Question

I’m designing a simple car rental system and was wondering whether I was using good practice for the design. Basically, I have a showroom arraylist, which stores all rental cars (new objects). Inside each car object is an arraylist for the availability of that car for that month. The availability comprises of 31 values (corresponding to each day in that month), either 0 or 1 (available). They are initially set to 1 until a car is booked for that day. Is there another way of incorporating availability?

ArrayList<Car> showroom = new ArrayList<Car>();

ArrayList<Integer> Available1 = new ArrayList<Integer>();
ArrayList<Integer> Available2 = new ArrayList<Integer>();

setAllDatesAvailable(Available1);
setAllDatesAvailable(Available2);

Car number1 = new Car(objectitems, ... , Available1);
showroom.add(number1);
Car number2 = new Car(objectitems, ... , Available2);
showroom.add(number2);

//booking process

setAllDatesAvailable(ArrayList Array) {
   for (int i = 0; i < 31; i++) {
      Array.add(1);
}

NB:

• i’m not worried about timestamps, assume that the car is booked for
  the whole day
• assume that the system is only for a single month of 31 days

Answer 1

Here are some improvements that I would suggest for your code: –

1. First, follow Java Naming Conventions. Variable name should start with lowercase letters. Available -> available, or even better, availableDates to match the purpose of your List

2. Always use Generic Type collections.

   setAllDatesAvailable(ArrayList Array)
   

   to:

   setAllDatesAvailable(ArrayList<Integer> array);
   

3. Use Interface as your Reference types. You should declare your list as: –

   List<Integer> availableDates = new ArrayList<Integer>();
   

   Same thing also in the formal parameters in your methods, as shown in comment by @Alex.

4. Choose meaningful name for your variables.

   Car number1 = ...; <-- // makes no sense to reader
   

   change it to: –

   Car car1 = ...;
   

5. As far as possible, try to name your formal parameters same as of your actual parameters.

   setAllDatesAvailable(ArrayList<Integer> array);
   

   should better be declared as: –

   setAllDatesAvailable(List<Integer> availableDates);
   

After all these changes, you can look forward to improvise the functionality of your code, which @DNA has very nicely written in his answer.