String.compareTo method to compare

Question

Will you check my Method and let me know what I'm doing wrong? thank you :)

public static void sortByVehicleMakeModel(Vehicle[] vehicles) {
    boolean swapped = true;

    for(int y = 0; y < vehicles.length && swapped; y++) {
        swapped=false;
        for(int x = 0; x < vehicles.length - (y+1); x++) {
            if(vehicles[x].getMake() && vehicles[x].getModel().compareTo(vehicles[x + 1].getMake() && vehicles[x].getModel())) {    
                swap(vehicles, x, x + 1);
                swapped=true;
            }
        }
    }
}

my error is on the second statement .compareto() The operator && is undefined for the argument type(s) java.lang.String, java.lang.String

However, this code works just fine:

public static void sortByOwnerName(Vehicle[] vehicles) {
    boolean swapped = true;

    for(int y = 0; y < vehicles.length && swapped; y++) {
        swapped=false;
        for(int x = 0; x < vehicles.length - (y + 1); x++) {
            if(vehicles[x].getOwner().getName().compareTo(vehicles[x + 1].getOwner().getName())> 0) {   
                swap(vehicles, x, x + 1);
                swapped=true;
            }
        }
    }
}

Answer 1

I would suggest adding a int getCost() to the Vehicle object and then using something like vehicles[x].getCost() > vehicles[x - 1].getCost() for your if statement.

Also, this sort is not very efficient. Maybe Vehicle should implement Comparable and use Collections.sort() to sort.

---

Just read the update to your question.

Try this:

if (vehicles[x].getMake().compareTo(vehicles[x - 1].getMake()) < 0 || 
   (vehicles[x].getMake().compareTo(vehicles[x - 1].getMake()) == 0 &&
    vehicles[x].getModel().compareTo(vehicles[x - 1].getModel()) < 0)) {