private void updateNamespaceCache(String namespace, ListMultimap<String, Permission> nsPerms) {
    PermissionCache<NamespacePermission> cacheToUpdate = new PermissionCache<>();
    updateCache(nsPerms, cacheToUpdate);
    namespaceCache.put(namespace, cacheToUpdate);
    mtime.incrementAndGet();
  }
Updates the internal namespace permissions cache for specified namespace.
@param namespace updated namespace
@param nsPerms   new namespace permissions
hbase-server/src/main/java/org/apache/hadoop/hbase/security/access/AuthManager.java