/**
* Registers the specified listener with this provider so that it would receive notifications on
* changes of its state or other properties such as its local address and display name.
*
* @param listener the listener to register.
*/
public void addRegistrationStateChangeListener(RegistrationStateChangeListener listener) {
synchronized (registrationStateListeners) {
if (!registrationStateListeners.contains(listener)) registrationStateListeners.add(listener);
}
}
