public Iterable<? extends JavaFileObject> getJavaFileObjectsFromFiles(
        Iterable<? extends File> files)
    {
        ArrayList<RegularFileObject> result;
        if (files instanceof Collection<?>)
            result = new ArrayList<RegularFileObject>(((Collection<?>)files).size());
        else
            result = new ArrayList<RegularFileObject>();
        for (File f: files)
            result.add(new RegularFileObject(this, nullCheck(f)));
        return result;
    }