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/*
CharmCommand.h
This file is part of Charm, a task-based time tracking application.
Copyright (C) 2007-2018 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com
Author: Mirko Boehm <mirko.boehm@kdab.com>
Author: Frank Osterfeld <frank.osterfeld@kdab.com>
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.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef CHARMCOMMAND_H
#define CHARMCOMMAND_H
#include <QObject>
class View;
class Controller;
class CommandEmitterInterface;
/** CharmCommand encapsulates a command the view sends to the controller.
A command is able to, for example, set the hour glass cursor on
creation and restore the previous cursor on deletion, if it can be
executed without user interaction.
CharmCommand is the implementation of the command pattern in
Charm. It holds the complete state of the requested operation. When the
operation has finished, the object has to be deleted.
The QObject parent has to implement the CommandEmitterInterface.
Commands cannot be copied or assigned. After creating them, the
View will send the
command object to the controller. The controller will execute the
necessary operations, and send the command back to the View.
Objects that initiate view actions and therefore issue there own
commands need to relay those to the view (relayCommand()).
The View will call prepare() on the command before it is send to
the controller.
execute() is called by the controller.
finalize() is called by the view after the controller has returned
the command to the view.
*/
class CharmCommand : public QObject
{
Q_OBJECT
public:
explicit CharmCommand(const QString &description, QObject *parent = nullptr);
~CharmCommand() override;
QString description() const;
virtual bool prepare() = 0;
virtual bool execute(Controller *controller) = 0;
virtual bool rollback(Controller *controller);
virtual bool finalize() = 0;
CommandEmitterInterface *owner() const;
//used by UndoCharmCommandWrapper to forward signal firing
//forwards to emitExecute/emitRollback/emitRequestSlotEventIdChanged
void requestExecute();
void requestRollback();
void requestSlotEventIdChanged(int oldId, int newId);
//notify CharmCommands in a QUndoStack that an event ID has changed
virtual void eventIdChanged(int, int)
{
}
Q_SIGNALS:
void emitExecute(CharmCommand *);
void emitRollback(CharmCommand *);
void emitSlotEventIdChanged(int, int);
protected:
void showInformation(const QString &title, const QString &message);
void showCritical(const QString &title, const QString &message);
private:
CharmCommand(const CharmCommand &); // disallow copying
CommandEmitterInterface *m_owner = nullptr;
const QString m_description;
};
#endif
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