code: public void setTokenValue(String tokenName, Cookie value) {
  		if (value == null) {
  			tokenValues.remove(tokenName);
  		} else {
  			tokenValues.put(tokenName, value);
  		}
  	}
docs: Sets a particular value for a session token. If the value is null, that token is deleted from
  the session.
  
  @param tokenName the token name
  @param value the new value of the token, or null, if the token has to be deleted