Making variables in a class accessible to all once changed

[int80]

I have a class that just holds values that are updated as the program receives user input. But I want this classes variables once updated to accessible to all the other classes. I can't for the life of me remember how to do that.

class1 {
variable1;
variable2;
}

class2 {
class1 class = new class1();
class.variable1 = "Java";
}

class3 {
I want to be able to change the value of class.variable1 here, and have that value remain in variable1 and be accessible to all.
}


thanks in advance.

[wsaryada]

I think you need make variable1 as a class variable, so you'll need to use the static keyword to make variable1 a class variable.

[Norm]

Also if you make the variable public, other classes will be able to see/get it.

static doesn't make a variable a class variable. static means that the variable has only one existence no matter how many instances of the class there are. If there are multiple instances of a class, a static variable would be shared by them all. If any instance changed its value, all other instances would see the change.
A class variable would exist in each class, one per class.

Make a small test program and try the different combinations to see which solves your problem.

[udayadas]

Yea, when you declare like

public static int variable;

you can access it by "Class1.variable" from anywhere.

if you do it like...

public int variable ;

then you can access it by creating object of Class1 from any where.

Class1 cc=new Class1();
cc.variable=100;

[fishtoprecords]

public static int variable;
you can access it by "Class1.variable" from anywhere.

True, but doing so is a sin. Maybe two sins.

1) It exposes all the details to the world. You can not, for example, change it from an int to a float without breaking the world.
2) global variables radically increase coupling and cohesion. The point of OO is to get software reuse by decreasing coupling and cohesion.

[udayadas]

Making variables in a class accessible to all once changed

this is what int80 wants to achive

As far as Coupling part is concerned....You cant really live without it.At best you can reduce it.Make that member private and provide setter and getter for it.Any other idea??

[int80]

Thanks alot guys! Once you use static, you obviously don't have create new instances of it either, and they become more like C structs and inter-useable (if you know what I mean), just what I wanted!

It's all starting (slowly) to fall into place now.

Also, I have one last question:

If you are in a method within a method like this:

class xxx {

 public void MethodCall(){

      public void methodcallChecker(){
>>            ///something is found to be true here, so restart methodcall()
     }
 }
}

I want to know if it's possible to restart "MethodCall()" from within methodcallChecker(), so MethodCall starts again. It's been puzzling me for ages; I tried using "this", but that doesn't work.

Again, thanks in advance.

[Fubarable]

does your "method within a method" code even compile? Please try that and get back to us with your result.

[int80]

Ok, I get what you're saying...

class xxx {

 public void MethodCall(){

  class xxxx {
      public void methodcallChecker(){
>>            ///something is found to be true here, so restart methodcall()
     }
  }
 }
}

I mean like that.

[udayadas]

He..He.. I belive....java does not allow this

[Norm]

java does not allow this

Not allow what?
The test would be to see if it compiles?

so restart methodcall()

What does that mean? Would the Checker method throw an exception that would bubble up to the caller of the method MethodCall?

[int80]

I'm pretty confused to tell you the truth.

class xxx {
 public void MethodCall(){

  final class xxxx {
      public void methodcallChecker(){
>>            ///something is found to be true here, so restart methodcall()
     }
  }
 }
}

MethodCall() is called from the main() class, so maybe I could call it in a for( ;; ) loop, and return back to the main class once methodcallChecker has found something to be true. Then it'll keep getting called anew?

It's weird, I've actually managed to write a reporting engine for a MySQL database, but just get stuck on these weird little problems. I've got gaping holes in my Java knowledge that seriously hinder me. I really need to get reading.

[udayadas]

Java does not allow nested methods.

On the other hand method local inner classes are allowed

[Norm]

You need to explain how/why the various methods are being called.
Get a design before coding is always a good rule.