Creating objects via txt file into an array in Java

Question

I am trying to complete a little program.

I\'ve got a text file (.txt) to store different data on objects that i\'ve got.

The structure of the file is the next (

Answer 1

You can look at my solution here below (I also corrected/simplified some problems with the variables for reading the file, anyway this was not the main topic):

public static void loadCars() {
    FileReader fopen;
    BufferedReader opened;
    String line;

    ArrayList carList = new ArrayList();
    try {
        fopen = new FileReader("data.txt");
        opened = new BufferedReader(fopen);

        int nFields = 5; // we have 5 fields in the Car class
        String[] fields = new String[nFields]; // to temporary store fields values read line by line
        int lineCounter = 0;
        while ((line = opened.readLine()) != null) {
            fields[lineCounter] = line;
            lineCounter++;
            if ((lineCounter) % nFields == 0) { //it means we have all 5 fields values for a car
                carList.add(new Car(fields)); //therefore we create a new car and we add it to the list of cars
            }

        }
        opened.close();
    } catch (IOException e) {
        System.out.println("File doesn't exist !");
    }
}

Basically we use an ArrayList to store all the cars, and we read the file, waiting to have all the fields values in order to create the Car object. I store the fields values in an array of Strings: I don't know how you implemented the Car class, but maybe it is useful to create a constructor that takes as parameter an array of strings, so it can set the fields, for instance:

class Car {

    private String type;
    private String year;
    private String milage;
    private String fuel;
    private String color;

    public Car(String[] fields) {
        type=fields[0];
        year=fields[0];
        milage=fields[0];
        fuel=fields[0];
        type=fields[0];
    }
}

But I've to say that probably this is a little 'too static'. For simplicity I assumed that all your fields are of String type, but probably fields like 'year' or 'milage' might be of int type. In this case you can use array of Object[] (instead of String[]), and then cast the value with the right type.

I hope this may help you.