Arraylist and InsertionSort Object

Question

Question

I need to use Insertionsort to sort my ArrayList of <klant> on an element (Achternaam). How do i do that?

Code

The code im using for insertion sort gives me a few errors because i am using a Arraylist instead of the 1000's of examples with array's.

public class InsertionSort {

public static void insertionSort(ArrayList<Klant> klanten){
    for(int i = 1; i <klanten.size(); i++){
        Comparable objectToSort = klanten.get(i);
        int j = i;
        while(j > 0 && klanten[j-1].compareTo(objectToSort) > 1){
            klanten[j] = klanten[j-1];
            j--;
        }
        klanten[j] = objectToSort;
    }
}
}

The Klant.class has several getters and setters which return its variables one of them is getAchternaam() which returns the achternaam String.

calling the code:

ArrayList<Klant> klanten = new ArrayList<Klant>();
InsertionSort stringsort = new InsortionSort();
stringsort.insertionSort(klanten);

What am i doing wrong and how can i fix it?

Everywhere in the code insertionSort.class at klanten is a error

'The type expression must be an array but it resolved to ArrayList < klant>

Answer 1

With an array you can examine and assign elements using the [] operator. With a List you need to use get and set methods.

So, where you want to assign an object to a position in the list, you use:

klanten.set(index, object);

and where you want to get an object from a position in the list, you use:

klanten.get(index);

Edit:

Also compareTo(...) > 1 is wrong. The only significance of a compareTo return value is if it is greater, less than or equal to zero. Comparing it to 1 is not going to help your sorting.