Collections sort custom comparator - sorting

Question

I have two classes :
public class Invoice {
private int InvoiceId;
private Customer customer;
private Date invoiceDate;
}
And
public class Customer {
private int customerId;
private String customerType;
}
customerType field can have three values : F,H,B
I have an arrayList of Invoice objects, i want to sort it using the customerType property in a specific order :all the the invoice with customerType "F" then those with "H" then "B".
I tried to implement the Comparator interface , but the problem is that his method compare takes two arguments of Customer objects and the sorting is made in ascending or descending way.
This is the code :
Collections sort(invoicesList, new Comparator<Invoice >() {
public int compare(Invoice s1,Invoice s2) {
return s1.getCustomer().getCustomerTpe().equalsIgnoreCase("F").compareTo(s2.getCustomer().getCustomerTpe().equalsIgnoreCase("H"))
}
}
);
Is there a way to sort my collection with a specific order with three fileds value ?
Thnks

Answer 1

One way to customize the sort order is to first map the arguments and then sort on the mapped values. In your case mapping of the customerType can be done by finding its index in the string "FHB". In Java 8, this might be expressed as
Collections.sort(invoicesList, Comparator.comparingInt(
(invoice) -> "FHB".indexOf( invoice.getCustomer().getCustomerType() )));