@Override
  public String toString() {
    switch (type) {
      case STRING:
      case INTEGER:
      case LONG:
      case FLOAT:
        return value.toString();

      case SIZE:
        Size size = (Size) value;
        return String.format("%.1f", size.get()) + size.getUnit().getSimpleName();

      case PERCENT:
        return String.format("%.2f", (Float) value) + "%";

      default:
        throw new AssertionError();
    }
  }
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