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/*
Copyright (c) 2006-2008 Volker Krause <vkrause@kde.org>
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 AKONADI_TRANSACTIONSEQUENCE_H
#define AKONADI_TRANSACTIONSEQUENCE_H
#include "akonadi_export.h"
#include <akonadi/job.h>
namespace Akonadi {
class TransactionSequencePrivate;
/**
* @short Base class for jobs that need to run a sequence of sub-jobs in a transaction.
*
* As soon as the first subjob is added, the transaction is started.
* As soon as the last subjob has successfully finished, the transaction is committed.
* If any subjob fails, the transaction is rolled back.
*
* Alternatively, a TransactionSequence object can be used as a parent object
* for a set of jobs to achieve the same behaviour without subclassing.
*
* Example:
*
* @code
*
* // Delete a couple of items inside a transaction
* Akonadi::TransactionSequence *transaction = new Akonadi::TransactionSequence;
* connect( transaction, SIGNAL( result( KJob* ) ), SLOT( transactionFinished( KJob* ) ) );
*
* const Akonadi::Item::List items = ...
*
* foreach ( const Akonadi::Item &item, items ) {
* new Akonadi::ItemDeleteJob( item, transaction );
* }
*
* ...
*
* MyClass::transactionFinished( KJob *job )
* {
* if ( job->error() )
* qDebug() << "Error occurred";
* else
* qDebug() << "Items deleted successfully";
* }
*
* @endcode
*
* @author Volker Krause <vkrause@kde.org>
*/
class AKONADI_EXPORT TransactionSequence : public Job
{
Q_OBJECT
public:
/**
* Creates a new transaction sequence.
*
* @param parent The parent object.
*/
explicit TransactionSequence( QObject *parent = 0 );
/**
* Destroys the transaction sequence.
*/
~TransactionSequence();
/**
* Commits the transaction as soon as all pending sub-jobs finished successfully.
*/
void commit();
/**
* Rolls back the current transaction as soon as possible.
* You only need to call this method when you want to roll back due to external
* reasons (e.g. user cancellation), the transaction is automatically rolled back
* if one of its subjobs fails.
* @since 4.5
*/
void rollback();
/**
* Sets which job of the sequence might fail without rolling back the
* complete transaction.
*
* @since 4.5
*/
void setIgnoreJobFailure( KJob *job );
/**
* Disable automatic committing.
* Use this when you want to add jobs to this sequence after execution
* has been started, usually that is outside of the constructor or the
* method that creates this transaction sequence.
* @note Calling this method after execution of this job has been started
* has no effect.
* @param enable @c true to enable autocommitting (default), @c false to disable it
* @since 4.5
*/
void setAutomaticCommittingEnabled( bool enable );
protected:
bool addSubjob( KJob* job );
void doStart();
protected Q_SLOTS:
void slotResult( KJob *job );
private:
Q_DECLARE_PRIVATE( TransactionSequence )
//@cond PRIVATE
Q_PRIVATE_SLOT( d_func(), void commitResult(KJob*) )
Q_PRIVATE_SLOT( d_func(), void rollbackResult(KJob*) )
//@endcond
};
}
#endif
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