如何将类对象用于其他对象？

Question

I'll give an example to explain what i need, imagine a Lamborghini database:

CarSeries (int identifier, String name)
CarModel (int modelIdentifier, String modelName, CarSeries (int identifier, String name);

Now I want to create an array where I should be able to directly create a carModel , for example a carModel (123, Gallardo, 345, Superleggera)

So I create the array for three cars:

CarModel carmodels[] = new CarModel[3];

And have to initialize them. Initializing a similar array 0 position for CarSeries is as simple as

carseries[0] = new CarSeries(0,"");

but I can't find the way to initialize a CarModel, and neither to use getters and setters for, for example, set carModel carSeries's identifier.

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Update: Based in RAZ_Muh_Taz's code (very helpful, thanks!) I've been able to initialize it! This way: carmodels[0] = new CarModel (0,"", new CarSeries(0,"")); Now i want to set a console output asking for CarSeries identifier, how should code ask for input? How can I use the getter now?

Update2: Finally just created a new array for each Person and just update both arrays simultaneously with same count to point both desired groups of data.

Answer 1

Your third parameter is a CarSeries , so just pass that in.

CarSeries accord = new CarSeries (0, "accord");
CarModel honda = new CarModel(0, "honda", accord);

Or in-line.

CarModel honda = new CarModel(0, "Honda", new CarSeries (0, "Accord"));

Whether that is in an array or not is not a problem, though, I think you should ideally store some collection of series for each model, not only one.

Answer 2

You need to create a new object when passing it to your parameter in your CarModel contructor.

CarModel carmodels[] =  new CarModel[3];
carseries[0] = CarModel (0, "Lexus", new CarSeries (0, "RX350"));
carseries[1] = CarModel (1, "Toyota", new CarSeries (1, "Tacoma"));
carseries[2] = CarModel (2, "Honda", new CarSeries (2, "CR-V"));

Answer 3

You can do it the following way provided you have the appropriate constructors for CarModel and CarSeries defined.

CarModel carmodels[] =  new CarModel[3] {
    new CarModel(1, "gallardo", new CarSeries(100, "xyz")), 
    new CarModel(2, "veneno", new CarSeries(200, "abc"), 
    new CarModel(3, "Huracan", new CarSeries(300, "pqr") 
};

Answer 4

Once you have declared the carmodel array, you have to access to the index of the array to insert each one car models.

CarModel carModels[] = new CarModel[3];

carModels[0] = new CarModel(0, "model1", new CarSeries(0, "serie1"));
carModels[1] = new CarModel(1, "model2", new CarSeries(1, "serie2"));
carModels[2] = new CarModel(2, "model3", new CarSeries(2, "serie3"));

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You can also declare the CarSeries before

CarSeries carSerie1 = new CarSeries(0, "serie1");
CarSeries carSerie2 = new CarSeries(1, "serie2");
CarSeries carSerie3 = new CarSeries(2, "serie3");

and use the reference in the constructor of the CarModel

carModels[0] = new CarModel(0, "model1", carSerie1);
carModels[1] = new CarModel(1, "model2", carSerie2);
carModels[2] = new CarModel(2, "model3", carSerie3);

You have to take into account that you have to declare the constructors properly or the code won´t compile

Answer 5

You'd bether to use Map interface.

Map<Object, Object>yourMapName = new HashMap<Object, Object>();

But I recommend to you to read much more for collections and their hierarchy .

Answer 6

First of all you cannot instantiate your model like that>
What you are doing is: instantiate CarModel with name carmodels[]

You can do a arraylist