to value. Throws an IndexOutOfRangeException if index is out of bounds.

docs inherited from List<E>

void operator []=(int index, E value) {
  throw new UnsupportedOperationException(
      "Cannot modify an unmodifiable list");
}

Methods

void add(E value) #

Adds value at the end of the list, extending the length by one. Throws an UnsupportedOperationException if the list is not extendable.

docs inherited from List<E>

void add(E value) {
  throw new UnsupportedOperationException(
      "Cannot add to an unmodifiable list");
}

void addAll(Collection<E> collection) #

Appends all elements of the collection to the end of this list. Extends the length of the list by the number of elements in collection. Throws an UnsupportedOperationException if this list is not extendable.

docs inherited from List<E>

void addAll(Collection<E> collection) {
  throw new UnsupportedOperationException(
      "Cannot add to an unmodifiable list");
}

void addLast(E value) #

Adds value at the end of the list, extending the length by one. Throws an UnsupportedOperationException if the list is not extendable.

docs inherited from List<E>

void addLast(E value) {
  throw new UnsupportedOperationException(
      "Cannot add to an unmodifiable list");
}

void clear() #

Removes all elements in the list.

The length of the list becomes zero. Throws an UnsupportedOperationException, and retains all elements, if the length of the list cannot be changed.

docs inherited from List<E>

void clear() {
  throw new UnsupportedOperationException(
      "Cannot clear an unmodifiable list");
}

bool contains(E value) #

inherited from SequenceCollection

Check whether the collection contains an element equal to element.

docs inherited from Collection<E>

bool contains(E value) {
  for (int i = 0; i < sequence.length; i++) {
    if (sequence[i] == value) return true;
  }
  return false;
}

bool every(bool f(E element)) #

inherited from SequenceCollection

Returns true if every elements of this collection satisify the predicate f. Returns false otherwise.

docs inherited from Collection<E>

bool every(bool f(E element)) {
  for (int i = 0; i < this.length; i++) {
    if (!f(this[i])) return false;
  }
  return true;
}

Collection<E> filter(bool f(E element)) #

inherited from SequenceCollection

Returns a collection with the elements of this collection that satisfy the predicate f.

The returned collection should be of the same type as the collection creating it.

An element satisfies the predicate f if f(element) returns true.

docs inherited from Collection<E>

Collection<E> filter(bool f(E element)) {
  List<E> result = <E>[];
  for (int i = 0; i < this.length; i++) {
    E element = this[i];
    if (f(element)) result.add(element);
  }
  return result;
}

void forEach(f(E element)) #

inherited from SequenceCollection

Applies the function f to each element of this collection.

docs inherited from Collection<E>

void forEach(f(E element)) {
  for (int i = 0; i < this.length; i++) f(this[i]);
}

List<E> getRange(int start, int length) #

Returns a new list containing length elements from the list, starting at start. Returns an empty list if length is 0. Throws an ArgumentError if length is negative. Throws an IndexOutOfRangeException if start or start + length - 1 are out of range.

docs inherited from List<E>

List<E> getRange(int start, int length) {
  List<E> result = <E>[];
  for (int i = 0; i < length; i++) {
    result.add(sequence[start + i]);
  }
  return result;
}

int indexOf(E value, [int start = 0]) #

Returns the first index of element in the list.

Searches the list from index start to the length of the list. The first time an element e is encountered so that e == element, the index of e is returned. Returns -1 if element is not found.

docs inherited from List<E>

int indexOf(E value, [int start = 0]) {
  for (int i = start; i < sequence.length; i++) {
    if (sequence[i] == value) return i;
  }
  return -1;
}

void insertRange(int start, int length, [E initialValue]) #

Inserts a new range into the list, starting from start to start + length - 1. The entries are filled with initialValue. Throws an UnsupportedOperationException if the list is not extendable. If length is 0, this method does not do anything. If start is the length of the list, this method inserts the range at the end of the list. Throws an ArgumentError if length is negative. Throws an IndexOutOfRangeException if start is negative or if start is greater than the length of the list.

docs inherited from List<E>

void insertRange(int start, int length, [E initialValue]) {
  throw new UnsupportedOperationException(
      "Cannot insert range in an unmodifiable list");
}

bool isEmpty() #

inherited from SequenceCollection

Returns true if there is no element in this collection.

docs inherited from Collection<E>

bool isEmpty() {
  return this.length == 0;
}

Iterator<E> iterator() #

inherited from SequenceCollection

Returns an Iterator that iterates over this Iterable object.

docs inherited from Iterable<E>

Iterator<E> iterator() => new SequenceIterator(sequence);

E last() #

Returns the last element of the list, or throws an out of bounds exception if the list is empty.

docs inherited from List<E>

E last() => sequence[sequence.length - 1];

int lastIndexOf(E value, [int start]) #

Returns the last index of element in the list.

