[doomer999]

Hi,

In the documentation "Efficient MIDP programming", it is mentioned that using "source-code preprocessor" is better than "static final" variables. What exactly is it? How to use it?

Thank you
Nelson

[mcmcdonald]

I am interesting too in using a preprocessor integrated in wtk,...

McMc

[akokchai]

Hi,

What I guess is like that:

If our MIDP suite has 2 files A and B. Inside A, we define 5 "static final" constant, inside B, we define 4 "static final". The 6 "static final" must "eat" some spaces in the .jar.

How abt we create another class C? This class is ONLY used to define constants and we can move the 9 variables to C. After compiled, constants in A and B will be all replaced by the actual values from C. And then, we can remove C since C is useless in the suite. This way can save the spaces for defining constants in the A and B.

I hope I don't mistake the meaning.. :)

Good lucks.

[mcmcdonald]

Hi!

Good idea !

Thanks
McMc

[grahamhughes]

That's right... static final members are expensive on space. A pre-processor is used by C compilers to process the source code before the compiler sees it. You will see directives in C programs like:

#define MAX_ARRAY_SIZE 256

which defines a constant. The compiler itself never sees this... this directive tells the pre-processor to replace every occurance of the text "MAX_ARRAY_SIZE" within the source code with the text "256". So the source code reads:

char ach [MAX_ARRAY_SIZE];

but the compiler sees:

char ach [256];

(The pre-processor has enough of an understanding of C not to replace text in double-quotes, for example).

So in a C program, there is no difference between a symbolic-constant (one with a name) and a literal-constant (one that just has a value).

C and Java are sufficiently similar that you can get away with using a C pre-processor with a Java program. You'd need to add an appropriate command to your 'make' routine. Using the pre-processor from the GNU C compiler, that would be something like:

cpp -P -nostdinc -undef MyClass.java

You can also make use of other feature of the pre-processor, like conditional compilation, which allows you to include extra sections of code for a "debug build", or exclude them from a "production build".

Graham.