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/***************************************************************************
copyright : (C) 2004 by Scott Wheeler
email : wheeler@kde.org
***************************************************************************/
/***************************************************************************
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
***************************************************************************/
#ifndef PLAYLISTINTERFACE_H
#define PLAYLISTINTERFACE_H
#include "filehandle.h"
class PlaylistObserver;
/**
* An interface implemented by PlaylistInterface to make it possible to watch
* for changes in the PlaylistInterface. This is a semi-standard observer
* pattern from i.e. Design Patterns.
*/
class Watched
{
public:
void addObserver(PlaylistObserver *observer);
void removeObserver(PlaylistObserver *observer);
/**
* This is triggered when the currently playing item has been changed.
*/
virtual void currentChanged();
/**
* This is triggered when the data in the playlist -- i.e. the tag content
* changes.
*/
virtual void dataChanged();
protected:
virtual ~Watched();
private:
QValueList<PlaylistObserver *> m_observers;
};
/**
* This is a simple interface that should be used by things that implement a
* playlist-like API.
*/
class PlaylistInterface : public Watched
{
public:
virtual QString name() const = 0;
virtual FileHandle currentFile() const = 0;
virtual int time() const = 0;
virtual int count() const = 0;
virtual void playNext() = 0;
virtual void playPrevious() = 0;
virtual void playNextAlbum() = 0;
virtual void stop() = 0;
virtual bool playing() const = 0;
};
class PlaylistObserver
{
public:
virtual ~PlaylistObserver();
/**
* This method must be implemented in concrete implementations; it should
* define what action should be taken in the observer when the currently
* playing item changes.
*/
virtual void updateCurrent() = 0;
/**
* This method must be implemented in concrete implementations; it should
* define what action should be taken when the data of the PlaylistItems in
* the playlist changes.
*/
virtual void updateData() = 0;
void clearWatched() { m_playlist = 0; }
protected:
PlaylistObserver(PlaylistInterface *playlist);
const PlaylistInterface *playlist() const;
private:
PlaylistInterface *m_playlist;
};
#endif
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