public void addUrl(@NotNull String url, @NotNull String userName) {
    for (UrlAndUserName visitedUrl : myState.visitedUrls) {
      if (visitedUrl.url.equalsIgnoreCase(url)) {  // don't add multiple entries for a single url
        if (!userName.isEmpty()) {                 // rewrite username, unless no username is specified
          visitedUrl.userName = userName;
        }
        return;
      }
    }

    UrlAndUserName urlAndUserName = new UrlAndUserName();
    urlAndUserName.url = url;
    urlAndUserName.userName = userName;
    myState.visitedUrls.add(urlAndUserName);
  }
public void addUrl(@NotNull String url, @NotNull String userName)