KDE 4.9 PyKDE API Reference

- KDE's Python API

# TransactionSequence Class Reference

`from PyKDE4.akonadi import *`

Inherits: Akonadi.Job → KCompositeJob → KJob → QObject
Subclasses: Akonadi.SpecialCollectionsRequestJob
Namespace: Akonadi

## Detailed Description

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:

     // 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";
     }

Author:
  Volker Krause <vkrause@kde.org>

## Methods

| __init__ (self, QObject parent=0)
bool | addSubjob (self, KJob job)
| commit (self)
| doStart (self)
| rollback (self)
| setAutomaticCommittingEnabled (self, bool enable)
| setIgnoreJobFailure (self, KJob job)
| slotResult (self, KJob job)

## Method Documentation

__init__ | ( | self, |
|  | QObject | parent=0
| ) |  |  |

Creates a new transaction sequence.

Parameters:

  | parent | The parent object.

bool addSubjob | ( | self, |
|  | KJob | job
| ) |  |  |

commit | ( |  | self ) |

Commits the transaction as soon as all pending sub-jobs finished successfully.

doStart | ( |  | self ) |

rollback | ( |  | self ) |

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

setAutomaticCommittingEnabled | ( | self, |
|  | bool | enable
| ) |  |  |

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.

Parameters:

  | enable | true to enable autocommitting (default), false to disable it

Since:
  4.5

setIgnoreJobFailure | ( | self, |
|  | KJob | job
| ) |  |  |

Sets which job of the sequence might fail without rolling back the complete transaction.

Since:
  4.5

slotResult | ( | self, |
|  | KJob | job
| ) |  |  |