Searches the list backwards from index start to 0. The first time an element e is encountered so that e == element, the index of e is returned. If start is not provided, it defaults to this.length - 1 . Returns -1 if element is not found.

docs inherited from List<E>

int lastIndexOf(E value, [int start]) {
  if (start == null) start = sequence.length - 1;
  for (int i = start; i >= 0; i--) {
    if (sequence[i] == value) return i;
  }
  return -1;
}

Collection map(f(E element)) #

inherited from SequenceCollection

Returns a new collection with the elements f(e) for each element e of this collection.

Subclasses of Collection should implement the map method to return a collection of the same general type as themselves. E.g., List.map should return a List.

docs inherited from Collection<E>

Collection map(f(E element)) {
  List result = new List();
  for (int i = 0; i < this.length; i++) {
    result.add(f(this[i]));
  }
  return result;
}

reduce(initialValue, combine(previousValue, E element)) #

inherited from SequenceCollection

Reduce a collection to a single value by iteratively combining each element of the collection with an existing value using the provided function. Use initialValue as the initial value, and the function combine to create a new value from the previous one and an element.

Example of calculating the sum of a collection:

collection.reduce(0, (prev, element) => prev + element);

docs inherited from Collection<E>

reduce(initialValue, combine(previousValue, E element)) {
  var value = initialValue;
  for (int i = 0; i < this.length; i++) {
    value = combine(value, this[i]);
  }
  return value;
}

E removeAt(int index) #

Removes the element at position index from the list.

This reduces the length of the list by one and moves all later elements down by one position. Returns the removed element. Throws an ArgumentError if index is not an int. Throws an IndexOutOfRangeException if the index does not point inside the list. Throws an UnsupportedOperationException, and doesn't remove the element, if the length of the list cannot be changed.

docs inherited from List<E>

E removeAt(int index) {
  throw new UnsupportedOperationException(
      "Cannot remove in an unmodifiable list");
}

E removeLast() #

Pops and returns the last element of the list. Throws a UnsupportedOperationException if the length of the list cannot be changed.

docs inherited from List<E>

E removeLast() {
  throw new UnsupportedOperationException(
      "Cannot remove in an unmodifiable list");
}

void removeRange(int start, int length) #

Removes length elements from the list, beginning at start. Throws an UnsupportedOperationException if the list is not extendable. If length is 0, this method does not do anything. Throws an ArgumentError if length is negative. Throws an IndexOutOfRangeException if start or :start + length: - 1 are out of range.

docs inherited from List<E>

void removeRange(int start, int length) {
  throw new UnsupportedOperationException(
      "Cannot remove in an unmodifiable list");
}

void setRange(int start, int length, List<E> from, [int startFrom]) #

Copies length elements of from, starting at startFrom, into the list, starting at start. If length is 0, this method does not do anything. Throws an ArgumentError if length is negative. Throws an IndexOutOfRangeException if start or start + length - 1 are out of range for this, or if startFrom or startFrom + length - 1 are out of range for from.

docs inherited from List<E>

void setRange(int start, int length, List<E> from, [int startFrom]) {
  throw new UnsupportedOperationException(
      "Cannot modify an unmodifiable list");
}

bool some(bool f(E element)) #

inherited from SequenceCollection

Returns true if one element of this collection satisfies the predicate f. Returns false otherwise.

docs inherited from Collection<E>

bool some(bool f(E element)) {
  for (int i = 0; i < this.length; i++) {
    if (f(this[i])) return true;
  }
  return false;
}

void sort([Comparator compare]) #

Sorts the list according to the order specified by the Comparator.

docs inherited from List<E>

void sort([Comparator<E> compare]) {
  throw new UnsupportedOperationException(
      "Cannot modify an unmodifiable list");
}