Global variables...

[Tris Rabar]

Hi there,
I have an application that comprises several classes, and one main one. In one class I'm initialzing an array, whose values I want to alter in another class. How do I make this array available to all ... delcare as static in the main class...I want it as a 'global' variable?

[Michael Morris]

Hi Tris,
Before I respond, let me try to convince you that there is rarely any justification for "globalizing" an array. You can take this from someone who has many extra gray hairs due to dealing with global variables over the past 30 years. If you must access the array directly by another class I would suggest that you change your design and do it with an inner class. If you must have separate classes then at least give the array default (or package-private) access. As for whether it should be static or not, that depends on whether you just want one array or an array for every instance of the class. Assuming the former to make the array accessible to all classes in the package do this:

  static MyArrayClass[] array;

Now if you decide to access it inside an inner class then you should declare it thus:

  private static MyArrayClass[] array;

You should also consider giving access to external classes with a getter:

  public MyArrayClass[] getArray();

Hope this helps
Michael Morris
SCJP

[Bear Bibeault]

Listen to Michael for he is wise. If you find that you need a "global" variable, it's almost always a clue that your design is not correct for the problem you are trying to solve.
The simplest solution might be to simply pass a reference to the array to your method. And as Michael pointed out, there are other mechanisms available for more complex situations.
hth,
bear

[Tris Rabar]

Hey...
Thanks for the help! I will look at my design again and try to implement this without having to globalize the array.
Thanks a lot!