EventLayer.h

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/*******************************************************************************
 *
 * Copyright (c) 2008-2010 Michael Schulze <mschulze@ivs.cs.uni-magdeburg.de>
 * All rights reserved.
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#ifndef __EventLayer_h__
#define __EventLayer_h__

#include "debug.h"

#include "mw/common/Subject.h"
#include "mw/common/Event.h"
#include "mw/api/SubscriberEventChannel.h"
#include "mw/api/EventChannel.h"
#include "mw/nl/DistinctNL.h"
#include "mw/el/EventLayerCallBack.h"

#include "object/Queue.h"

namespace famouso {
    namespace mw {
        namespace el {

            template < class LL >
            class EventLayer : public LL {

                protected:

                    typedef LL LowerLayer;

                    // potentiell gefaerdete Datenstrukturen
                    // wegen Nebenlaeufigkeit

                    Queue Publisher;

                    Queue Subscriber;

                public:

                    typedef typename LL::SNN SNN;

                    typedef EventLayer type;

                    void init() {
                        // initialization code
                        // e.g. set callbacks and initalize all lower layers too
                        IncommingEventFromNL.bind<EventLayer<LL>, &EventLayer<LL>::fetch>(this);
                        LL::init();
                    }


                    void announce(famouso::mw::api::EventChannel<EventLayer> &ec) {
                        TRACE_FUNCTION;
                        LL::announce(ec.subject(), ec.snn());
                        Publisher.append(ec);
                    }

                    void publish(const famouso::mw::api::EventChannel<EventLayer> &ec, const Event &e) {
                        TRACE_FUNCTION;
                        ::logging::log::emit< ::logging::Info>()
                            << PROGMEMSTRING("Publish channel with addr=")
                            << ::logging::log::hex
                            << reinterpret_cast<const void*>(&ec)
                            << PROGMEMSTRING(" with Subject -> [")
                            << ec.subject().value() << ']'
                            << ::logging::log::endl;
                        // publish on all  lower layers/subnets
                        LL::publish(ec.snn(), e);

                        // publish locally on all subscribed event channels
                        publish_local(e);
                    }

                    void subscribe(famouso::mw::api::EventChannel<EventLayer> &ec) {
                        TRACE_FUNCTION;
                        ::logging::log::emit< ::logging::Info>()
                            << PROGMEMSTRING("Subscribe channel with addr=")
                            << ::logging::log::hex
                            << reinterpret_cast<const void*>(&ec)
                            << PROGMEMSTRING(" with Subject -> [")
                            << ec.subject().value() << ']'
                            << ::logging::log::endl;
                        LL::subscribe(ec.subject(), ec.snn());
                        Subscriber.append(ec);
                    }

                    void unsubscribe(famouso::mw::api::EventChannel<EventLayer> &ec) {
                        TRACE_FUNCTION;
                        Subscriber.remove(ec);
                    }

                    void unannounce(famouso::mw::api::EventChannel<EventLayer> &ec) {
                        TRACE_FUNCTION;
                        Publisher.remove(ec);
                    }

                    void publish_local(const Event &e) {
                        TRACE_FUNCTION;
                        // give start of the SubsriberList
                        typedef famouso::mw::api::SubscriberEventChannel<EventLayer> ec_t;
                        ec_t* sec = static_cast<ec_t*>(Subscriber.select());
                        // traverse the list and call the respective subscriber notify callback
                        // in case subject matching
                        while (sec) {
                            if (sec->subject() == e.subject)
                                sec->callback(e);
                            sec = static_cast<ec_t*>(sec->select());
                        }
                    }

                    void fetch(famouso::mw::nl::DistinctNL *bnl = 0) {
                        TRACE_FUNCTION;

                        // give start of the SubsriberList
                        typedef famouso::mw::api::SubscriberEventChannel<EventLayer> ec_t;
                        ec_t* sec = static_cast<ec_t*>(Subscriber.select());

                        // inform low layer about fetching starts
                        LL::event_process_request(bnl);

                        // traverse the list and try to find the correct subject,
                        // corresponding to the arised event.
                        while (sec) {
                            Event e(sec->subject());

                            // try to fetch an event from a specific subnet and SNN
                            int8_t result = LL::fetch(sec->snn(), e, bnl);

                            // incoming packet on this SNN?
                            if (result >= 0) {
                                // subject of last incoming packet matches that of the
                                // current event channel

                                // if we got a new event, publish it locally to the
                                // respective subscribers (if the packet was a fragment
                                // the corresponding event may not be complete)
                                if (result > 0)
                                    publish_local(e);

                                // packet/event processed (fetch called for each packet)
                                break;
                            }
                            sec = static_cast<ec_t*>(sec->select());
                        }
                        // inform lower layer that we are done
                        LL::event_processed();
                    }
            };

        } // namespace el
    } // namespace mw
} // namespace famouso

#endif /* __EventLayer_h__ */