无法在实现Comparator的类中调用自定义方法

Question

I am having this issue where I have a PiorityBlockingQueue to sort the items in it. The are several options the user can sort the items being added into the queue.

The one I'm stuck at is trying to order the queue by the most occurences of an Item .

The choice of the comparison is determined in the constructor of MyQueue . But the counts of (eg. Low, Medium, High) isnt determined until later. When it is determined, I wanted to call the update(String lst) method from ItemComparator to update the hashmap so that the sorting is correct.

So my issue is I can't call that method. I know I'm missing something but I can't figure it out. Any help? Maybe there a better design than what I doing now?

 public class ItemComparator implements Comparator<Item>
    {        
         public void update(String lst){
             test = lst;
         }

         public int compare(Item o1, Item o2) {
            HashMap<String,Integer> priority = new HashMap<>();
            priority.put("LOW", 1);
            priority.put("MEDIUM", 2);
            priority.put("HIGH", 3);

            if (priority.get(o1.getPriority()) > priority.get(o2.getPriority())) {
                return -1;
            }
            if (priority.get(o1.getPriority()) < priority.get(o2.getPriority())) {
                return 1;
            }
            return 0;
         }    
    }

This statement wont work from this class comparator.update(aString);

public class MyQueue implements AQueue{

    private Comparator<Ticket> comparator;
    private PriorityBlockingQueue<Ticket> listOfTickets;
    private String policy;

    BlockingQImpl(String processingPolicy) throws InvalidDataException {
        setPolicy(processingPolicy.toUpperCase());
        setComparator(policy);
    }

    private void setComparator(String policy) throws InvalidDataException {
        if (policy.equals("THIS")) {
            comparator = new ItemComparator(countString);
        } 
        listOfTickets = new PriorityBlockingQueue<>(10, comparator);
    }

    public void addList(int id) {
        ticks.add(id)
        comparator.update(aString);
    }
}

Answer 1

I think your problem is the compilation error at comparator.update(aString); right?

It is because you have declared comparator as Comparator<Ticket> , that means, you are "seeing" it as a Comparator , and in a Comparator , there is no update() method.

You should declare it as ItemComparator

ie

private ItemComparator comparator;