Copy the KDE 3.5 branch to branches/trinity for new KDE 3.5 features.

BUG:215923


git-svn-id: svn://anonsvn.kde.org/home/kde/branches/trinity/kdepim@1054174 283d02a7-25f6-0310-bc7c-ecb5cbfe19da

1 files changed, 958 insertions, 0 deletions

diff --git a/libkcal/calendar.h b/libkcal/calendar.h
new file mode 100644
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+++ b/libkcal/calendar.h
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+/*
+    This file is part of libkcal.
+
+    Copyright (c) 1998 Preston Brown <pbrown@kde.org>
+    Copyright (c) 2001,2003,2004 Cornelius Schumacher <schumacher@kde.org>
+    Copyright (C) 2003-2004 Reinhold Kainhofer <reinhold@kainhofer.com>
+
+    This library is free software; you can redistribute it and/or
+    modify it under the terms of the GNU Library General Public
+    License as published by the Free Software Foundation; either
+    version 2 of the License, or (at your option) any later version.
+
+    This library is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+    Library General Public License for more details.
+
+    You should have received a copy of the GNU Library General Public License
+    along with this library; see the file COPYING.LIB.  If not, write to
+    the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+    Boston, MA 02110-1301, USA.
+*/
+/**
+   @file calendar.h
+   Provides the main "calendar" object class.
+
+   @author Preston Brown
+   @author Cornelius Schumacher
+   @author Reinhold Kainhofer
+ */
+#ifndef KCAL_CALENDAR_H
+#define KCAL_CALENDAR_H
+
+#include <qobject.h>
+#include <qstring.h>
+#include <qdatetime.h>
+#include <qptrlist.h>
+#include <qdict.h>
+#include <kdepimmacros.h>
+
+#include "customproperties.h"
+#include "event.h"
+#include "todo.h"
+#include "journal.h"
+#include "kcalversion.h"
+#include "person.h"
+
+/**
+   @namespace KCal
+   Namespace KCal is for global classes, objects and/or functions in libkcal.
+*/
+namespace KCal {
+
+class CalFilter;
+
+/**
+   @enum SortDirection
+   Sort direction.
+*/
+enum SortDirection
+{
+  /** Sort in ascending order (first to last) */
+  SortDirectionAscending,
+  /** Sort in descending order (last to first) */
+  SortDirectionDescending
+};
+
+/**
+   @enum EventSortField
+   How Events are to be sorted.
+*/
+enum EventSortField
+{
+  /** Events are to be unsorted */
+  EventSortUnsorted,
+  /** Sort Events chronologically, by start date */
+  EventSortStartDate,
+  /** Sort Events chronologically, by end date */
+  EventSortEndDate,
+  /** Sort Events alphabetically, by summary */
+  EventSortSummary
+};
+
+/**
+   @enum TodoSortField
+   How Todos are to be sorted.
+*/
+enum TodoSortField
+{
+  /** Todos are to be unsorted */
+  TodoSortUnsorted,
+  /** Sort Todos chronologically, by start date */
+  TodoSortStartDate,
+  /** Sort Todos chronologically, by due date */
+  TodoSortDueDate,
+  /** Sort Todos by priority */
+  TodoSortPriority,
+  /** Sort Todos by percentage completed */
+  TodoSortPercentComplete,
+  /** Sort Todos alphabetically, by summary */
+  TodoSortSummary
+};
+
+/**
+   @enum JournalSortField
+   How Journals are to be sorted.
+*/
+enum JournalSortField
+{
+  /** Journals are to be unsorted */
+  JournalSortUnsorted,
+  /** Sort Journals chronologically by date */
+  JournalSortDate,
+  /** Sort Journals alphabetically, by summary */
+  JournalSortSummary
+};
+
+/**
+   @class Calendar
+
+   This is the main "calendar" object class.  It holds information like
+   Incidences(Events, To-dos, Journals), user information, etc. etc.
+
+   This is an abstract base class defining the interface to a calendar. It is
+   implemented by subclasses like CalendarLocal, which use different
+   methods to store and access the data.
