How to avoid PreResultListener called twice in action chaining

[JOSE L MARTINEZ-AVIAL]

Hello all,
  I've developed an interceptor to add cookies to the response. It works as
follows:
[..]
    public String intercept(ActionInvocation invocation) throws Exception {
        invocation.addPreResultListener(this);
        return invocation.invoke();
    }

  public void beforeResult(ActionInvocation invocation, String resultCode) {
        //log.debug("beforeResult start");
        ActionContext ac = invocation.getInvocationContext();
        HttpServletResponse response = (HttpServletResponse)
ac.get(StrutsStatics.HTTP_RESPONSE);
        addCookiesToResponse(invocation.getAction(), response);
        //log.debug("beforeResult end");
    }
    private void addCookiesToResponse(Object action, HttpServletResponse
response) {
        //log.info("CookieProviderInterceptor "+action);
        if (action instanceof CookieProvider) {


            Map<String,CookieBean> cookies = ((CookieProvider)
action).getCookies();
            //log.info("CookieProviderInterceptor "+cookies);

            if (cookies != null) {
                Set<Entry<String,CookieBean>> cookieSet =
cookies.entrySet();
                for (Entry<String, CookieBean> entry : cookieSet) {
                    CookieBean cookiebean = entry.getValue();
                    Cookie cookie = new Cookie(cookiebean.getCookieName(),
cookiebean.getCookieValue());
                    cookie.setMaxAge(cookiebean.getMaxAge());
                    cookie.setComment(cookiebean.getComment());
                    if (cookiebean.getDomain()!=null)
                        cookie.setDomain(cookiebean.getDomain());
                    cookie.setPath(cookiebean.getPath());
                    cookie.setSecure(cookiebean.getSecure());
                    cookie.setVersion(cookiebean.getVersion());
                    //log.info("adding "+cookie);
                    response.addCookie(cookie);
                }
            }
        }
    }

So the idea is that the Action implements CookieProvider, returning a map of
cookies, and put the cookies in the response. It works well, but I'm having
some problems when I chain two actions, if both of them are CookieProvider,
and both return a cookie with the same name. My idea was be that the first
cookie would be overwritten by the second one, but in fact the response has
both cookies, with the same name. After giving it a thought, it makes sense,
so probably I'm doing something wrong. Any insight on how to do this?

TIA

Jose Luis