private CounterSlice<String> queryLastCounts(Long key, String columnFamily,
                                                            int maxLength) {
    SliceCounterQuery<Long, String> query =
            HFactory.createCounterSliceQuery(cassandra.getKeyspace(),
                                                            LONG_S, STRING_S);
    query
        .setColumnFamily(columnFamily)
        .setKey(key)
        .setRange("", "", true, maxLength);
    return query.execute().get();
}

Caused by: InvalidRequestException(why:String didn't validate.)
at org.apache.cassandra.thrift.Cassandra$get_slice_result.read(Cassandra.java:7756)
at org.apache.cassandra.thrift.Cassandra$Client.recv_get_slice(Cassandra.java:570)
at org.apache.cassandra.thrift.Cassandra$Client.get_slice(Cassandra.java:542)
at me.prettyprint.cassandra.service.KeyspaceServiceImpl$8.execute(KeyspaceServiceImpl.java:308)
... 25 more