+
+   <b>Ownership of Incidences</b>:
+
+   Incidence ownership is handled by the following policy: As soon as an
+   Incidence (or any other subclass of IncidenceBase) object is added to the
+   Calendar by an add...() method it is owned by the Calendar object.
+   The Calendar takes care of deleting it.  All Incidences returned by the
+   query functions are returned as pointers so that changes to the returned
+   Incidences are immediately visible in the Calendar.  Do <em>Not</em>
+   delete any Incidence object you get from Calendar.
+
+   <b>Time Zone Handling</b>:
+
+   - Incidence Storing:
+      - By default, (when LocalTime is unset) Incidence dates will have the
+        "UTC" time zone when stored into a calendar file.
+      - To store Incidence dates without a time zone (i.e, "floating time
+        zone") LocalTime must be set using the setLocalTime() method.
+
+   - Incidence Viewing:
+      - By default, Incidence dates will have the "UTC" time zone when
+        read from a calendar.
+      - To view Incidence dates using another time zone TimeZoneId must
+        be set using the setTimeZoneId() method, or the TimeZoneId can
+        be passed to the Calendar constructor.
+      - It is permitted to switch viewing time zones using setTimeZoneId()
+        as desired after the Calendar object has been constructed.
+
+   - Note that:
+      - The Calendar class doesn't do anything with TimeZoneId: it simply
+        saves it for later use by the ICalFormat class.
+      - The ICalFormat class takes TimeZoneId and applies it to loaded
+        Incidences before returning them in ICalFormat::load().
+      - Each Incidence can have its own time zone (or have a floating
+        time zone).
+      - Once an Incidence is loaded it is adjusted to use the viewing
+        time zone, TimeZoneId.
+      - Depending on the LocalTime setting, all loaded Incidences are stored
+        either in UTC or without a time zone (floating time zone).
+*/
+class LIBKCAL_EXPORT Calendar : public QObject, public CustomProperties,
+                                public IncidenceBase::Observer
+{
+    Q_OBJECT
+
+  public:
+
+    /**
+       Construct Calendar object using a Time Zone.
+
+       @param timeZoneId is a string containing a Time Zone ID, which is
+       assumed to be valid. The Time Zone Id is used to set the time zone
+       for viewing Incidence dates.\n
+       On some systems, /usr/share/zoneinfo/zone.tab may be available for
+       reference.\n
+       @e Example: "Europe/Berlin"
+
+       @warning
+       Do Not pass an empty timeZoneId string as this may cause unintended
+       consequences when storing Incidences into the Calendar.
+    */
+    Calendar( const QString &timeZoneId );
+
+    /**
+       Destructor
+    */
+    virtual ~Calendar();
+
+    /**
+       Set the Calendar Product ID.
+
+       @param productId is a QString containing the Product ID.
+    */
+    void setProductId( const QString &productId );
+
+    /**
+       Get the Calendar's Product ID.
+
+       @return the string containing the Product ID
+    */
+    QString productId();
+
+    /**
+       Set the owner of the Calendar.
+
+       @param owner is a Person object.
+    */
+    void setOwner( const Person &owner );
+
+    /**
+       Get the owner of the Calendar.
+
+       @return the owner Person object.
+    */
+    const Person &getOwner() const;
+
+    /**
+       Set the Time Zone Id for the Calendar.
+
+       @param timeZoneId is a string containing a Time Zone ID, which is
+       assumed to be valid. The Time Zone Id is used to set the time zone
+       for viewing Incidence dates.\n
+       On some systems, /usr/share/zoneinfo/zone.tab may be available for
+       reference.\n
+       @e Example: "Europe/Berlin"
+
+       @warning
+       Do Not pass an empty timeZoneId string as this may cause unintended
+       consequences when storing Incidences into the Calendar.
+    */
+    void setTimeZoneId( const QString &timeZoneId );
+
+    /**
+     * Set the timezone used for viewing the incidences in this calendar. In
+     * case it differs from the current timezone, shift the events such that they
+     * retain their absolute time (in UTC).
+     * @ref setTimeZoneId
+     */
+    virtual void setTimeZoneIdViewOnly( const QString &timeZoneId ) = 0;
+
+    /**
+       Get the Time Zone ID for the Calendar.
+
+       @return the string containg the Time Zone ID.
