使用另一个类的compareTo方法

Question

I have a class called classes who has this compareto method:

@Override
public int compareTo(Object other) {
    Cours ot = (Cours)other;
    String heure2 = ot.heure;
    int autre = Integer.parseInt(heure2.substring(0,2));
    int le = Integer.parseInt(this.heure.substring(0,2));

    if (autre > le) {
        return 1;
    }

    if (autre == le) {
        return 0;
    } else {
        return -1;
    }

}

I have another class called day that has a list of classes :

private List<Cours> journee;

And a method to sort the classes:

public void TrieListe() {
    Collections.sort(journee);
}

When I use TrieListe() everything works fine, I can sort the list.

But I've added another class called Weeks which contains a List of Days And now I want to use TrieList() from that class :

private List<Days> leWeek;

public void TrieListe() {
    Collections.sort(leWeek);
}

So how can I use my compareTo method from my classes class using sort() in my Weeks class.

Answer 1

Create a new abstract class AComparableByHour and make your classes extend it.

public abstract class AComparableByHour implements Comparable<AComparableByHour> {

public abstract String getHeure();

// Your comparison method goes here 
@Override
public int compareTo(AComparableByHour ot) {
    String heure2 = ot.getHeure();

    int autre = Integer.parseInt(heure2.substring(0,2));
    int le    = Integer.parseInt(this.getHeure().substring(0,2));

    if( autre > le){
        return 1;
    }

    if( autre == le){
        return 0;
    } else {
        return -1;
    }
}

}

public class Cours extends AComparableByHour {
    // This method is mandatory now. 
    // You could move it to the new superclass
    public String getHeure() {   
          return heure;
    }
    ...
}

public class Days extends AComparableByHour {
    public String getHeure() {
         return heure;
    }
    ...
}

Answer 2

I have a class called classes who has this compareto method:

@Override
public int compareTo(Object other) {

This is already wrong. Your class should implement Comparable<classes> (noting that classes is a truly terrible name for a class, for at least three separate reasons), which will force the method signature to be:

@Override
public int compareTo(classes other) {