Thread: How to share variable values amongst different classes?

Hi,
I've been programming with Java for a while and am still unsure about something pretty fundamental. I am using a GUI to call methods from different classes, which works fine. However, I'm having trouble sharing the variable values from one class to another. Here is an example which I hope makes things clearer.
I have two public classes Mouse and Cat, with methods executed from a separate class for the GUI. To execute methods from the two classes I creates object in the GUI:

public Mouse eek = new Mouse();
public Cat meow = new Cat();

And then run use these to run methods. Example Mouse method = run() and Cat method = chase():

eek.run();
meow.chase();

However, the problem is I have public variables in these classes that I want to share between them. My question is: What is the best way to do this? I know

int numCheese = eek.cheese;

would get the value of cheese from Mouse and assign it to numCheese in the GUI class, but is this the best way or should I encapsulate with getter and setter methods? I want to be able to access Mouse variable values in Cat and visa-versa without having to make explicit copies in the GUI class if possible. It seems like I am going to have a lot of duplicate code in my GUI if I have to keep on copying all these variables in this way for each potential user input - there has to be a more efficient way to share variable information, right?

Hope all this makes sense, sorry for the annoying examples. Would really appreciate some advise before I start bloating my GUI code

hi ignite i hope i wont explode... hekhek joke

anyway about your problem.. it seems very hard to understand not becuase its annoying like you have said
but im not yet good in java programming,thats why, but since im getting related to what you are trying to know
ill give some of my knowledge about that,
im currently studying about defining your own classes in java and luckily that part is what am i studying right now

about sharing of variables in different classes... maybe you should declare all the variables as public first
so any objects or classes that will invoke those variables can be accesed. I defined a method and i declared public one of its variables .. and thats when I noticed that i can accessed it ..
even if i called that variable in another predefined classes that i make., in a proper way.

If you want to make all your objects accessable ofcourse you should declare it as public.
and declare it also as static so it can be accessed or called also by a "CLASS NAME" .

If those variables are from a primitive type or data type avoid using "VOID" type of return

examples: String,int.long,double.. etc...

i hop this will help you a little bit. BOOM!

Well this depends, how tight coupled do you want the class cat and mouse to be? In theory they should be as loosely coupled as possible meaning the class cat should only do its own stuff and the class mouse should do its own stuff, why would such different things need to share variables?

Second, you should most definitely use getter and setter methods, public variables is the worst way of exposing your variables data.

If you give me a layout of what you have in mind I might be able to help you out by creating a couple of samples.

// Json

Not really actually, your method there makes no real sense as all it does it deduct one from the original variable and then return it, you have effectively created a wrapper method for --variable.

You might want to still have a cheese variable on your class.

public class Rat {
 
    private int cheeseLeft;
 
    public int takeCheeseFromThePoorRat() {
        return --cheeseLeft;
    }
 
    public void giveCheeseToTheRat(final int cheese) {
        cheeseLeft += cheese;
    }
}

// Json

Thanks Json, point taken. I'm completing my first large project and although the program works fine, I have pretty much all the code in just a couple of classes with all variables and methods set as public. I've been running through a lot of tutorials and am managing to separate the methods into smaller, more logical classes and protect the variables a bit more. I know from a design point of view this should have been done from the start, but at least I'll know for next time!

You should always learn from what you are doing I believe, its the way forward

// Json