to extend or not

[-]

which is the preferred style?

public class App {

private JFrame frame;

public App() {
frame = new JFrame();
}
}

or

public class AppFrame extends JFrame {

public AppFrame() {
}
}

 

[R.F. Pels]

public class App {

private JFrame frame;

public class AppFrame extends JFrame {

Those two are not the same. You really need to read a book on Object
Oriented Programming.

 

[Peter Kirk]

Those two are not the same. You really need to read a book on Object
Oriented Programming.

It's hard to know whether or not "-" knows that these are not equivalent. My
guess is that he does know they are different, and is asking "what is
'best'" - that is, composition or inheritance.

I don't have a definitive answer, but there are plenty of hits on Google
when searching for "java composition inheritance".

Peter

 

[Ulf_N]

- skrev:

which is the preferred style?

public class App {

private JFrame frame;

public App() {
frame = new JFrame();
}
}

or

public class AppFrame extends JFrame {

public AppFrame() {
}
}

Ask yourself: Is your class first and foremost a JFrame (your own
version of a JFrame, overriding JFrame methods etc.), or does your class
just happen to use a JFrame (as a gui window, for instance)? In most
cases you probably use JFrame (composition) rather than modify it
(inheritance). It all depends on what your class is and does... /ulf