helloobject.cpp

HelloObject example application.

"Hello World" for GizmoDistribution objects.

The source code can also be found in the examples directory of the GizmoDistribution installation.

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//*****************************************************************************
// File         : helloobject.cpp
// Module       : helloobject
// Description  : helloobject (example application)
// Author       : Anders Sandblad       
// Product      : GizmoDistribution
//      
// Copyright © 2004- Saab Training Systems AB, Sweden
//          
// NOTE:    GizmoDistribution is a toolkit used for implementing distributed 
//          objects and events in C++
//
//
// Revision History...                          
//                                  
// Who  Date    Description                     
//                                  
// XAA  040416  Created file    
//
//*****************************************************************************

// Includes
#include "gzBaseLibrary.h"
#include "gzDistLibrary.h"


// Common constants
static const gzString HELLO_SESSION = "hello";
static const gzString HELLO_OBJECT = "hello";
static const gzString HELLO_ATTRIBUTE = "hello";


//-----------------------------------------------------------------------------

// A client that publish objects
class ObjectPublisher : public gzDistClientInterface
{
    public:

        ObjectPublisher();

        virtual ~ObjectPublisher();


    private:

        // callbacks

        gzVoid onClientTick();

        gzVoid onNewObject(gzDistObject* object, gzDistSession* session);

        gzVoid onRemoveObject(gzDistObject* object, gzDistSession* session);

        gzVoid onSystemShutdown();


    private:

        // members

        gzDistSessionPtr m_session;

        gzDistObjectPtr m_object;

        gzULong m_counter;

};


ObjectPublisher::ObjectPublisher() : gzDistClientInterface("publisher"), m_counter(0)
{
    // initialize client
    initialize(1);

    // get the session (create it if it does not exist)
    m_session = getSession(HELLO_SESSION, TRUE);

    // join the session
    joinSession(m_session);

    // subscribe for objects
    subscribeObjects(gzDistObject::getClassType(), m_session);

    // create an object
    gzDistObjectPtr object = new gzDistObject(HELLO_OBJECT);
    object->setAttributeValue(HELLO_ATTRIBUTE, gzString("Hello"));
    
    // add the object
    // this object instance is not necessarily identical to
    // the object actuallty added to the session
    // the added instance is captured in the onNewObject() callback
    addObject(object, m_session);

}


ObjectPublisher::~ObjectPublisher()
{
    // remove the object
    removeObject(m_object);

    // unsubscribe objects
    unsubscribeObjects(gzDistObject::getClassType(), m_session);

    // resign the session
    resignSession(m_session);

    // uninitialize client
    uninitialize();
}


gzVoid ObjectPublisher::onNewObject(gzDistObject* object, gzDistSession* session)
{
    if (!m_object)
    {
        m_object = object;
    }
}


gzVoid ObjectPublisher::onRemoveObject(gzDistObject* object, gzDistSession* session)
{
    if (object == m_object)
    {
        m_object = NULL;
    }
}


gzVoid ObjectPublisher::onClientTick()
{
    if (m_object)
    {
        updateObject(HELLO_ATTRIBUTE, gzString("Hello ")+gzString(m_counter), m_object);
        ++m_counter;
    }
}


gzVoid ObjectPublisher::onSystemShutdown()
{
    // in case of pre-mature shutdown
    m_object = NULL;
    m_session = NULL;   
}


//-----------------------------------------------------------------------------

// A client that subscribe for objects and attributes
class ObjectSubscriber : public gzDistClientInterface
{
    public:

        ObjectSubscriber();

        virtual ~ObjectSubscriber();


    private:

        // callbacks

        gzVoid onNewObject(gzDistObject* object, gzDistSession* session);
        
        gzVoid onRemoveObject(gzDistObject* object, gzDistSession* session);

        gzVoid onUpdateAttributes(const gzDistNotificationSet& attributes, gzDistObject* object, gzDistSession* session);

        gzVoid onSystemShutdown();


    private:

        // members

        gzDistSessionPtr m_session;

};


ObjectSubscriber::ObjectSubscriber() : gzDistClientInterface("subscriber")
{
    // initialize client
    initialize();

    // get the session (create it if it does not exist)
    m_session = getSession(HELLO_SESSION, TRUE);

    // join the session
    joinSession(m_session);

    // subscribe for objects
    subscribeObjects(gzDistObject::getClassType(), m_session);
}


ObjectSubscriber::~ObjectSubscriber()
{
    // Unsubscribe objects. Not really needed when the uninitialize() does it for us.
    unsubscribeObjects(gzDistObject::getClassType(), m_session);

    // Resign the session. Not really needed when the uninitialize() does it for us.
    resignSession(m_session);

    // Uninitialize client
    uninitialize();
}


gzVoid ObjectSubscriber::onNewObject(gzDistObject* object, gzDistSession* session)
{
    GZMESSAGE(GZ_MESSAGE_NOTICE, "New object: %s", (const char*)object->getName());
    subscribeAttributeValue(HELLO_ATTRIBUTE, object);
}


gzVoid ObjectSubscriber::onRemoveObject(gzDistObject* object, gzDistSession* session)
{
    GZMESSAGE(GZ_MESSAGE_NOTICE, "Removed object: %s", (const char*)object->getName());
}


gzVoid ObjectSubscriber::onUpdateAttributes(const gzDistNotificationSet& attributes, gzDistObject* object, gzDistSession* session)
{
    gzDistNotificationSetIterator iter(attributes);
    
    gzDistNotificationData* data = NULL;

    while (data = iter())
    {
        GZMESSAGE(GZ_MESSAGE_NOTICE, (const char*)data->getAttributeValue().getString());
    }
}


gzVoid ObjectSubscriber::onSystemShutdown()
{
    // in case of pre-mature shutdown
    m_session = NULL;   
}


//-----------------------------------------------------------------------------

// Application entry point
int main(int argc, char* argv[])
{
    // setup default message receiver
    gzMessage::setMessageLevel(GZ_MESSAGE_NOTICE);

    // create manager and start
    gzDistManagerPtr manager = gzDistManager::getManager(TRUE);
    manager->start();

    // create subscriber client
    ObjectSubscriber* subscriber = new ObjectSubscriber;

    gzSleep(GZ_SLEEP_SECOND);

    // create publisher client
    ObjectPublisher* publisher = new ObjectPublisher;


    // run a while
    gzSleep(10 * GZ_SLEEP_SECOND);
    

    // delete the publisher
    delete publisher;

    gzSleep(GZ_SLEEP_SECOND);

    // delete the subscriber
    delete subscriber;

    // shut down and release manager
    manager->shutDown();
    manager = NULL;

    gzSleep(GZ_SLEEP_SECOND);

    return 0;

}

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