Set<Provider> oldProviders = serviceToProviders.get(services.toArray()[0]);
Provider oldProvider = (Provider) oldProviders.toArray()[0];
// Since IP already has service to bind with, the oldProvider can't be null
Set<Provider> newProviders = serviceToProviders.get(service);
if (newProviders == null || newProviders.isEmpty()) {
throw new InvalidParameterException("There is no new provider for IP " + publicIp.getAddress() + " of service " + service.getName() + "!");
}
Provider newProvider = (Provider) newProviders.toArray()[0];
if (!oldProvider.equals(newProvider)) {
throw new InvalidParameterException("There would be multiple providers for IP " + publicIp.getAddress() + "!");
}
return true;
}