| // 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 observe; |
| |
| // TODO(jmesserly): should the property name be configurable? |
| // That would be more convenient. |
| /** |
| * An observable box that holds a value. Use this if you want to store a single |
| * value. For other cases, it is better to use [ObservableList], |
| * [ObservableMap], or a custom [Observable] implementation based on |
| * [ObservableMixin]. The property name for changes is "value". |
| */ |
| class ObservableBox<T> extends ChangeNotifierBase { |
| T _value; |
| |
| ObservableBox([T initialValue]) : _value = initialValue; |
| |
| T get value => _value; |
| |
| void set value(T newValue) { |
| _value = notifyPropertyChange(const Symbol('value'), _value, newValue); |
| } |
| |
| String toString() => '#<$runtimeType value: $value>'; |
| } |