How can I make a JButton activate a compareTo function?

Question

This is a bit embarrassing. I have a compareTo function that I intend to use on a JButton, so when the user presses it they can see which is the highest ranked object. I already have a Listener class for the JButton but I don't know how to make the Listener use the compareTo function because it needs two parameters.

This is my compareTo function:

public int compareTo(Film film1, Film film2) {
    if (film1.getFinalScore() < film2.getFinalScore()) return -1;
    if (film1.getFinalScore() > film2.getFinalScore()) return 1;
    return 0;

}

And this is the actionPerformed function in the Listener class:

@Override
public void actionPerformed(ActionEvent e) {
    this.cm.compareTo(null, null);

}

The Auto-correct suggested to put the parameters to null to make it work, but it's obviously never as simple as the Auto-Correct suggests.

So, how can I make the Listener perform the compareTo function using all of my objects to list them from highest to lowest?

Thanks in advance!

Answer 1

As you need to compare 2 Films together you can do that in Film Class by implementing Comparable<Film> then implementing the compareTo method in the class.

After That , Hold your films in any collection as ArrayList then simply call Collections.max(films) to get the max film object in the list.

Here is the a Film class for demonstration:

public class Film implements Comparable<Film>{
  int finalScore ;

  public Film(int finalScore){
      this.finalScore = finalScore;
  }

  public int getFinalScore(){
      return this.finalScore;
  }

  @Override
  public int compareTo(Film film2) {
      if (this.getFinalScore() < film2.getFinalScore()) return -1;
      if (this.getFinalScore() > film2.getFinalScore()) return 1;
      return 0;
  }
}

And this is the main :

public static void main(String[] args) {
        ArrayList<Film> films = new ArrayList<>();
        films.add(new Film(100));
        films.add(new Film(400));
        films.add(new Film(200));
        films.add(new Film(300));
        System.out.println(Collections.max(films).getFinalScore());//prints 400     
    }

So your actionPerformed will be like this

@Override
public void actionPerformed(ActionEvent e) {
    Film maxFilm = Collections.max(films);
    //then use maxFilm object to do anything you need

}