Question

I have a set of functions defined like this:

public void foo1(int a, int b){
    if (a > b){
        c++;
    }
}


public void foo2(int a, int b){
    if (a > b && b = 7){
        c++;
    }
}


public void foo3(int a, int b){
    if (a >= b){
        c++;
    }
}

Which only differ in their conditions for a and b. Is there a way to contain these as one function, where I can set the condition as a variable? Or something similar?

EDIT: Please note this is a trivial example, I want to know if it’s possible to pass a condition to a function

Answer 1

For a general solution, you can define an interface:

public interface Predicate {
    public boolean eval(int a, int b);
}

Then define your function:

public void foo(Predicate predicate, int a, int b) {
    if (predicate.eval(a, b)) {
        c++;
    }
}

Then you can define various Predicate objects:

Predicate test1 = new Predicate() {
    @Override
    public boolean eval(int a, int b) {
        return a >= b;
    }
};
// etc.

and pass whichever one is appropriate to foo().

Alternatively, you can look at making use of the Callable interface using Boolean as the type parameter. (It can’t take arguments, however, so it doesn’t exactly fit your pattern.)