ParserExtension and Custom Renderer components

Question

Hi,
I am trying to create a custom component of my own which will control access to UINodes based on the contents of the User's HTTPSession object. In the HTTPSession I have a list of Roles that are assigned to the user and based on these roles I would like to turn on/off certain UI nodes. Initially I tried to create a component that was defined like this:
<sso:ssoassetchecker asset="987654321">
<contents>
<messageBox automatic="true"/>
</contents>
</sso:ssoassetchecker>However I was having trouble (probably due to me needing to have the contents tag in there but no having child node support in my custom UINode).
So I decided to look at the ParserExtension mechanism to get a component that looked like this:
<link text="User List (Super)" destination="UserList-SuperAdmin.uix" sso:assetcheck="sso_super_admin_role"/>This almost worked but I think that the ParserExtension will not operate dynamically for each user. I have some code in the ParserExtension that looks like this:
public Object elementEnded(ParseContext context, String namespaceURI, String localName, Object parsed, Dictionary attributes)
    logger.debug("::elementEnded - About to parse new attribute type");
    if (parsed instanceof MutableUINode)
      MutableUINode node = (MutableUINode)parsed;
      Object assetId = attributes.get("assetcheck");
      if (assetId != null)
        List roleIdsToCheck = new LinkedList();
        StringTokenizer strTok = new StringTokenizer((String)assetId, ":");
        logger.debug("::elementEnded - Checking whether user has any of the roles : " + assetId + " for node " + node.getNodeID());
        while (strTok.hasMoreTokens())
          roleIdsToCheck.add(strTok.nextToken());
        BajaContext bajaContext = BajaParseContext.getBajaContext(context);
        HttpServletRequest request = bajaContext.getServletRequest();
        UserInfo userInfo = SSOManager.getUserInfo(request);
        boolean roleFound = false;
        if (null != userInfo)
          String username = userInfo.getUsername();
          long userId  = userInfo.getUserId();
          logger.debug("::elementEnded - Getting ROLES for username : " + userInfo);
          Iterator rolesToCheckIterator = roleIdsToCheck.iterator();
          while ( (rolesToCheckIterator.hasNext()) && (!roleFound) )
            String curRoleToCheck = (String)rolesToCheckIterator.next();
            logger.debug("::elementEnded - Checking whether user has current role : " + curRoleToCheck);
            if (userInfo.checkPermissionForRole(curRoleToCheck))
              roleFound = true;
              logger.debug("::elementEnded - MATCH User does have current role : " + curRoleToCheck);
          if (!roleFound)
            logger.debug("::elementEnded - No match found for specified roles - HIDING node");
            node.setAttributeValue(UIConstants.RENDERED_ATTR, "false");
            parsed = null;   
    else
      logWarning(context, "Controller extensions not supported on " + parsed + " objects");
    return parsed;
}I know it is a bit hacky at the moment just turning off the rendered attribute and returning null but I just want to get it going.
So, after all that the question is this : will this ParserExtension get called each time the page is rendered and correctly get the data from the user's httpsession OR will the session only be looked up the first time the page is rendered?
Many thanks,
pj.

Answer 1

The page should only be parsed once (and when the file is modified). It seems like if you're only trying to turn on and off certain ui nodes you should be able to write a template...