JAXL::handle_iq PHP Method

    public function handle_iq($stanza)
    {
        $stanza = new XMPPStanza($stanza);
        // emit callback registered on stanza id's
        $emited = false;
        if ($stanza->id && $this->ev->exists('on_stanza_id_' . $stanza->id)) {
            //JAXLLogger::debug("on stanza id callbackd");
            $emited = true;
            $this->ev->emit('on_stanza_id_' . $stanza->id, array($stanza));
        }
        // catch roster list
        if ($stanza->type == 'result' && ($query = $stanza->exists('query', 'jabber:iq:roster'))) {
            foreach ($query->children as $child) {
                if ($child->name == 'item') {
                    $jid = $child->attrs['jid'];
                    $subscription = $child->attrs['subscription'];
                    $groups = array();
                    foreach ($child->children as $group) {
                        if ($group->name == 'group') {
                            $groups[] = $group->text;
                        }
                    }
                    $this->roster[$jid] = new XMPPRosterItem($jid, $subscription, $groups);
                }
            }
            // emit this event if not emited above
            if (!$emited) {
                $this->ev->emit('on_roster_update');
            }
        }
        // if managing roster
        // catch contact vcard results
        if ($this->manage_roster && $stanza->type == 'result' && ($query = $stanza->exists('vCard', 'vcard-temp'))) {
            if (isset($this->roster[$stanza->from])) {
                $this->roster[$stanza->from]->vcard = $query;
            }
        }
        // on_get_iq, on_result_iq, and other events are only
        // emitted if on_stanza_id_{id} wasn't emitted above
        // TODO: can we add more checks here before calling back
        // e.g. checks on existence of an attribute, check on 1st level child ns and so on
        if (!$emited) {
            $this->ev->emit('on_' . $stanza->type . '_iq', array($stanza));
        }
    }