+    */
+    QString timeZoneId() const;
+
+    /**
+       Set to store calendar Incidences without a time zone.
+    */
+    void setLocalTime();
+
+    /**
+       Determine if Calendar Incidences are to be written without a time zone.
+
+       @return true if the Calendar is set to write Incidences withoout
+       a time zone; false otherwise.
+    */
+    bool isLocalTime() const;
+
+    /**
+       Set if the Calendar had been modified.
+
+       @param modified is true if the Calendar has been modified since open
+       or last save.
+    */
+    void setModified( bool modified );
+
+    /**
+       Determine the Calendar's modification status.
+
+       @return true if the Calendar has been modified since open or last save.
+    */
+    bool isModified() const { return mModified; }
+
+    /**
+       Clears out the current Calendar, freeing all used memory etc.
+    */
+    virtual void close() = 0;
+
+    /**
+       Sync changes in memory to persistant storage.
+    */
+    virtual void save() = 0;
+
+    /**
+     * Load the calendar contents from storage. This requires the calendar to have been loaded
+     * once before, in other words initialized.
+     * @par tz The timezone to use for loading.
+     */
+    virtual bool reload( const QString &tz ) = 0;
+
+    /**
+       Determine if the Calendar is currently being saved.
+
+       @return true if the Calendar is currently being saved; false otherwise.
+    */
+    virtual bool isSaving() { return false; }
+
+    /**
+       Return a list of all categories used by Incidences in this Calendar.
+
+       @return a QStringList containing all the categories.
+    */
+    QStringList categories();
+
+// Incidence Specific Methods //
+
+    /**
+       Insert an Incidence into the Calendar.
+
+       @param incidence is a pointer to the Incidence to insert.
+
+       @return true if the Incidence was successfully inserted; false otherwise.
+    */
+    virtual bool addIncidence( Incidence *incidence );
+
+    /**
+       Remove an Incidence from the Calendar.
+
+       @param incidence is a pointer to the Incidence to remove.
+
+       @return true if the Incidence was successfully removed; false otherwise.
+    */
+    virtual bool deleteIncidence( Incidence *incidence );
+
+    /**
+       Return a filtered list of all Incidences for this Calendar.
+
+       @return the list of all filtered Incidences.
+    */
+    virtual Incidence::List incidences();
+
+    /**
+       Return a filtered list of all Incidences which occur on the given date.
+
+       @param date request filtered Incidence list for this QDate only.
+
+       @return the list of filtered Incidences occurring on the specified date.
+    */
+    virtual Incidence::List incidences( const QDate &date );
+
+    /**
+       Return an unfiltered list of all Incidences for this Calendar.
+
+       @return the list of all unfiltered Incidences.
+    */
+    virtual Incidence::List rawIncidences();
+
+    /**
+       Returns the Incidence associated with the given unique identifier.
+
+       @param uid is a unique identifier string.
+
+       @return a pointer to the Incidence.
+       A null pointer is returned if no such Incidence exists.
+    */
+    Incidence *incidence( const QString &uid );
+
+    /**
+       Returns the Incidence associated with the given scheduling identifier.
+
+       @param sid is a unique scheduling identifier string.
+
+       @return a pointer to the Incidence.
+       A null pointer is returned if no such Incidence exists.
+    */
+    Incidence *incidenceFromSchedulingID( const QString &sid );
+
+    /**
+     * Searches all events and todos for (an incidence with this
+     * scheduling ID. Returns a list of matching results.
+     **/
+    Incidence::List incidencesFromSchedulingID( const QString &UID );
+
+    /**
+       Create a merged list of Events, Todos, and Journals.
+
+       @param events is an Event list to merge.
+       @param todos is a Todo list to merge.
+       @param journals is a Journal list to merge.
+
+       @return a list of merged Incidences.
+    */
+    static Incidence::List mergeIncidenceList( const Event::List &events,
+                                               const Todo::List &todos,
+                                               const Journal::List &journals );
+
+    /**
+       Flag that a change to a Calendar Incidence is starting.
+
+       @param incidence is a pointer to the Incidence that will be changing.
+    */
+    virtual bool beginChange( Incidence *incidence );
+
+    /**
+       Flag that a change to a Calendar Incidence has completed.
