Re: alias for Integer

Hi all,

this is a simple question, so it may be silly...

I am processing structures that contain integers, structures such as matrixes used in statistical analysis. As I implement these as Maps of indexes, I use the class Integer, as in

  // Map<matrix index, DB index> <- I'd like to remove this comment!
  public static Map<Integer, Integer> myMap = ...;

Now what I'd like is to write
  public static Map<MatrixIndex, DbIndex> myMap = ...;

The advantage is that the code is auto-documented, but even better that the compiler will check that I never get mixed up in different indexes, by relying on strong typing.

Usually, I would do this by extending the relevant class. But here it's Integer, which is final.

Questions:
1. is this a bad good idea, and I should proceed with Integer?
2. if not, how would you implement this?
3. is there any performance issue in defining my own classes instead of Integer?

My current solution is to define my own classes for replacing Integer, such as:

public final class MatrixIndex {
  public final int value;
  public MyIndex(int i) {value = i;}
}

I won't benefit from autoboxing, then... :-(
(I'm just hoping it doesn't break too much of the code, because even though it's mine to break, I don't have infinite time)

Note that (exceptionnally for me) performance *is* an issue here. I haven't yet narrowed it down, but the code executes very slowly and eats up much too much memory at the moment. I'm starting to optimize it, that's why I'm starting with strongly typing it to prevent errors.

thanks for any tips!
JRobinss