* @param handler The handler for the event type. Not {@code null}.
* @param <T> The event type
* @throws NullPointerException if any parameters are {@code null}.
*/
public <T> void addProjectEventHandler(Event.Type<T> type, T handler) {
final EventBusManager manager = EventBusManager.getManager();
HandlerRegistration reg = manager.registerHandlerToProject(getProjectId(), checkNotNull(type), checkNotNull(handler));
handlerRegistrations.add(reg);
}