KDE 4.5 PyKDE API Reference

- KDE's Python API

# ItemSerializerPlugin Class Reference

`from PyKDE4.akonadi import *`

Subclasses: Akonadi.ItemSerializerPluginV2
Namespace: Akonadi

## Detailed Description

Abstract class:
  This class can be used as a base class for new classes, but can not be instantiated directly.

The base class for item type serializer plugins.

Serializer plugins convert between the payload of Akonadi.Item objects and a textual or binary representation of the actual content data. This allows to easily add support for new types to Akonadi.

The following example shows how to implement a serializer plugin for a new data type PimNote.

The PimNote data structure:

     typedef struct {
       QString author;
       QDateTime dateTime;
       QString text;
     } PimNote;

The serializer plugin code:

     #include <QtCore/qplugin.h>

     class SerializerPluginPimNote : public QObject, public Akonadi.ItemSerializerPlugin
     {
       Q_OBJECT
       Q_INTERFACES( Akonadi.ItemSerializerPlugin )

       public:
         bool deserialize( Akonadi.Item& item, const QByteArray& label, QIODevice& data, int version )
         {
           // we don't handle versions in this example
           Q_UNUSED( version );

           // we work only on full payload
           if ( label != Akonadi.Item.FullPayload )
             return false;

           QDataStream stream( &data );

           PimNote note;
           stream >> note.author;
           stream >> note.dateTime;
           stream >> note.text;

           item.setPayload<PimNote>( note );

           return true;
         }

         void serialize( const Akonadi.Item& item, const QByteArray& label, QIODevice& data, int &version )
         {
           // we don't handle versions in this example
           Q_UNUSED( version );

           if ( label != Akonadi.Item.FullPayload || !item.hasPayload<PimNote>() )
             return;

           QDataStream stream( &data );

           PimNote note = item.payload<PimNote>();

           stream << note.author;
           stream << note.dateTime;
           stream << note.text;
         }
     };

     Q_EXPORT_PLUGIN2( akonadi_serializer_pimnote, SerializerPluginPimNote )

The desktop file:

     [Misc]
     Name=Pim Note Serializer
     Comment=An Akonadi serializer plugin for note objects

     [Plugin]
     Type=application/x-pimnote
     X-KDE-Library=akonadi_serializer_pimnote

Author:
  Till Adam <adam@kde.org>, Volker Krause <vkrause@kde.org>

## Methods
bool | deserialize (self, Akonadi.Item item, QByteArray label, QIODevice data, int version)
QSet | parts (self, Akonadi.Item item)
| serialize (self, Akonadi.Item item, QByteArray label, QIODevice data, int version)

## Method Documentation

bool deserialize | ( | self, |
|  | Akonadi.Item | item,
|  | QByteArray | label,
|  | QIODevice | data,
|  | int | version
| ) |  |  |

Abstract method:
  This method is abstract and can be overridden but not called directly.

Converts serialized item data provided in data into payload for item.

Parameters:

  | item | The item to which the payload should be added. It is guaranteed to have a mime type matching one of the supported mime types of this plugin. However it might contain a unsuited payload added manually by the application developer. Verifying the payload type in case a payload is already available is recommended therefore.
  | label | The part identifier of the part to deserialize. label might be an unsupported item part, return false if this is the case.
  | data | A QIODevice providing access to the serialized data. The QIODevice is opened in read-only mode and positioned at the beginning. The QIODevice is guaranteed to be valid.
  | version | The version of the data format as set by the user in serialize() or 0 (default).

Returns:
  false if the specified part is not supported by this plugin, true if the part could be de-serialized successfully.

QSet parts | ( | self, |
|  | Akonadi.Item | item
| ) |  |  |

Returns a list of available parts for the given item payload. The default implementation returns Item.FullPayload if a payload is set.

Parameters:

  | item | The item.

serialize | ( | self, |
|  | Akonadi.Item | item,
|  | QByteArray | label,
|  | QIODevice | data,
|  | int | version
| ) |  |  |

Abstract method:
  This method is abstract and can be overridden but not called directly.

Convert the payload object provided in item into its serialzed form into data.

Parameters:

  | item | The item which contains the payload. It is guaranteed to have a mimetype matching one of the supported mimetypes of this plugin as well as the existence of a payload object. However it might contain an unsupported payload added manually by the application developer. Verifying the payload type is recommended therefore.
  | label | The part identifier of the part to serialize. label will be one of the item parts returned by parts().
  | data | The QIODevice where the serialized data should be written to. The QIODevice is opened in write-only mode and positioned at the beginning. The QIODevice is guaranteed to be valid.
  | version | The version of the data format. Can be set by the user to handle different versions.