code: private void addSourceRoot (final File directory)
    {
      if (this.project != null)
      {
        getLog ().debug ("Adding compile source root: " + directory);
        this.project.addCompileSourceRoot (directory.getAbsolutePath ());
      }
    }
docs: Registers the specified directory as a compile source root for the current
  project.
  
  @param directory
  The absolute path to the source root, must not be <code>null</code>.