JAX-WS WebMethods authorization code duplicates

Question

I have a number of WebMethods using JAX-WS and every method should be authenticated using client certificate. Therefore I need to read DN from client certificate and other information which should be used in authorisation process.

The sample method looks like this:

    @WebMethod
    public String sampleMethod(
            @XmlElement(required = true)
                @WebParam(name="attribute") String one,
            @XmlElement(required = true)
                @WebParam(name="attribute2") String two) throws Exception {
        String message = null;
        String clientDN = getClientDN();

        if (isAuthorized(clientDN)) {
            // Do something
        }

        return message;
    }

    @WebMethod
    public String sampleMethod2(
            @XmlElement(required = true)
                @WebParam(name="attribute") String one,
            @XmlElement(required = true)
                @WebParam(name="attribute2") String two) throws Exception {
        String message = null;
        String clientDN = getClientDN();

        if (isAuthorized(clientDN)) {
            // Do something
        }

        return message;
    }

    private String getClientDN() {
        HttpsExchange exchange = (HttpsExchange) context.getMessageContext().get(HTTPS_EXCHANGE);
        SSLSession sslsession = exchange.getSSLSession();
        try {
            String name = sslsession.getPeerPrincipal().getName();
            log.debug("client DN: " + name);
            return name;
        } catch (SSLPeerUnverifiedException e) {
            e.printStackTrace();
        }
        return null;
    }

So in this case I need to get client certificate DN in every WebMethod defined and this duplicates the code.

I was looking into handler classes but I don't see a way how to do it with it because the handler is basically independent from service class.

Is there a way how to do authorisation globally for the whole web service? Also I would need to pass client DN into service after successful authorisation to work with it.