code: public void setAllowOrigin(String... origin) {
          allowOriginSet.clear();
          allowOriginSet.addAll(Arrays.asList(origin));
          allowOrigin = Joiner.on(",").join(origin);
      }
docs: Set the list of request origins that are permitted to access the protected routes.
  
  Multiple origins may be specified and they must be complete scheme, domain, & port
  specifications.  Alternatively, you can specify the wildcard origin "*" to accept
  from all origins.
  
  setAllowOrigin("*");
  setAllowOrigin("http://mydomain.com:8080", http://myotherdomain.com:8080");
  
  @param origin