I am implementing a registrars office simulation in where there are four different lines that students can get into. The four lines are as follows...

LinkedList

Priority Queue

Stack

And an ArrayList that students randomly get into

I wanted to ask how I can implement the Comparator in my Priority queue... In my Student class I implemented Comparable and my compareTo method recieves a Student object where I return 1 if this has more credit hours than the Student object. and -1 if the Student object has more credit hours than this.

public int compareTo(Student arg) {
    if (creditHours > arg.getCreditHours()){
        return 1;
    }
    else if (creditHours < arg.getCreditHours()){
        return -1;
    }
    else if (creditHours == arg.getCreditHours()){
        if (inTime > arg.getInTime()){
            return 1;
        }
        else
            return -1;
    }
    return 0;
}

That is the compareTo method and here is my code where I need to implement adding students to this priority queue based on my compareTo method...

else if (nextLineAdd == 1){
                    if (((Deque<Student>) second).peek() == null){
                        ((Deque<Student>) second).add(genius);
                    }
                    else{
                        for (int x = 0; x < second.size(); x  ){
                            second[x].compareTo(genius);
                        }
                    }
                }