code: public static void generate(ConfigurationImpl configuration,
                                  ClassUseMapper mapper, PackageDoc pkgdoc) {
          PackageUseWriter pkgusegen;
          DocPath filename = DocPaths.PACKAGE_USE;
          try {
              pkgusegen = new PackageUseWriter(configuration,
                                               mapper, filename, pkgdoc);
              pkgusegen.generatePackageUseFile();
              pkgusegen.close();
          } catch (IOException exc) {
              configuration.standardmessage.error(
                  "doclet.exception_encountered",
                  exc.toString(), filename);
              throw new DocletAbortException(exc);
          }
      }
docs: Generate a class page.
  
  @param configuration the current configuration of the doclet.
  @param mapper        the mapping of the class usage.
  @param pkgdoc        the package doc being documented.