I ran into a problem a few days ago when I had to introduce C++ files into a Java project. It started with a need to measure the CPU usage of the Java process and it was decided that the way to go was to use JNI to call out to a native library (a shared library on a Unix machine) written in C. The problem was to find an appropriate place to put the C files in the source repository (incidentally Clearcase) which consists of only Java files.
I thought of a couple of alternatives:
(a) Create a separate directory for putting the C files (specifically, one .h file and one .c file) at the top of the source base like:
/vobs/myproduct/javasrc /vobs/myproduct/cppsrc
I didn't like this because I have only two C files and it seemed very odd to split the source base at the language level like this. Had substantial portions of the project been written more or less equally in C++ and Java, this could be okay.
(b) Put the C files into the Java package that uses it.
I have the calling Java classes in /vobs/myproduct/com/mycompany/myproduct/util/ and the C files also go in there.
I didn't like this either because I think the C files just don't belong in the Java package.
Has anybody solved a problem like this before? Generally, what's a good strategy to follow when organizing codebase that mixes two or more languages?
Update: I don't have any plan to use any C or C++ in my project, some Jython perhaps, but you never know when my customers need a feature that can be solved only by using C or best solved by using C.
"I didn't like this because I have only two C files and it seemed very odd to split the source base at the language level like this"
Why does it seem odd? Consider this project:
project1\src\java project1\src\cpp project1\src\python
Or, if you decide to split things up into modules:
project1\module1\src\java project1\module1\src\cpp project1\module2\src\java project1\module2\src\python
I guess it's a matter of personal taste, but the above structure is fairly common, and I think it works quite well once you get used to it.