There is a list of String currency ISO codes in random order: CHF, USD, AUD, EUR, 0995, AED... etc.
Is there an algorithm to sort it in the following order: first should go only main currencies (USD, CHF, EUR) - in exactly this order, then alphabetically all other currencies, then all numeric currency codes?
As of now i do it in 3 steps by simply creating 3 separate lists, sorting them accordingly and then making list.addAll. Would appreciate any help
Creating a custom comparator would be the ideal way to tackle this scenario.
public class CurrencyComparator implements Comparator<String> {
public static void main(String[] args) {
List<String> currencyList = Arrays.asList("CHF", "USD", "AUD", "EUR", "0995", "AED");
currencyList.sort(new CurrencyComparator());
currencyList.forEach(System.out::println);
}
private int getTypeOrder(String cur) {
switch (cur) {
case "USD":
return 0;
case "CHF":
return 1;
case "EUR":
return 2;
default:
return cur.matches("[A-Za-z]*") ? 3 : 4;
}
}
@Override
public int compare(String cur1, String cur2) {
int typeOrder1 = getTypeOrder(cur1);
int typeOrder2 = getTypeOrder(cur2);
if (typeOrder1 != typeOrder2) {
return Integer.compare(typeOrder1, typeOrder2);
}
return cur1.compareTo(cur2);
}
}
It will produce the below output
USD
CHF
EUR
AED
AUD
0995
