Thingworx custom Authenticator extension not working

I am trying to customise the Thingworx authentication flow by developing Authenticator extension .

I am trying to login into Thingworx by hitting url like <http://localhost:8080/Thingworx/Home?username="Administrator">   instead of login through Thingworx login page. But when i hit this url , i am getting error as "com.thingworx.common.exceptions.InvalidRequestException: Authentication failed: Please make sure the credentials are correct." in application logs.

Below is my code of "authenticate" method of my Authenticator extension:

@Override

public void authenticate(HttpServletRequest httpRequest, HttpServletResponse httpResponse)

throws AuthenticatorException {

     try {

          String user= httpRequest.getParameter("username");

          AuthenticationUtilities.validateEnabledThingworxUser(user);

          this.setCredentials(user);

          } catch (Exception e) {

               this.setRequiresChallenge(false);

               throw new AuthenticatorException("Provided username is not valid, " + ADICognitoAuthenticator.class.getSimpleName() + " failed to auto login!");

          }

}

Is it possible to login into Thingworx without giving password via custom Authenticator extension?