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// -*- C++ -*-
//=============================================================================
/**
* @file Widget_Impl.h
*
* $Id: Widget_Impl.h 80826 2008-03-04 14:51:23Z wotte $
*
* @author Christopher Kohlhoff <chris@kohlhoff.com>
*/
//=============================================================================
#ifndef WIDGET_IMPL_H
#define WIDGET_IMPL_H
#include "Widget.h"
#include "Widget_Part.h"
#include "ace/Unbounded_Queue.h"
#include "ace/Refcounted_Auto_Ptr.h"
#include "ace/Synch_Traits.h"
#include "ace/Thread_Mutex.h"
/**
* @class Widget_Impl
*
* @brief An implementation of the Widget interface.
*/
class Widget_Impl : public Widget
{
public:
/// Constructor.
Widget_Impl (void);
/// Destructor.
virtual ~Widget_Impl (void);
/// Add a new part to the widget. The widget takes ownership of the part
/// object.
virtual void add_part (Widget_Part *part);
/// Remove a random part from the widget. Ownership of the part is returned
/// to the caller.
virtual Widget_Part *remove_part (void);
/// Ask the widget to print information about the parts that it contains.
virtual void list_parts (void);
private:
/// The parts which make up this widget. The set actually contains instances
/// of ACE_Refcounted_Auto_Ptr to automatically manage the lifetimes of the
/// constituent parts.
///
/// Some things to note about the choice of ACE_Refcounted_Auto_Ptr:
/// - We cannot use auto_ptr to manage the objects, since auto_ptr does not
/// support the copying and assignment semantics necessary for storage in
/// a container.
/// - The ACE_Strong_Bound_Ptr reference counted pointer could be used to
/// store objects in a container, however (for reasons of safety) it
/// provides no way to release ownership of the object from the smart
/// pointer. We need to be able to release ownership to implement the
/// remove_part method.
/// - ACE_Refcounted_Ptr can both be stored in containers and allows us to
/// release ownership of the pointer that it contains.
ACE_Unbounded_Queue<ACE_Refcounted_Auto_Ptr<Widget_Part, ACE_SYNCH_MUTEX> > parts_;
};
#endif /* WIDGET_IMPL_H */
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