@Override
  public List<TRowResult> getRowWithColumnsTs(ByteBuffer tableName, ByteBuffer row,
    List<ByteBuffer> columns, long timestamp, Map<ByteBuffer, ByteBuffer> attributes)
    throws IOError {

    Table table = null;
    try {
      table = getTable(tableName);
      if (columns == null) {
        Get get = new Get(getBytes(row));
        addAttributes(get, attributes);
        get.setTimeRange(0, timestamp);
        Result result = table.get(get);
        return ThriftUtilities.rowResultFromHBase(result);
      }
      Get get = new Get(getBytes(row));
      addAttributes(get, attributes);
      for (ByteBuffer column : columns) {
        byte[][] famAndQf = CellUtil.parseColumn(getBytes(column));
        if (famAndQf.length == 1) {
          get.addFamily(famAndQf[0]);
        } else {
          get.addColumn(famAndQf[0], famAndQf[1]);
        }
      }
      get.setTimeRange(0, timestamp);
      Result result = table.get(get);
      return ThriftUtilities.rowResultFromHBase(result);
    } catch (IOException e) {
      LOG.warn(e.getMessage(), e);
      throw getIOError(e);
    } finally {
      closeTable(table);
    }
  }
Note: this internal interface is slightly different from public APIs in regard to handling of
the qualifier. Here we differ from the public Java API in that null != byte[0]. Rather, we
respect qual == null as a request for the entire column family. The caller (
{@link #getVerTs(ByteBuffer, ByteBuffer, ByteBuffer, long, int, Map)}) interface IS consistent
in that the column is parse like normal.
hbase-thrift/src/main/java/org/apache/hadoop/hbase/thrift/ThriftHBaseServiceHandler.java