A widget that implements this interface can be put in an "enabled" or "disabled" state.

abstract class HasEnabled {

 /**
  * Returns true if the widget is enabled, false if not.
  */
 bool get enabled;

 /**
  * Sets whether this widget is enabled.
  *
  * @param enabled <code>true</code> to enable the widget, <code>false</code>
  *          to disable it
  */
 void set enabled(bool value);
}