Ordering Array List with custom property

Question

I have array list with clothing sizes in this order: "L", "M", "XL", "XS", "S", "XXL" and i need to put in right order like this: "XS", "S", "M", "L", "XL", "XXL".

Collections.sort(arrayList);

will do the job if i have array with this sample: "38", "36", "34", "40", but not with the above. So i decided to do this with for loop and swapping items inside array list and put them on the right place, but because the size of array list is dynamically changed i can't know for sure which position should i assign.

I'm pretty sure that maybe this is not the right way to go, but i'm all open for suggestions how this can be solved.

Now here is one part of code:

// Sample clothing sizes
    List<String> availableSizes = new ArrayList<>(tempSizes);
    // Sorting array, only works for "34", "38", "36" and etc
    Collections.sort(availableSizes);

    if (availableSizes.size() > 0) {
        for (int i = 0; i < availableSizes.size(); i++) {
            if (availableSizes.get(i).equals("XS")) {
                Collections.swap(availableSizes, i, 0);
            } else if (availableSizes.get(i).equals("S")) {
                Collections.swap(availableSizes, i, 1);
            } else if (availableSizes.get(i).equals("M")) {
                Collections.swap(availableSizes, i, 2);
            } else if (availableSizes.get(i).equals("L")) {
                Collections.swap(availableSizes, i, 3);
            } else if (availableSizes.get(i).equals("XL")) {
                Collections.swap(availableSizes, i, 4);
            } else if (availableSizes.get(i).equals("XXL")) {
                Collections.swap(availableSizes, i, 5);
            }
        }
    }

Obviously i will get an error if array size is less than five.

there's a suggestion you can create a List of Pojo say List<Size> in Size put two-member sizeinCms,sizeinLetters, now you can sort it easily using sizeinCms as it will be an integer and will make your list sorted — Pratik Vyas
– Pratik Vyas, Commented May 26, 2017 at 10:34
But i'm not getting both sizesInCm and sizesInLetters. Either will be in cms or in letters. — Dusan Dimitrijevic
– Dusan Dimitrijevic, Commented May 26, 2017 at 10:36
A more maintainable solution might be to create an enum to store the sizes and their 'value' - a number which can be sorted without a custom comparator — MTCoster
– MTCoster, Commented May 26, 2017 at 10:44

Pshemo · Accepted Answer · 2017-05-26 11:06:59Z

8

Store sizes in right order in some list or map (for possible performance increase). Then you can create your own Comparator which will check position of searched size in that list/map and compare it to position of other element. All you need to do is compare these positions.

Something like:

private static Comparator<String> sizeComparator = new Comparator<String>() {

    private Map<String,Integer> sizes = new HashMap<>();
    {
        int i=0;
        for (String size : new String[]{"XS", "S", "M", "L", "XL", "XXL"}){
            sizes.put(size,i++);
        }
    }

    @Override
    public int compare(String o1, String o2) {
        return Integer.compare(sizes.get(o1),sizes.get(o2));
    }

};

Usage:

List<String> list = Arrays.asList("L", "M", "XL", "XS", "S", "XXL" );
System.out.println(list);
list.sort(sizeComparator);
System.out.println(list);

Output:

[L, M, XL, XS, S, XXL] //before sorting
[XS, S, M, L, XL, XXL] //after sorting

edited May 26, 2017 at 11:06

answered May 26, 2017 at 10:36

Pshemo

125k25 gold badges194 silver badges280 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Dusan Dimitrijevic Over a year ago

Great solution! Thanks a million.

Collectives™ on Stack Overflow

Ordering Array List with custom property

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related