Extend Graphics OBJECT

Question

Hi!
I need to add functionality to existing Graphics objects, like in:
interface ABC {
  public void drawString(String,int,int);
  public void m();
class ABCGr extends Graphics implements ABC {
  public void m() {}
class Sth extends JPanel {
  public void doSth(ABC d) {}
  public void paintComponent(Graphics g) {
    ABC d = (ABCGr)g;
    doSth(d);
}(This does not run, of course.)
The crucial point here is that doSth() is also called with something else than an extended Graphics object (i.e. another ABC).
Is the only way to achieve this to write a wrapper that contains a reference to the Graphics object and wraps all Graphics methods explicitely? This would be a bit clumsy!
Any hint to a more elegant (and probably better performing) way would be greatly appreciated!
Best regards,

Answer 1

As much as I hate to say it, you really can't extend the graphics object.
Here's why, basically the graphics object is supposed to be an interface to a canvas so it sit right on top of the thing that you are drawing to, be that the screen, an image in memory or the printer. SO you really can't extend it. You'd have to extend every seperate instance.
What it sounds like you want to do is provide a bunch of utility functions to the Graphics object. This is probably better done with a class of static functions like this.
class GraphicsUtil {
static void doGraphicsFun( Graphics g) {//do stuff
}I know that it's not the most elegant solution, but the graphics class is an abstract class and you can't really add functionality like that. Think about extending an interface, if you extend an interface, you can't make all the classes that implemented the old interface implment your new functions.
I wouldn't write a wrapper, this will only slow your code down, static functions are the way to go.