private Size.Unit convertToUnit(String unitSimpleName) {
    for (Size.Unit unit : Size.Unit.values()) {
      if (unitSimpleName.equals(unit.getSimpleName())) {
        return unit;
      }
    }
    throw new IllegalArgumentException("invalid size");
  }
Represents a value of a field. The type of a value is defined by {@link FieldValue}.
hbase-hbtop/src/main/java/org/apache/hadoop/hbase/hbtop/field/FieldValue.java