Classes and Components Question

[mfalomir]

Hi, I have Class A (extends Applet btw), where I declare a TextArea that I use for tracing results, and Class B where I define some methods, and that it's used by Class A. Is it possible to use the same trace textArea withing Class B ? So that I can trace some results or Exceptions that methods within class B could possibly throw, in the same trace textArea ?

Thanks in advanced

 

[Diancecht]

Yes, it's possible, and there are a few ways to do that.

One simple way is passing a reference of class A to class B so class B can acces the TextArea.

Cheers,

Dian

 

[Bong]

I think it will work if you make the TextArea a field of Class A. Then, so long as your application instantiates a Class A object, say CA, then Class B can refer to CA.<TextAreaName>.

I'm fairly inexperienced but I think that will work.

_________________
Bob Rashkin
rrashkin@csc.com

 

[mfalomir]

Hi Dian, thanks for your reply If a have an abstract class and cannot instantiated it like

myAbsClass newObj = new myAbsClass ( trace );

how can I pass the trace by reference to it ?

Thanks!

 

[timw]

Why is myAbsClass (which should be capitalised by convention, BTW) abstract, then?

Anyway, you shouldn't expose the things in a class to direct outside influence. That increases coupling. If Class B used the TextArea member of Class A directly, then it becomes more difficult to update the behaviour of Class A in the future. Have a method, such as trace(String message), in Class A. How Class A applies this is encapsulated within itself. If you want to update this later, perhaps writing the trace text to some other resource, you can simply make the change in Class A without affecting other Classes cos these just go through the trace method as usual.

Tim
---------------------------
"Your morbid fear of losing,
destroys the lives you're using." - Ozzy