+
+       @param incidence is a pointer to the Incidence that was changed.
+    */
+    virtual bool endChange( Incidence *incidence );
+
+    /**
+       Dissociate an Incidence from a recurring Incidence.
+       By default, only one single Incidence for the specified @a date
+       will be dissociated and returned.  If @a single is false, then
+       the recurrence will be split at @a date, the old Incidence will
+       have its recurrence ending at @a date and the new Incidence
+       will have all recurrences past the @a date.
+
+       @param incidence is a pointer to a recurring Incidence.
+       @param date is the QDate within the recurring Incidence on which
+       the dissociation will be performed.
+       @param single is a flag meaning that a new Incidence should be created
+       from the recurring Incidences after @a date.
+
+       @return a pointer to a new recurring Incidence if @a single is false.
+    */
+    Incidence *dissociateOccurrence( Incidence *incidence, QDate date,
+                                     bool single = true );
+
+// Event Specific Methods //
+
+    /**
+       Insert an Event into the Calendar.
+
+       @param event is a pointer to the Event to insert.
+
+       @return true if the Event was successfully inserted; false otherwise.
+    */
+    virtual bool addEvent( Event *event ) = 0;
+
+    /**
+       Remove an Event from the Calendar.
+
+       @param event is a pointer to the Event to remove.
+
+       @return true if the Event was successfully remove; false otherwise.
+    */
+    virtual bool deleteEvent( Event *event ) = 0;
+
+    /**
+       Sort a list of Events.
+
+       @param eventList is a pointer to a list of Events.
+       @param sortField specifies the EventSortField.
+       @param sortDirection specifies the SortDirection.
+
+       @return a list of Events sorted as specified.
+    */
+    static Event::List sortEvents( Event::List *eventList,
+                                   EventSortField sortField,
+                                   SortDirection sortDirection );
+    /**
+       Return a sorted, filtered list of all Events for this Calendar.
+
+       @param sortField specifies the EventSortField.
+       @param sortDirection specifies the SortDirection.
+
+       @return the list of all filtered Events sorted as specified.
+    */
+    virtual Event::List events(
+      EventSortField sortField = EventSortUnsorted,
+      SortDirection sortDirection = SortDirectionAscending );
+
+    /**
+       Return a filtered list of all Events which occur on the given timestamp.
+
+       @param qdt request filtered Event list for this QDateTime only.
+
+       @return the list of filtered Events occurring on the specified timestamp.
+    */
+    Event::List events( const QDateTime &qdt );
+
+    /**
+       Return a filtered list of all Events occurring within a date range.
+
+       @param start is the starting date.
+       @param end is the ending date.
+       @param inclusive if true only Events which are completely included
+       within the date range are returned.
+
+       @return the list of filtered Events occurring within the specified
+       date range.
+    */
+    Event::List events( const QDate &start, const QDate &end,
+                        bool inclusive = false);
+
+    /**
+       Return a sorted, filtered list of all Events which occur on the given
+       date.  The Events are sorted according to @a sortField and
+       @a sortDirection.
+
+       @param date request filtered Event list for this QDate only.
+       @param sortField specifies the EventSortField.
+       @param sortDirection specifies the SortDirection.
+
+       @return the list of sorted, filtered Events occurring on @a date.
+    */
+    Event::List events(
+      const QDate &date,
+      EventSortField sortField = EventSortUnsorted,
+      SortDirection sortDirection = SortDirectionAscending );
+
+    /**
+       Return a sorted, unfiltered list of all Events for this Calendar.
+
+       @param sortField specifies the EventSortField.
+       @param sortDirection specifies the SortDirection.
+
+       @return the list of all unfiltered Events sorted as specified.
+    */
+    virtual Event::List rawEvents(
+      EventSortField sortField = EventSortUnsorted,
+      SortDirection sortDirection = SortDirectionAscending ) = 0;
+
+    /**
+       Return an unfiltered list of all Events which occur on the given
+       timestamp.
+
+       @param qdt request unfiltered Event list for this QDateTime only.
+
+       @return the list of unfiltered Events occurring on the specified
+       timestamp.
