util for simple duration formatting

DurationFormatter.java

import java.time.Duration;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.concurrent.TimeUnit;

/**
 * @author Johnny_JayJay (https://www.github.com/JohnnyJayJay)
 */
public final class DurationFormatter {

  private static final Map<TimeUnit, Integer> unitSizes = new LinkedHashMap<>();

  static {
    int ms = 1;
    int s = ms * 1000;
    int min = s * 60;
    int h = min * 60;
    int d = h * 24;
    unitSizes.put(TimeUnit.DAYS, d);
    unitSizes.put(TimeUnit.HOURS, h);
    unitSizes.put(TimeUnit.MINUTES, min);
    unitSizes.put(TimeUnit.SECONDS, s);
    unitSizes.put(TimeUnit.MILLISECONDS, ms);
  }

  private DurationFormatter() {}

  public static String format(Duration duration, String formatString, TimeUnit biggestUnit) {
    Iterator<TimeUnit> iterator = unitSizes.keySet().iterator();
    while (iterator.hasNext() && iterator.next() != biggestUnit);
    if (!iterator.hasNext()) {
      throw new IllegalArgumentException();
    }
    TimeUnit current = biggestUnit;
    long remainingMillis = duration.toMillis();
    String result = formatString;
    do {
      long unitSize = unitSizes.get(current);
      long amount = remainingMillis / unitSize;
      result = result.replace("{" + current.name().toLowerCase() + "}", String.valueOf(amount));
      remainingMillis %= unitSize;
      current = iterator.next();
    } while (iterator.hasNext());
    return result;
  }

}

Line 12: Warum eine LinkedHashMap und keine EnumMap?
(Was macht die LinkedHashMap besser in dieser Anwendung?)

Weil diese Reihenfolge wichtig ist. Abgesehen davon wäre es hier sowieso relativ egal, da das eine einmalige Map ist