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# main.cpp Example File

statemachine/pingpong/main.cpp

     /****************************************************************************
     **
     ** Copyright (C) 2012 Digia Plc and/or its subsidiary(-ies).
     ** Contact: http://www.qt-project.org/legal
     **
     ** This file is part of the QtCore module of the Qt Toolkit.
     **
     ** $QT_BEGIN_LICENSE:BSD$
     ** You may use this file under the terms of the BSD license as follows:
     **
     ** "Redistribution and use in source and binary forms, with or without
     ** modification, are permitted provided that the following conditions are
     ** met:
     **   * Redistributions of source code must retain the above copyright
     **     notice, this list of conditions and the following disclaimer.
     **   * Redistributions in binary form must reproduce the above copyright
     **     notice, this list of conditions and the following disclaimer in
     **     the documentation and/or other materials provided with the
     **     distribution.
     **   * Neither the name of Digia Plc and its Subsidiary(-ies) nor the names
     **     of its contributors may be used to endorse or promote products derived
     **     from this software without specific prior written permission.
     **
     **
     ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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     ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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     ****************************************************************************/

     #include <QtCore>
     #include <stdio.h>

     class PingEvent : public QEvent
     {
     public:
         PingEvent() : QEvent(QEvent::Type(QEvent::User+2))
             {}
     };

     class PongEvent : public QEvent
     {
     public:
         PongEvent() : QEvent(QEvent::Type(QEvent::User+3))
             {}
     };

     class Pinger : public QState
     {
     public:
         Pinger(QState *parent)
             : QState(parent) {}

     protected:
         virtual void onEntry(QEvent *)
         {
             machine()->postEvent(new PingEvent());
             fprintf(stdout, "ping?\n");
         }
     };

     class PongTransition : public QAbstractTransition
     {
     public:
         PongTransition() {}

     protected:
         virtual bool eventTest(QEvent *e) {
             return (e->type() == QEvent::User+3);
         }
         virtual void onTransition(QEvent *)
         {
             machine()->postDelayedEvent(new PingEvent(), 500);
             fprintf(stdout, "ping?\n");
         }
     };

     class PingTransition : public QAbstractTransition
     {
     public:
         PingTransition() {}

     protected:
         virtual bool eventTest(QEvent *e) {
             return (e->type() == QEvent::User+2);
         }
         virtual void onTransition(QEvent *)
         {
             machine()->postDelayedEvent(new PongEvent(), 500);
             fprintf(stdout, "pong!\n");
         }
     };

     int main(int argc, char **argv)
     {
         QCoreApplication app(argc, argv);

         QStateMachine machine;
         QState *group = new QState(QState::ParallelStates);
         group->setObjectName("group");

         Pinger *pinger = new Pinger(group);
         pinger->setObjectName("pinger");
         pinger->addTransition(new PongTransition());

         QState *ponger = new QState(group);
         ponger->setObjectName("ponger");
         ponger->addTransition(new PingTransition());

         machine.addState(group);
         machine.setInitialState(group);
         machine.start();

         return app.exec();
     }