+    */
+    virtual Event::List rawEventsForDate( const QDateTime &qdt ) = 0;
+
+    /**
+       Return an unfiltered list of all Events occurring within a date range.
+
+       @param start is the starting date.
+       @param end is the ending date.
+       @param inclusive if true only Events which are completely included
+       within the date range are returned.
+
+       @return the list of unfiltered Events occurring within the specified
+       date range.
+    */
+    virtual Event::List rawEvents( const QDate &start, const QDate &end,
+                                   bool inclusive = false ) = 0;
+
+    /**
+       Return a sorted, unfiltered list of all Events which occur on the given
+       date.  The Events are sorted according to @a sortField and
+       @a sortDirection.
+
+       @param date request unfiltered Event list for this QDate only.
+       @param sortField specifies the EventSortField.
+       @param sortDirection specifies the SortDirection.
+
+       @return the list of sorted, unfiltered Events occurring on @a date.
+    */
+    virtual Event::List rawEventsForDate(
+      const QDate &date,
+      EventSortField sortField = EventSortUnsorted,
+      SortDirection sortDirection = SortDirectionAscending ) = 0;
+
+    /**
+       Returns the Event associated with the given unique identifier.
+
+       @param uid is a unique identifier string.
+
+       @return a pointer to the Event.
+       A null pointer is returned if no such Event exists.
+    */
+    virtual Event *event( const QString &uid ) = 0;
+
+// Todo Specific Methods //
+
+    /**
+       Insert a Todo into the Calendar.
+
+       @param todo is a pointer to the Todo to insert.
+
+       @return true if the Todo was successfully inserted; false otherwise.
+    */
+    virtual bool addTodo( Todo *todo ) = 0;
+
+    /**
+       Remove a Todo from the Calendar.
+
+       @param todo is a pointer to the Todo to remove.
+
+       @return true if the Todo was successfully removed; false otherwise.
+    */
+    virtual bool deleteTodo( Todo *todo ) = 0;
+
+    /**
+       Sort a list of Todos.
+
+       @param todoList is a pointer to a list of Todos.
+       @param sortField specifies the TodoSortField.
+       @param sortDirection specifies the SortDirection.
+
+       @return a list of Todos sorted as specified.
+    */
+    static Todo::List sortTodos( Todo::List *todoList,
+                                 TodoSortField sortField,
+                                 SortDirection sortDirection );
+
+    /**
+       Return a sorted, filtered list of all Todos for this Calendar.
+
+       @param sortField specifies the TodoSortField.
+       @param sortDirection specifies the SortDirection.
+
+       @return the list of all filtered Todos sorted as specified.
+    */
+    virtual Todo::List todos(
+      TodoSortField sortField = TodoSortUnsorted,
+      SortDirection sortDirection = SortDirectionAscending );
+
+    /**
+       Return a filtered list of all Todos which are due on the specified date.
+
+       @param date request filtered Todos due on this QDate.
+
+       @return the list of filtered Todos due on the specified date.
+    */
+    virtual Todo::List todos( const QDate &date );
+
+    /**
+       Return a sorted, unfiltered list of all Todos for this Calendar.
+
+       @param sortField specifies the TodoSortField.
+       @param sortDirection specifies the SortDirection.
+
+       @return the list of all unfiltered Todos sorted as specified.
+    */
+    virtual Todo::List rawTodos(
+      TodoSortField sortField = TodoSortUnsorted,
+      SortDirection sortDirection = SortDirectionAscending ) = 0;
+
+    /**
+       Return an unfiltered list of all Todos which due on the specified date.
+
+       @param date request unfiltered Todos due on this QDate.
+
+       @return the list of unfiltered Todos due on the specified date.
+    */
+    virtual Todo::List rawTodosForDate( const QDate &date ) = 0;
+
+    /**
+       Returns the Todo associated with the given unique identifier.
+
+       @param uid is a unique identifier string.
+
+       @return a pointer to the Todo.
+       A null pointer is returned if no such Todo exists.
+    */
+    virtual Todo *todo( const QString &uid ) = 0;
+
+// Journal Specific Methods //
+
+    /**
+       Insert a Journal into the Calendar.
+
+       @param journal is a pointer to the Journal to insert.
