protected static boolean isQualifierInProject(@NotNull String classFQN, @NotNull Project project) {
    JavaPsiFacade psiFacade = JavaPsiFacade.getInstance(project);
    PsiManager psiManager = PsiManager.getInstance(project);

    String qualifierText = StringUtil.getPackageName(classFQN);
    PsiClass outerClass = psiFacade.findClass(qualifierText, GlobalSearchScope.projectScope(project));
    if (outerClass != null) {
      return psiManager.isInProject(outerClass);
    }
    for (; !StringUtil.isEmpty(qualifierText); qualifierText = StringUtil.getPackageName(qualifierText)) {
      PsiPackage psiPackage = psiFacade.findPackage(qualifierText);
      if (psiPackage != null) {
        return psiManager.isInProject(psiPackage);
      }
    }
    return false;
  }
protected static boolean isQualifierInProject(@NotNull String classFQN, @NotNull Project project)