summaryrefslogtreecommitdiffstats
path: root/juk/playlistinterface.h
blob: deaa900ff6fc5021012a0007bf2875acf0dd866d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
/***************************************************************************
    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:
    TQValueList<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 TQString 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