/*
 * Copyright (c) 1999-2000, Eric Moon.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions, and the following disclaimer.
 *
 * 2. 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.
 *
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR "AS IS" AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF TITLE, NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT 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 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */


// ObservableHandler.h
// * PURPOSE
//   Implementation of an observable BHandler.
//
// * HISTORY
//   e.moon             19aug99         Begun.

#ifndef __ObservableHandler_H__
#define __ObservableHandler_H__

#include <Handler.h>

#include "observe.h"
#include "IObservable.h"
#include "MultiInvoker.h"

#include "cortex_defs.h"
__BEGIN_CORTEX_NAMESPACE

class ObservableHandler :
        public  BHandler,
        public  IObservable,
        private MultiInvoker {
        
        typedef BHandler _inherited;

public:                                                                                 // *** deletion
        // clients must call release() rather than deleting,
        // to ensure that all observers are notified of the
        // object's demise.  if the object has already been
        // released, return an error.

        virtual status_t release();

public:                                                                                 // *** ctor/dtor
        virtual ~ObservableHandler();
        ObservableHandler(
                const char*                                                     name=0);
        ObservableHandler(
                BMessage*                                                               archive);
                
public:                                                                                 // *** accessors
        // return true if release() has been called, false otherwise.
        bool isReleased() const;

protected:                                                                      // *** hooks
        // sends M_OBSERVER_ADDED to the newly-added observer
        virtual void observerAdded(
                const BMessenger&                               observer);

        // sends M_OBSERVER_REMOVED to the newly-removed observer               
        virtual void observerRemoved(
                const BMessenger&                               observer);

protected:                                                                      // *** internal operations
        // call to send the given message to all observers.
        // Responsibility for deletion of the message remains with
        // the caller.
        // * LOCKING: the BLooper must be locked.
        virtual status_t notify(
                BMessage*                                                               message);

        // sends M_RELEASE_OBSERVABLE
        virtual void notifyRelease();

public:                                                                                 // *** BHandler
        virtual void MessageReceived(
                BMessage*                                                               message);

public:                                                                                 // *** BArchivable
        // * LOCKING: the BLooper must be locked.
        virtual status_t Archive(
                BMessage*                                                               archive,
                bool                                                                            deep=true) const;
                
private:                                                                                // implementation
        void _handleAddObserver(
                BMessage*                                                               message); //nyi
                
        void _handleRemoveObserver(
                BMessage*                                                               message); //nyi

private:                                                                                // members
        bool                                                                                    m_released;
};

__END_CORTEX_NAMESPACE
#endif /*__ObservableHandler_H__*/