| // Copyright (c) 2013, the Dart project authors. Please see the AUTHORS file |
| // for details. All rights reserved. Use of this source code is governed by a |
| // BSD-style license that can be found in the LICENSE file. |
| |
| part of dart.collection; |
| |
| /** |
| * A hash-table based implementation of [Map]. |
| * |
| * The keys of a `HashMap` must have consistent [Object.operator==] |
| * and [Object.hashCode] implementations. This means that the `==` operator |
| * must define a stable equivalence relation on the keys (reflexive, |
| * anti-symmetric, transitive, and consistent over time), and that `hashCode` |
| * must be the same for objects that are considered equal by `==`. |
| * |
| * The map allows `null` as a key. |
| */ |
| class HashMap<K, V> implements Map<K, V> { |
| external HashMap(); |
| |
| /** |
| * Creates a [HashMap] that contains all key value pairs of [other]. |
| */ |
| factory HashMap.from(Map<K, V> other) { |
| return new HashMap<K, V>()..addAll(other); |
| } |
| |
| /** |
| * Creates a [HashMap] where the keys and values are computed from the |
| * [iterable]. |
| * |
| * For each element of the [iterable] this constructor computes a key/value |
| * pair, by applying [key] and [value] respectively. |
| * |
| * The keys of the key/value pairs do not need to be unique. The last |
| * occurrence of a key will simply overwrite any previous value. |
| * |
| * If no values are specified for [key] and [value] the default is the |
| * identity function. |
| */ |
| factory HashMap.fromIterable(Iterable iterable, |
| {K key(element), V value(element)}) { |
| HashMap<K, V> map = new HashMap<K, V>(); |
| Maps._fillMapWithMappedIterable(map, iterable, key, value); |
| return map; |
| } |
| |
| /** |
| * Creates a [HashMap] associating the given [keys] to [values]. |
| * |
| * This constructor iterates over [keys] and [values] and maps each element of |
| * [keys] to the corresponding element of [values]. |
| * |
| * If [keys] contains the same object multiple times, the last occurrence |
| * overwrites the previous value. |
| * |
| * It is an error if the two [Iterable]s don't have the same length. |
| */ |
| factory HashMap.fromIterables(Iterable<K> keys, Iterable<V> values) { |
| HashMap<K, V> map = new HashMap<K, V>(); |
| Maps._fillMapWithIterables(map, keys, values); |
| return map; |
| } |
| |
| external int get length; |
| external bool get isEmpty; |
| external bool get isNotEmpty; |
| |
| external Iterable<K> get keys; |
| external Iterable<V> get values; |
| |
| external bool containsKey(Object key); |
| external bool containsValue(Object value); |
| |
| external void addAll(Map<K, V> other); |
| |
| external V operator [](Object key); |
| external void operator []=(K key, V value); |
| |
| external V putIfAbsent(K key, V ifAbsent()); |
| |
| external V remove(Object key); |
| external void clear(); |
| |
| external void forEach(void action(K key, V value)); |
| |
| String toString() => Maps.mapToString(this); |
| } |