Array to subclass

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Mike - 29 Jul 2006 05:07 GMT

I am new to this and i don't understand how to transfer my arrays to a
subclass, alter the data and then send it back to the superclass. I
don't want to jump right in, I do some manipulating on the arrays in
the superclass using several methods. I want to pick the point in the
supercalss whent it sends to the subclass and I would like the altyered
data to drop back to the superclass right after the call to subclass.

My superclass: Inventory is passing data to my subclass: ProductXtras.

My supercalss has the following arrays which U want to send to the
subclass and retrieve them after I make changes to them in the
subclass.

final int Array_Length = 50;
// Constant array size
String DVDID[] = new String[Array_Length]; // DVD
identification code
String DVDScreen[] = new String[Array_Length]; // Screen
format 4:3 or 16:9
String DVDName[] = new String[Array_Length]; // DVD title
Double DVDQty[] = new Double[Array_Length]; // Number of
DVDs per title
Double DVDEach[] = new Double[Array_Length]; // Price of each
DVD
Double DVDRestock[] = new Double[Array_Length]; // Restock Price
of each DVD
Double DVDTotal[] = new Double[Array_Length]; // Total value
of DVDs of 1 title
int index;
// Number of array elements used

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Bart Cremers - 29 Jul 2006 08:19 GMT

> I am new to this and i don't understand how to transfer my arrays to a
> subclass, alter the data and then send it back to the superclass. I
> don't want to jump right in, I do some manipulating on the arrays in
> the superclass using several methods. I want to pick the point in the
> supercalss whent it sends to the subclass and I would like the altyered
> data to drop back to the superclass right after the call to subclass.

I'm not sure how the classes are structured, but it's easy to do this
if your superclass is abstract.

public abstract class Super {

public void process(Object[] array) {
// Do a lot of work on the array here
subProcess(array);
// Do even more processing here
}

protected abstract void subProcess(Object[] array);
}

public class Sub extends Super {
protected abstract void subProcess(Object[] array) {
// Do sub processing here
}
}

The abstract makes sure the Sub class has to implement a certain method
for it to compile. You can easily create different subclasses which
perform different processing:

public class OtherSub extends Super {
protected abstract void subProcess(Object[] array) {
// Do other sub processing here
}
}

public class Tester {
public static void main(String[] args) {
String[] myArray = new String[] { "a", "b", "c"};
Super one = new Sub();
Super two = new OtherSub();

one.process(myArray.clone());
two.process(myArray.clone());
}
}

I hope the examples show the power of using an abstract superclass.

Regards,

Bart

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Greg R. Broderick - 29 Jul 2006 15:15 GMT

"Mike" <mparham1@austin.rr.com> wrote in news:1154146031.584543.305470
@i3g2000cwc.googlegroups.com:

> final int Array_Length = 50;
> // Constant array size
[quoted text clipped - 13 lines]
> int index;
> // Number of array elements used

How about turning each of these arrays into an object, e.g.

public class DVD
{
     private string name;
    private long quantity;
     private BigDecimal price;
     private BigDecimal restock;

     // add getter and setter methods as appropriate
}

then you could have a single array (or better, use a List - a list can grow
or shrink) of these objects to pass back and forth.

DVD dvds[] = new DVD[ARRAY_LENGTH];

or

List dvds = new List();

Cheers
GRB

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Hendrik Maryns - 31 Jul 2006 12:00 GMT

Mike schreef:

> I am new to this and i don't understand how to transfer my arrays to a
> subclass, alter the data and then send it back to the superclass. I
[quoted text clipped - 4 lines]
>
> My superclass: Inventory is passing data to my subclass: ProductXtras.

Is ProductXtras a special case of Inventory? I don’t think so. Then do
not make it inherit from it. Rather pass the arrays explicitly to an
instance of it.

H.

- --
Hendrik Maryns

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Array to subclass

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