object list sorting

[karq]

Hey!


If i want to sort a object list by a random variable do I really have to make implementation class for every variable?

example:
list of car objects

class car {
    int id;
    String brand;
    int year;
//Setters & getters

}
class carID implements Comparable{
public int compare(Object car, Object anotherCar) {
    int id = car.getId();
    int id2 =  anotherCar.getId();
   
      return id.compareTo(id2);
    
  }
}
class carBrand implements Comparable{
public int compare(Object car, Object anotherCar) {
    String brand = car.getBrand();
    String brand2 =  anotherCar.getBrand();
   
      return brand.compareTo(brand2);
    
  }
}

.....

Or is there another way?

[KevinWorkman]

Class names should start with upper-case letters. But you could also do something like this:

class carID implements Comparable{
public int compare(Object car, Object anotherCar) {
   if(condition){
      int id = car.getId();
      int id2 =  anotherCar.getId();
      return id.compareTo(id2);
   }
   else{
       String brand = car.getBrand();
       String brand2 =  anotherCar.getBrand();
       return brand.compareTo(brand2);
    }
}

Then just set the condition of the comparing class whenever you want to use it. I don't really see the "problem" you're trying to work around, though.

[KevinWorkman]

You also might want to use an anonymous inner class for each sort:

Collections.sort(yourList, new Comparator<Car>(){
   public int compareTo(Car car1, Car car2){
      //...
   }
});

Again, depends on your requirements, which you haven't really explained.