Sort Array list of objects based on object attributes

dev_mg99 :

I have list which contains a property class object, In the list i have 3 status

• not_paid
• paid
• part_paid

I want to sort my list below mentioned order.

First - not_paid second- part_paid third -paid

How can I sort my list using Comparator class.?

public static Comparator<OrderHistoryItemData> COMPARE_BY_PAYMENT = new Comparator<OrderHistoryItemData>() {
    public int compare(OrderHistoryItemData one, OrderHistoryItemData other) {
        String p1 = one.getAttributes().getFieldPaymentStatus();
        String p2 = other.getAttributes().getFieldPaymentStatus();
        if (p1.equals(p2)) {
            return 0;
        }
        if (p1.equals("not_paid") && (p2.equals("part_paid") || p2.equals("not_paid"))) {
            return -1;
        }
        if (p1.equals("not_paid") && p2.equals("not_paid")) {
            return -1;
        }
        return 1;
    }
};

This is my Code. i am getting below order using this code.

paid-->not_paid-->part_paid

This is my Update Code. I got my result.

public static Comparator<OrderHistoryItemData> COMPARE_BY_PAYMENT = new Comparator<OrderHistoryItemData>() {
    public int compare(OrderHistoryItemData one, OrderHistoryItemData other) {
        String p1 = one.getAttributes().getFieldPaymentStatus();
        String p2 = other.getAttributes().getFieldPaymentStatus();
        if (p1.equals(p2)) {
            return 0;
        }
        if (p1.equals("not_paid") && (p2.equals("part_paid") || p2.equals("paid"))) {
            return -1;
        }
        if (p1.equals("part_paid") && p2.equals("paid")) {
            return -1;
        }
        return 1;
    }
};

Schidu Luca :

To avoid complex comparator, I encourage you to export your statuses to an enum. (Plus this will work if you will add more statuses in the future, without the need to change logic in your comparator):

enum PaymentStatus { // Write them in order you want to be sorted
    NOT_PAID,
    PART_PAID,
    PAID
}

Then sorting will be as simple as :

list.sort(Comparator.comparing(item ->item.getAttributes().getFieldPaymentStatus()));