private Element getOrLoadVCard(String username) {
        Element vCardElement = vcardCache.get(username);
        if (vCardElement == null) {
            vCardElement = provider.loadVCard(username);
            if (vCardElement != null) {
                vcardCache.put(username, (DefaultElement) vCardElement);
            }
        }
        return vCardElement;
    }
Returns the vCard of a given user or null if none was defined before. Changes to the
returned vCard will not be stored in the database. Use the returned vCard as a
read-only vCard.

@param username Username (not full JID) whose vCard to retrieve.
@return the vCard of a given user.
xmppserver/src/main/java/org/jivesoftware/openfire/vcard/VCardManager.java