Metacat

     *  Method used to log in to a metacat server. Implementations will need

     *  to cache a cookie value to make the session persistent.  Each time a

     *  call is made to one of the other methods (e.g., read), the cookie will

     *  need to be passed back to the metacat server along with the request.

     *

     *  @param username   the username of the user, like an LDAP DN

     *  @param password   the password for that user for authentication

     *  @return the response string from metacat in XML format

     *  @throws MetacatAuthException when the username/password could

     *                    not be authenticated

     */

    public String validateSession(String sessionId)

    		throws MetacatAuthException, MetacatInaccessibleException {

        Properties prop = new Properties();

        prop.put("action", "validatesession");

        prop.put("sessionid", sessionId);

        String response = null;

        try {

            response = sendDataForString(prop, null, null, 0);

        } catch (Exception e) {

            throw new MetacatInaccessibleException(e.getMessage());

        }

        if (response.indexOf("<validateSession><status>") == -1) {

            setSessionId("");

            throw new MetacatAuthException(response);

        } 

        return response;

    }

    /**