libkcal/calendarnull.h

   1 /*
   2     This file is part of libkcal.
   3
   4     Copyright (c) 2003 Cornelius Schumacher <schumacher@kde.org>
   5
   6     This library is free software; you can redistribute it and/or
   7     modify it under the terms of the GNU Library General Public
   8     License as published by the Free Software Foundation; either
   9     version 2 of the License, or (at your option) any later version.
  10
  11     This library is distributed in the hope that it will be useful,
  12     but WITHOUT ANY WARRANTY; without even the implied warranty of
  13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14     Library General Public License for more details.
  15
  16     You should have received a copy of the GNU Library General Public License
  17     along with this library; see the file COPYING.LIB.  If not, write to
  18     the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  19     Boston, MA 02111-1307, USA.
  20 */
  21 #ifndef KCAL_CALENDARNULL_H
  22 #define KCAL_CALENDARNULL_H
  23
  24 #include "calendar.h"
  25
  26 class KConfig;
  27
  28 namespace KCal {
  29
  30 /**
  31   This is a null calendar object which does nothing. It can be passed to
  32   functions which need a calendar object when there actually isn't a real
  33   calendar yet. CalendarNull can be used to implement the null object design
  34   pattern. Instead of passing a 0 pointer and checking for 0 with each access
  35   a CalendarNull object can be passed.
  36 */
  37 class CalendarNull : public Calendar
  38 {
  39   public:
  40     CalendarNull() {}
  41     ~CalendarNull() {}
  42
  43     static CalendarNull *self();
  44
  45     void incidenceUpdated( IncidenceBase * ) {}
  46
  47     void close() {}
  48     void save() {}
  49
  50     bool addEvent( Event * ) { return false; }
  51     void deleteEvent( Event * ) {}
  52     Event *event( const QString & ) { return 0; }
  53     Event::List rawEvents( EventSortField, SortDirection ) { return Event::List(); }
  54     Event::List rawEvents( const QDate &, const QDate &, bool ) { return Event::List(); }
  55     Event::List rawEventsForDate( const QDateTime & ) { return Event::List(); }
  56     Event::List rawEventsForDate( const QDate &, bool ) { return Event::List(); }
  57
  58     bool addTodo( Todo * ) { return false; }
  59     void deleteTodo( Todo * ) {}
  60     Todo *todo( const QString & ) { return 0; }
  61     Todo::List rawTodos( TodoSortField, SortDirection ) { return Todo::List(); }
  62     Todo::List rawTodosForDate( const QDate & ) { return Todo::List(); }
  63
  64     bool addJournal( Journal * ) { return false; }
  65     void deleteJournal( Journal * ) {}
  66     Journal *journal( const QString & ) { return 0; }
  67     Journal::List rawJournals( JournalSortField, SortDirection ) { return Journal::List(); }
  68     Journal::List rawJournalsForDate( const QDate & ) { return Journal::List(); }
  69
  70     Alarm::List alarms( const QDateTime &, const QDateTime & ) { return Alarm::List(); }
  71
  72   private:
  73     static CalendarNull *mSelf;
  74
  75     class Private;
  76     Private *d;
  77 };
  78
  79 }
  80
  81 #endif