C2J, a C++ to Java translator

c2j is a C++ to Java translator that translates C++ code to Java code. The parser is written in C++, because I wrote it before I ever heard of Java... The input to c2j must consist of:

one .H file, containing one or more C++ class definitions.
one .C file, containing all method bodies referenced in the .H file.

c2j is basically a shell-script that calls sed, a C++-to-Java translator, and the C pre-processor to do all the weaving of moving methods into one Java class definition.

This parser currently uses a shell script and a Unix utility called "sed". When you have access to Unix utilities on a Windows PC (like the MKS toolkit), the parser could also be used.

On UNIX, and Win95/WinNT use the following command to make the parser:

	make

Different problems that are tackled by this parser:

C++ can have a header file with a class declaration and a member function given in another file (typically a .C or .cpp file), Java has all the methods "inlined" in the class definition.
Data types are incompatible (unsigned versus int, for instance)
Pointer references (->) need to be translated into refs (.)
Access (public,protected,private) is done by region in C++, and is per method in Java.
Print statements to cerr and cout, which are to be translated into calls to System.out.print, and System.err.print.
Statements with "delete object;" need to be translated into "object = null;" to render a similar effect. Note that these assignments are not necessary at all in a destructor, as we will lose the reference to the object automatically.
Overloaded operators in a class definition are meaningless in Java.
C++ has multiple inheritance. Java has single inheritance and interfaces. In the case of multiple inheritance, we need to make a decision.

Variable declarations on the stack are not recognized and handled.
Overloaded operators in the code.
pointer artithmetic.
Templates.
Global variables are collected and put into the first class found in the .H file. Something goes wrong during collection or writing, and this class might not be the right location after all.
Sometimes the parser has problems with method parameters (especially with constructors). Keep the .H and .C file handy...
Documentation (no time...)

c2j translates roughly about 85-95 percent of our code correctly. It saves me a lot of editing time (inlining all methods, translating simple types, removing &'s everywhere, changing -> into ., etc. Just run it and see what it does for you...

A beta version of c2j can be downloaded here for free.

We have decided to put this parser in the public domain. Use it at your own risk, and if you make any changes (especially improvements), tell us! We hope that this utility is useful for you and the rest of the C++/Java community.

Chris Laffra
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Morgan Stanley, 750 Seventh Avenue (between 49 & 50), NYC, NY 10019
Email: laffra@ms.com, Tel: (212) 762 2223, Fax: (212) 762 0520
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