+
+       @return true if the Journal was successfully inserted; false otherwise.
+    */
+    virtual bool addJournal( Journal *journal ) = 0;
+
+    /**
+       Remove a Journal from the Calendar.
+
+       @param journal is a pointer to the Journal to remove.
+
+       @return true if the Journal was successfully removed; false otherwise.
+    */
+    virtual bool deleteJournal( Journal *journal ) = 0;
+
+    /**
+       Sort a list of Journals.
+
+       @param journalList is a pointer to a list of Journals.
+       @param sortField specifies the JournalSortField.
+       @param sortDirection specifies the SortDirection.
+
+       @return a list of Journals sorted as specified.
+    */
+    static Journal::List sortJournals( Journal::List *journalList,
+                                       JournalSortField sortField,
+                                       SortDirection sortDirection );
+    /**
+       Return a sorted, filtered list of all Journals for this Calendar.
+
+       @param sortField specifies the JournalSortField.
+       @param sortDirection specifies the SortDirection.
+
+       @return the list of all filtered Journals sorted as specified.
+    */
+    virtual Journal::List journals(
+      JournalSortField sortField = JournalSortUnsorted,
+      SortDirection sortDirection = SortDirectionAscending );
+
+    /**
+       Return a filtered list of all Journals for on the specifed date.
+
+       @param date request filtered Journals for this QDate only.
+
+       @return the list of filtered Journals for the specified date.
+    */
+    virtual Journal::List journals( const QDate &date );
+
+    /**
+       Return a sorted, unfiltered list of all Journals for this Calendar.
+
+       @param sortField specifies the JournalSortField.
+       @param sortDirection specifies the SortDirection.
+
+       @return the list of all unfiltered Journals sorted as specified.
+    */
+    virtual Journal::List rawJournals(
+      JournalSortField sortField = JournalSortUnsorted,
+      SortDirection sortDirection = SortDirectionAscending ) = 0;
+
+    /**
+       Return an unfiltered list of all Journals for on the specifed date.
+
+       @param date request unfiltered Journals for this QDate only.
+
+       @return the list of unfiltered Journals for the specified date.
+    */
+    virtual Journal::List rawJournalsForDate( const QDate &date ) = 0;
+
+    /**
+       Returns the Journal associated with the given unique identifier.
+
+       @param uid is a unique identifier string.
+
+       @return a pointer to the Journal.
+       A null pointer is returned if no such Journal exists.
+    */
+    virtual Journal *journal( const QString &uid ) = 0;
+
+// Relations Specific Methods //
+
+    /**
+       Setup Relations for an Incidence.
+
+       @param incidence is a pointer to the Incidence to have a
+       Relation setup.
+    */
+    virtual void setupRelations( Incidence *incidence );
+
+    /**
+       Remove all Relations from an Incidence.
+
+       @param incidence is a pointer to the Incidence to have a
+       Relation removed.
+    */
+    virtual void removeRelations( Incidence *incidence );
+
+// Filter Specific Methods //
+
+    /**
+       Set the Calendar filter.
+
+       @param filter a pointer to a CalFilter object which will be
+       used to filter Calendar Incidences.
+    */
+    void setFilter( CalFilter *filter );
+
+    /**
+       Return the Calendar filter.
+
+       @return a pointer to the Calendar CalFilter.
+       A null pointer is returned if no such CalFilter exists.
+    */
+    CalFilter *filter();
+
+// Alarm Specific Methods //
+
+    /**
+       Return a list of Alarms within a time range for this Calendar.
+
+       @param from is the starting timestamp.
+       @param to is the ending timestamp.
+
+       @return the list of Alarms for the for the specified time range.
+    */
+    virtual Alarm::List alarms( const QDateTime &from,
+                                const QDateTime &to ) = 0;
+
+// Observer Specific Methods //
+
+    /**
+       @class Observer
+
+       The Observer class.
+    */
+    class Observer
+    {
+      public:
+        virtual ~Observer() {}
+        /**
+           Notify the Observer that a Calendar has been modified.
+
+           First parameter is true if the Calendar has been modified.\n
+           Second parameter is a pointer to the Calendar object that
+           is being observed.
