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21 
22 
23 
24 #ifndef INCLUDED_SLIDESHOW_VIEWUPDATE_HXX
25 #define INCLUDED_SLIDESHOW_VIEWUPDATE_HXX
26 
27 #include "disposable.hxx"
28 #include "view.hxx"
29 #include <boost/shared_ptr.hpp>
30 
31 /* Definition of ViewUpdate interface */
32 
33 namespace slideshow
34 {
35     namespace internal
36     {
37         /** Interface for something that can perform view updates.
38 
39             Use this interface for objects that perform view updates
40             from time to time, e.g. slide content. Availability of
41             updates can be queried, and subsequently performed.
42          */
43         class ViewUpdate : public Disposable
44         {
45         public:
46             /** Perform the update action on all views
47 
48                 @return true, if the update was performed
49                 successfully, false otherwise.
50              */
51             virtual bool update() = 0;
52 
53             /** Perform the update action on given view only
54 
55                 @return true, if the update was performed
56                 successfully, false otherwise.
57              */
58             virtual bool update( ViewSharedPtr const& rView ) = 0;
59 
60             /** Query whether updates are pending
61 
62                 @return true, if updates are pending. Calling update()
63                 subsequently will perform the pending update then.
64              */
65             virtual bool needsUpdate() const = 0;
66         };
67 
68         typedef ::boost::shared_ptr< ViewUpdate > ViewUpdateSharedPtr;
69     }
70 }
71 
72 #endif /* INCLUDED_SLIDESHOW_VIEWUPDATE_HXX */
73