/** * Store an end-point to host ID mapping. Each ID must be unique, and cannot be changed after the * fact. * * @param hostId * @param endpoint */ public void updateHostId(UUID hostId, InetAddress endpoint) { assert hostId != null; assert endpoint != null; lock.writeLock().lock(); try { InetAddress storedEp = endpointToHostIdMap.inverse().get(hostId); if (storedEp != null) { if (!storedEp.equals(endpoint) && (FailureDetector.instance.isAlive(storedEp))) { throw new RuntimeException( String.format( "Host ID collision between active endpoint %s and %s (id=%s)", storedEp, endpoint, hostId)); } } UUID storedId = endpointToHostIdMap.get(endpoint); if ((storedId != null) && (!storedId.equals(hostId))) logger.warn("Changing {}'s host ID from {} to {}", endpoint, storedId, hostId); endpointToHostIdMap.forcePut(endpoint, hostId); } finally { lock.writeLock().unlock(); } }