Base implementation for ListenersManager.
A CallableListenersManager allows to invoke methods on registered listeners,
by using call.
Class to hold an arbitrary number of items. When storing less than five items,
this class will not use any additional object.
An object that allows to register (and unregister) listeners.
A ListenersManager that does nothing. It can be used in situations where it
is known that listeners won't ever be invoked
This implementation of ListenersManager is the easiest to use.
Through reflection, it is possible to use it without the need to write any
Class to hold up to 5 items.
This class is used to hold an object weakly.