private static Field getField(List<Field> fields, String fieldString) {
    for (Field f : fields) {
      if (f.getHeader().equals(fieldString)) {
        return f;
      }
    }
    return null;
  }
Represents a filter that's filtering the metric {@link Record}s.
hbase-hbtop/src/main/java/org/apache/hadoop/hbase/hbtop/RecordFilter.java