Preprocessor definitions

[CuddlyKittens11]

Hey, I'm an avid C/C++ programmer, and I love my "#define" preprocessor macro. But I heard that java doesn't have anything like it?

Anyone know a work-around?

[sunde887]

I don't know preprocessor macro's too well in c/c++, but what are you looking to simulate with a java-like macro?

Others with better c++ knowledge however; may be able to give much better advice.

[CuddlyKittens11]

I'm looking to create some sort of global variables essentially.

A quick explanation of how #define works is that you have it in your code, like this:

#define MEANING_TO_LIFE 42

// Later on in your code
if (21 * 2 == MEANING_TO_LIFE) {
    // More code here

What the preprocessor actually does is search all your code for the #define, and replaces it, so the example above, when shipped off to the compiler, is actually:

// Later on in your code
if (21 * 2 == 42) {
    // More code here

As I said, I'm just looking for a method of having some global variables throughout my whole java program.

[DarrylBurke]

In Java there isn't such a beast as a global variable. I think what you're looking for is static final variables, which the compiler treats as compile-time constants and substitutes the value wherever the constant is used. Oversimplified example:

public class A {

  static final String NAME = "Class A";
}

public class B {

  public B(String name) {
    if (name.contains(A.NAME)) {
      System.out.println("parameter to constructor contains " + A.NAME);
    }
  }
}

When compiling class B, the constant value "Class A" will be substituted in place of A.NAME.

Note that any subsequent change to the value of the constant in the code of class A will not be propagated to class B until both A and B are recompiled.

db

[CuddlyKittens11]

Okay, thank you, that helps a lot.