🚀 go-pugleaf

You can do it like this :

processObject(Object obj)
{
    if (obj instanceof A) {
       A objA= (A)obj;
        objA.writeA();
    }
    else
    {
        if (obj instanceof  B){
       B objB= (B)obj;
        objB.writeB();        }
        else
        {
           .....
        }
    }
}


but I would consider it a better design to have a common base class (or an interface) X for A, B, C .
Define in X a method write() and override it (or implement -if X is an interface)
in A,B,C with the same functions writeA, writeB, etc.

Then you can rewrite the function to

processObject(Object obj) {

   if (obj instanceof X) obj.write()
   else {
       extra processing for obj;
    }
}

Heikel schrieb:

> Hi,
>
> I ve the following problem:
>
> I have:
>      3 Classes: "A", "B" and "C"
>      1 Method: "processObject(Object obj)"
>
> "obj" may be from type "A", "B" or "C" .
>
> processObject(Object obj)
> {
>     if (obj from type A)
>         obj.writeA();
>     else
>     {
>         if (obj from type B)
>             obj.writeB();
>         else
>         {
>             if (obj from type C)
>                 obj.writeB();
>             else
>             {
>                 extra processing for obj;
>             }
>         }
>     }
> }
>
> How can I use the specific methods (writeA(), writeB(), writeC()) ?
> How should I change the code of "processObject(Object obj)"?
>
> Thank you
> H. Jrad :-)