Tracking changes in some central database by multiple objects scattered around the program

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jb - 03 Jun 2006 12:04 GMT

Hi!
I've been writing a program that operates on small hand-made database.
And I would like other objects to track changes in this database
possibly in the swing way i.e:
class DataBase {
public void addActionListner(ActionListener foo){
//* What to put here *//
}

public void changePartOfDatabase{
/*....*/
fireActionPerformed();
}
}

Other objects interested in tracking changes would just add new
Listener.

I suspect that there is a class from I could inherit such functions -
but I hadn't been able to find it. ;-(. If there is please drop me some
keywords so I could google for it, if there is not please tell me how
to write such a thing by myself.

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Andrew McDonagh - 03 Jun 2006 12:11 GMT

> Hi!
> I've been writing a program that operates on small hand-made database.
> And I would like other objects to track changes in this database
> possibly in the swing way i.e:

class DataBase {
private List listeners =new ArrayList();

public void addActionListner(ActionListener foo){
listeners.put(foo);
}

public void changePartOfDatabase{
fireActionPerformed();
}

private void fireActionPerformed() {
for (int index = 0; index < listeners.length(); index++) {
ActionListener listener = (ActionListener)listeners.get(index);
listener.actionPerformed();
}
}

}

> Other objects interested in tracking changes would just add new
> Listener.
[quoted text clipped - 3 lines]
> keywords so I could google for it, if there is not please tell me how
> to write such a thing by myself.

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Tracking changes in some central database by multiple objects scattered around the program

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