Based on Wikipedia example for Delegation Pattern the following sample code is offered. But I also have my version of code, that just have minor changes. I want to know which code is better/(more flexible) and why?
Thank you in advance.
Wikipedia Code
interface I {
void f();
void g();
}
class A implements I {
public void f() { System.out.println("A: doing f()"); }
public void g() { System.out.println("A: doing g()"); }
}
class B implements I {
public void f() { System.out.println("B: doing f()"); }
public void g() { System.out.println("B: doing g()"); }
}
class C implements I {
I i = null;
// delegation
public C(I i){ this.i = i; }
public void f() { i.f(); }
public void g() { i.g(); }
// normal attributes
public void to(I i) { this.i = i; }
}
public class Main {
public static void main(String[] args) {
C c = new C(new A());
c.f(); // output: A: doing f()
c.g(); // output: A: doing g()
c.to(new B());
c.f(); // output: B: doing f()
c.g(); // output: B: doing g()
}
}
My Code (all classes are the same)
public class Main {
public static void main(String[] args) {
//C c = new C(new A());
I ii = new A();
ii.f(); // output: A: doing f()
ii.g(); // output: A: doing g()
//c.to(new B());
ii = new B();
ii.f(); // output: B: doing f()
ii.g(); // output: B: doing g()
}
}
Your code is not using the delegation pattern at all, you're just calling the methods on the implementing classes directly.