Consider two designs. (Basically one uses inheritance to reuse functionality fro

ID: 3677834 • Letter: C

Question

Consider two designs. (Basically one uses inheritance to reuse functionality from A and the other uses composition.)

************** Design 1 **************

public class A {
void f() {
. . .
}
}

public class B extends A {
public void f() {
super.f();
... new feature/behavior ...
}
}

************** Design 2 **************

public class A {
void f() {
. . .
}
}

public class B {
private A a;
public B(A a) {
this.a = a;
}

public void f() {
a.f();
... new feature/behavior ...
}
}

Which design has more coupling between A and B?

Design 1 has more coupling than design 2

Design 2 has more coupling than design 1

Both designs have the same coupling

It's impossible to tell without knowing the dynamic behavior

Design 1 has more coupling than design 2

Design 2 has more coupling than design 1

Both designs have the same coupling

It's impossible to tell without knowing the dynamic behavior

Design 1 has more coupling than design 2

Inheritance is strongly coupled whereas composition is loosely coupled

Inheritance will bring you tight coupling, simply one change to base class can break many child classes.

Inheritance is compile time determined whereas composition is run-time

When compiled, your base class codes will be added to every child class.

Inheritance breaks encapsulation whereas composition does not

This is the reason why often composition is preferred to inheritance

Use inheritance only when all of the following criteria are satisfied (Coad's Rule):