Simulating Pointers in Java...

Posted on 2005-03-24
Medium Priority
Last Modified: 2012-06-27
Ok, this is a relatively simple question from a C++ addict that's spent far too long cussing at Java for not being quite so flexible as C/C++ when it comes to pointers etc. So, I'm basically asking what would be the 'standard JAVA method' of overcoming this problem...

I have my class (PendulatorFrame) which contains details of the main window frame, and in this class, is another class which stores information about a dynamical system (PendulatorSystem). I then want to have 2 other classes in PendulatorFrame that are 'viewports' for the dynamical system. However, I need these viewports (which extend Component) to access the PendulatorSystem that lives in PendulatorFrame directly. I would normally do this in C++ by storing a pointer to PendulatorSystem in PendulatorViewport2D and PendulatorViewport3D, but obviously, Java doesn't understand pointers, and I believe that if I were to have an instance of PendulatorSystem defined in PendulatorViewport2D and set that 'equal' to the one in PendulatorFrame when it's constructed - it will merely be another instance which starts off the same (and so, when the one in PendulatorFrame advances, the one in PendulatorViewport2D DOESN'T).

If someone could clarify the 'standard Java way' of handling this lack of pointers, that would be greatly appreaciated.
Question by:Telumehtar
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LVL 92

Accepted Solution

objects earned 600 total points
ID: 13625545
> it will merely be another instance which starts off the same

that is not correct, both vars will point to the same instance (as u require)

Author Comment

ID: 13625597
Really - So Java doesn't pass values, but a reference?

So I could pass the same PendulatorSystem to a completely seperate class (buttonListenerHandler) and it would also be able to directly access this variable?

Author Comment

ID: 13625665
Would you believe it - you're right. It's easy points day for objects today!

Sorry for the stupid question, I just didn't want to mess up the 500+ lines of code I have by putting in a whole bunch of new prefixes to all the variables if it wasn't going to work.

Many thanks!
LVL 92

Expert Comment

ID: 13625691

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