method
add_observer

add_observer(observer, func=:update)
public
Add observer as an observer on this object. so that it will receive notifications.
observer |
the object that will be notified of changes. |
func |
Symbol naming the method that will be called when this Observable |
has changes. This method must return true for +observer.respond_to?+ and will receive <tt>*arg</tt> when #notify_observers is called, where <tt>*arg</tt> is the value passed to #notify_observers by this Observable