+        */
+        virtual void calendarModified( bool /*modified*/,
+                                       Calendar * /*calendar*/ ) {};
+
+        /**
+           Notify the Observer that an Incidence has been inserted.
+
+           First parameter is a pointer to the Incidence that was inserted.
+        */
+        virtual void calendarIncidenceAdded( Incidence * /*incidence*/ ) {}
+
+        /**
+           Notify the Observer that an Incidence has been modified.
+
+           First parameter is a pointer to the Incidence that was modified.
+        */
+        virtual void calendarIncidenceChanged( Incidence * /*incidence*/ ) {}
+
+        /**
+           Notify the Observer that an Incidence has been removed.
+
+           First parameter is a pointer to the Incidence that was removed.
+        */
+          virtual void calendarIncidenceDeleted( Incidence * /*incidence*/ ) {}
+    };
+
+    /**
+       Register an Observer for this Calendar.
+
+       @param observer is a pointer to an Observer object that will be
+       watching this Calendar.
+     */
+    void registerObserver( Observer *observer );
+
+    /**
+       Unregister an Observer for this Calendar.
+
+       @param observer is a pointer to an Observer object that has been
+       watching this Calendar.
+     */
+    void unregisterObserver( Observer *observer );
+
+  signals:
+    /**
+       Signal that the Calendar has been modified.
+     */
+    void calendarChanged();
+
+    /**
+       Signal that the Calendar has been saved.
+     */
+    void calendarSaved();
+
+    /**
+       Signal that the Calendar has been loaded into memory.
+     */
+    void calendarLoaded();
+
+  protected:
+    /**
+       The Observer interface. So far not implemented.
+
+       @param incidenceBase is a pointer an IncidenceBase object.
+    */
+    void incidenceUpdated( IncidenceBase *incidenceBase );
+
+    /**
+       Let Calendar subclasses set the Time Zone ID.
+
+       First parameter is a string containing a Time Zone ID, which is
+       assumed to be valid. On some systems, /usr/share/zoneinfo/zone.tab
+       may be available for reference.\n
+       @e Example: "Europe/Berlin"
+
+       @warning
+       Do Not pass an empty timeZoneId string as this may cause unintended
+       consequences when storing Incidences into the Calendar.
+    */
+    virtual void doSetTimeZoneId( const QString &/*timeZoneId*/ ) {}
+
+    /**
+       Let Calendar subclasses notify that they inserted an Incidence.
+
+       @param incidence is a pointer to the Incidence object that was inserted.
+    */
+    void notifyIncidenceAdded( Incidence *incidence );
+
+    /**
+       Let Calendar subclasses notify that they modified an Incidence.
+
+       @param incidence is a pointer to the Incidence object that was modified.
+    */
+    void notifyIncidenceChanged( Incidence *incidence );
+
+    /**
+       Let Calendar subclasses notify that they removed an Incidence.
+
+       @param incidence is a pointer to the Incidence object that was removed.
+    */
+    void notifyIncidenceDeleted( Incidence *incidence );
+
+    /**
+      @copydoc
+      CustomProperties::customPropertyUpdated()
+    */
+    virtual void customPropertyUpdated();
+
+    /**
+       Let Calendar subclasses notify that they enabled an Observer.
+
+       @param enabled if true tells the Calendar that a subclass has
+       enabled an Observer.
+    */
+    void setObserversEnabled( bool enabled );
+
+    //TODO: Move appendAlarms() and appendRecurringAlarms() from
+    //      calendarlocal here, as protected static methods
+    //      returning static Alarm::List
+
+  private:
+    /**
+       Intialize a Calendar object with starting values.
+    */
+    void init();
+
+    QString mProductId;
+    Person mOwner;
+    QString mTimeZoneId;
+    bool mLocalTime;
+
+    bool mModified;
+
+    CalFilter *mFilter;
+    CalFilter *mDefaultFilter;
+
+    QPtrList<Observer> mObservers;
+    bool mNewObserver;
+    bool mObserversEnabled;
+
+    // This list is used to put together related Todos
+    QDict<Incidence> mOrphans;
+    QDict<Incidence> mOrphanUids;
+
+    class Private;
+    Private *d;
+  };
+
+}
+
+#endif