private boolean canExtractEnum() {
    final List<PsiField> fields = new ArrayList<>();
    final List<PsiClass> innerClasses = new ArrayList<>();
    final List<PsiMethod> methods = new ArrayList<>();
    for (MemberInfo info : memberInfo) {
      if (info.isChecked()) {
        final PsiMember member = info.getMember();
        if (member instanceof PsiField) {
          fields.add((PsiField)member);
        }
        else if (member instanceof PsiMethod) {
          methods.add((PsiMethod)member);
        }
        else if (member instanceof PsiClass) {
          innerClasses.add((PsiClass)member);
        }
      }
    }
    return !new BackpointerUsageVisitor(fields, innerClasses, methods, sourceClass).backpointerRequired();
  }
private boolean canExtractEnum()