Question

My add to hashtable method fails, what have i done wrong? Or what have i missunderstood?

test:

@Test
public void testAddKeyValue() {
    AdminController cont = new AdminController();

    Apartment o1 = new Apartment(1, 4, "Maier B", true);
    ArrayList<Expense> exp = new ArrayList<>();

    cont.addKeyWithList(o1, exp);
    assertTrue(cont.isEmpty()); // ISSUE > the test works if it is true, but it is supposed be  False.
}

repo class:

public class Repository extends HashMap<Apartment, ArrayList<Expense>>{
    private Map<Apartment,ArrayList<Expense>> dic; // last expense object refers to curret month
    Iterator<Map.Entry<Apartment, ArrayList<Expense>>> it;
    public void addKeyWithList(Apartment apt, ArrayList<Expense> exp){
        dic.put(apt, exp);
        }
}

Why is my test not working? Or where in the code have I done something wrong?

Answer 1

Don’t extend HashMap as you’re doing. Use a HashMap and delegate to it:

public class Repository {
    private Map<Apartment, List<Expense>> dic = new HashMap<Apartment, List<Expense>>();

    public void addKeyWithList(Apartment apt, ArrayList<Expense> exp){
        dic.put(apt, exp);
    }

    public boolean isEmpty() {
        return dic.isEmpty();
    }
}

At the moment, Repository is a HashMap, but you don’t store anything in it: you store the values in another HashMap contained in Repository.

Also, storing an iterator in a field is a bad idea. iterators can be used only once. Once they have iterated, the can’t iterate anymore. It should be a local variable.