User Manual, Developers Guide and API Documentation

Delayed.hpp

Go to the documentation of this file.

/*******************************************************************************
 * This file is part of openWNS (open Wireless Network Simulator)
 * _____________________________________________________________________________
 *
 * Copyright (C) 2004-2007
 * Chair of Communication Networks (ComNets)
 * Kopernikusstr. 5, D-52074 Aachen, Germany
 * phone: ++49-241-80-27910,
 * fax: ++49-241-80-22242
 * email: info@openwns.org
 * www: http://www.openwns.org
 * _____________________________________________________________________________
 *
 * openWNS is free software; you can redistribute it and/or modify it under the
 * terms of the GNU Lesser General Public License version 2 as published by the
 * Free Software Foundation;
 *
 * openWNS is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
 * A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more
 * details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 ******************************************************************************/

#ifndef WNS_LDK_DELAYED_HPP
#define WNS_LDK_DELAYED_HPP

#include <WNS/ldk/FunctionalUnit.hpp>
#include <WNS/ldk/Receptor.hpp>

namespace wns { namespace ldk {

    struct DelayedInterface :
        public virtual FunctionalUnit
    {
        virtual void processIncoming(const CompoundPtr& compound) = 0;

        virtual void processOutgoing(const CompoundPtr&) = 0;

        virtual bool hasCapacity() const = 0;

        virtual const CompoundPtr hasSomethingToSend() const = 0;

        virtual CompoundPtr getSomethingToSend() = 0;
    };


    template <typename USER>
    class Delayed :
        public virtual FunctionalUnit,
        public virtual DelayedInterface
    {
    public:
        Delayed()
                : inWakeup(false)
            {}


        virtual void
        doSendData(const CompoundPtr& compound)
        {
            processOutgoing(compound);

            tryToSend();
        } // doSendData


        virtual void
        doOnData(const CompoundPtr& compound)
        {
            processIncoming(compound);

            tryToSend();
        } // doOnData

    protected:
        void
        tryToSend()
        {
            // first, we try to send as many compounds from our internal memory as possible. if there
            // is no PDU left to send, we wake up all our upper layers.
            // waking up upper layers may result in doSendData calls to this layer, which ends up
            // in another call to this method. if functionalUnit capacities are high, recursion depth
            // may become an issue.
            while(tryToSendOnce());

            if(!inWakeup && hasCapacity()) {
                inWakeup = true;
                getReceptor()->wakeup();
                inWakeup = false;
            }
        } // tryToSend

        virtual bool
        doIsAccepting(const CompoundPtr& /* compound */) const
        {
            return hasCapacity();
        } // isAccepting


    private:
        //
        // CompoundHandlerInterface implementation
        //

        virtual void
        doWakeup()
        {
            tryToSend();
        } // wakeup

        bool
        tryToSendOnce()
        {
            const CompoundPtr compound = hasSomethingToSend();
            if(compound == CompoundPtr())
                return false;

            if(!getConnector()->hasAcceptor(compound))
                return false;

            IConnectorReceptacle* target = getConnector()->getAcceptor(compound);
            target->sendData(getSomethingToSend());

            return true;
        } // tryToSendOnce

        bool inWakeup;
    };
}}


#endif // NOT defined WNS_LDK_DELAYED_HPP

---