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/*
Copyright 2009 Ingo Klöcker <[email protected]>
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.
*/
#ifndef KCAL_COMPARISONVISITOR_H
#define KCAL_COMPARISONVISITOR_H
#include "incidencebase.h"
namespace KCal {
/**
Helper for type correct comparison of incidences via pointers.
This class provides a way of correctly comparing one incidence to another,
given two IncidenceBase derived pointers. It effectively provides a virtual
comparison method which first type checks the two pointers to ensure they
reference the same incidence type, before performing the comparison.
Usage example:
@code
KCal::Incidence *incidence; // assume this is set somewhere else
KCal::Incidence *referenceIncidence; // assume this is set somewhere else
KCal::ComparisonVisitor visitor;
// compare
if ( visitor.compare( incidence, referenceIncidence ) ) {
// incidence and referenceIncidence point to identical incidences
}
@endcode
@author Ingo Klöcker <[email protected]>
*/
class ComparisonVisitor : public IncidenceBase::Visitor
{
public:
/**
Creates a visitor instance.
*/
ComparisonVisitor();
/**
Destroys the instance.
*/
virtual ~ComparisonVisitor();
/**
Compares the incidence referenced by @p incidence to the incidence
referenced by @p reference. Returns true, if the incidence referenced
by @p incidence is identical to the incidence referenced by @p reference.
Also returns true, if @p incidence and @p reference are both @c 0.
Basically it is a virtual equivalent of
@code
*incidence == *reference
@endcode
@param incidence pointer to the incidence to compare with the reference incidence
@param reference pointer to the reference incidence
@return @c true if the two incidences are identical or both @c 0
*/
bool compare( IncidenceBase *incidence, const IncidenceBase *reference );
/**
Compares the event referenced by @p event to the incidence passed to
compare().
@return @c true if the event is identical to the reference incidence
*/
virtual bool visit( Event *event );
/**
Compares the todo referenced by @p todo to the incidence passed to
compare().
@return @c true if the todo is identical to the reference incidence
*/
virtual bool visit( Todo *todo );
/**
Compares the journal referenced by @p journal to the incidence passed to
compare().
@return @c true if the journal is identical to the reference incidence
*/
virtual bool visit( Journal *journal );
/**
Compares the freebusy object referenced by @p freebusy to the incidence passed to
compare().
@return @c true if the freebusy object is identical to the reference incidence
*/
virtual bool visit( FreeBusy *freebusy );
private:
//@cond PRIVATE
class Private;
Private *const d;
//@endcond
};
}
#endif // KCAL_COMPARISONVISITOR_H
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