pkg/observe/lib/src/metadata.dart

// 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;

/**
 * Use `@observable` to make a field automatically observable, or to indicate
 * that a property is observable.
 */
const ObservableProperty observable = const ObservableProperty();

/**
 * An annotation that is used to make a property observable.
 * Normally this is used via the [observable] constant, for example:
 *
 *     class Monster {
 *       @observable int health;
 *     }
 *
 * If needed, you can subclass this to create another annotation that will also
 * be treated as observable.
 */
// Note: observable properties imply reflectable.
class ObservableProperty {
  const ObservableProperty();
}


/**
 * Use `@reflectable` to make a type or member available to reflection in the
 * observe package. This is necessary to make the member visible to
 * [PathObserver], or similar systems, once the code is deployed.
 */
const Reflectable reflectable = const Reflectable();

/**
 * An annotation that is used to make a type or member reflectable. This makes
 * it available to [PathObserver] at runtime. For example:
 *
 *     @reflectable
 *     class Monster extends ChangeNotifier {
 *       int _health;
 *       int get health => _health;
 *       ...
 *     }
 *     ...
 *       // This will work even if the code has been tree-shaken/minified:
 *       final monster = new Monster();
 *       new PathObserver(monster, 'health').changes.listen(...);
 */
class Reflectable {
  const Reflectable();
}