Question

I have a programming problem in Java:

Can I define a different method for any different interface array element?

myInterface[] op = new myInterface[4];

Now “myInterface” only has 1 method: public static int doSomething(int a, int b);.

I need to define that method to do different things with the numbers based on the element id (0-3).

Restrictions:

1. must use hash tables.
2. no switch-case or if statements (because of hash tables)
3. cannot under any circumstance use the Java defined hash tables

i.e. if I call op[0].doSomething(2,3) it’ll output 12 (2^2 * 3)
and if I call op[1].doSomething(2,3) it’ll output 5 (2+3).

EDIT: I’d like to know if its possible or am I chasing my tail?
if it is could someone suggest a way for it to be done, I don’t need the entire answer just suggestions, please.

P.S. Also I looked at all the pages on interfaces in Java, haven’t found anything helpful.

Answer 1

I got it.

class interface operations { public int doSomething(int a, int b) {} }

public class test {
    public static void main(...) {
    operations[] ops = new operations[4];
    ops[0] = new operations() {public int doSomething(int a, int b) {return a-b*a;}};
...etc.
}

Answer: use anonymous classes.