JavaGen

JavaGen is a simple example external plugin for the -generate instruction. It takes a set of input files, preprocesses them, and places them in the output directory. Although this works for any syntax, the primary idea was to generate Java files using the bnd preprocessor, and the build properties as the template information domain.

The javagen command takes the following command line:

javagen [-o dir] FILESET...

For example, the following line will read .java files from the input/ directory and pre-process each file to the src-gen/ directory.

javagen -o src-gen input/**.java

The output file will be placed in the directory, relative to src-gen, as specified in the package, even if the input file is in another directory. This is only done when the outout contains a package statement. The src-gen directory should be place on the src path for bnd, you can do this in the bnd.bnd file with:

src = ${^src},src-gen

Input Format

The input files must have the same name as the output file name. However, an input file can start with a header. A header is signalled with the --- characters. The text between the --- and next --- (on its own line) is treated as properties in the bnd format. You can use the -include instruction to include other properties and handling of the ./ is similar. These properties inherit from the project (and thus cnf/build.bnd) and will override them.

For example:

---
foo=1
-include foo.bnd
---
package foo.bar;

public class Foo {
    public static int foo = ${foo};
    
    public static String[] BUILDPATH = {
        ${template;-buildpath;"${@}"}
    };
}