KDE 4.9 PyKDE API Reference
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";
}
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 | |||
| ) |
