presto-accumulo/src/main/java/io/prestosql/plugin/accumulo/index/ColumnCardinalityCache.java/ColumnCardinalityCache/CacheKey
class ColumnCardinalityCache:        public CacheKey(
                String schema,
                String table,
                String family,
                String qualifier,
                Range range,
                Authorizations auths)
        {
            this.schema = requireNonNull(schema, "schema is null");
            this.table = requireNonNull(table, "table is null");
            this.family = requireNonNull(family, "family is null");
            this.qualifier = requireNonNull(qualifier, "qualifier is null");
            this.range = requireNonNull(range, "range is null");
            this.auths = requireNonNull(auths, "auths is null");
        }