• Skip to content
  • Skip to link menu
KDE 4.5 API Reference
  • KDE API Reference
  • KDE-PIM Libraries
  • Sitemap
  • Contact Us
 

akonadi

  • Akonadi
  • Akonadi::ResourceBase
Signals | Public Member Functions | Static Public Member Functions | Protected Types | Protected Slots | Protected Member Functions

Akonadi::ResourceBase Class Reference

The base class for all Akonadi resources. More...

#include <resourcebase.h>

Inheritance diagram for Akonadi::ResourceBase:
Inheritance graph
[legend]

List of all members.

Signals

void nameChanged (const QString &name)
void synchronized ()

Public Member Functions

QString name () const
void setName (const QString &name)

Static Public Member Functions

template<typename T >
static int init (int argc, char **argv)

Protected Types

enum  SchedulePriority { Prepend, AfterChangeReplay, Append }

Protected Slots

virtual void retrieveCollections ()=0
virtual bool retrieveItem (const Akonadi::Item &item, const QSet< QByteArray > &parts)=0
virtual void retrieveItems (const Akonadi::Collection &collection)=0

Protected Member Functions

 ResourceBase (const QString &id)
 ~ResourceBase ()
void cancelTask ()
void cancelTask (const QString &error)
void changeCommitted (const Item &item)
void changeCommitted (const Collection &collection)
void clearCache ()
void collectionsRetrievalDone ()
void collectionsRetrieved (const Collection::List &collections)
void collectionsRetrievedIncremental (const Collection::List &changedCollections, const Collection::List &removedCollections)
Collection currentCollection () const
Item currentItem () const
void deferTask ()
void doSetOnline (bool online)
void itemRetrieved (const Item &item)
void itemsRetrievalDone ()
void itemsRetrieved (const Item::List &items)
void itemsRetrievedIncremental (const Item::List &changedItems, const Item::List &removedItems)
void scheduleCustomTask (QObject *receiver, const char *method, const QVariant &argument, SchedulePriority priority=Append)
void setCollectionStreamingEnabled (bool enable)
void setHierarchicalRemoteIdentifiersEnabled (bool enable)
void setItemStreamingEnabled (bool enable)
void setTotalItems (int amount)
void synchronize ()
void synchronizeCollection (qint64 id)
void synchronizeCollectionTree ()
void taskDone ()

Detailed Description

The base class for all Akonadi resources.

This class should be used as a base class by all resource agents, because it encapsulates large parts of the protocol between resource agent, agent manager and the Akonadi storage.

It provides many convenience methods to make implementing a new Akonadi resource agent as simple as possible.

How to write a resource

The following provides an overview of what you need to do to implement your own Akonadi resource. In the following, the term 'backend' refers to the entity the resource connects with Akonadi, be it a single file or a remote server.

Todo:
Complete this (online/offline state management)
Basic Resource Framework

The following is needed to create a new resource:

  • A new class deriving from Akonadi::ResourceBase, implementing at least all pure-virtual methods, see below for further details.
  • call init() in your main() function.
  • a .desktop file similar to the following example
     [Desktop Entry]
     Encoding=UTF-8
     Name=My Akonadi Resource
     Type=AkonadiResource
     Exec=akonadi_my_resource
     Icon=my-icon
    
     X-Akonadi-MimeTypes=<supported-mimetypes>
     X-Akonadi-Capabilities=Resource
     X-Akonadi-Identifier=akonadi_my_resource
    
Handling PIM Items

To follow item changes in the backend, the following steps are necessary:

  • Implement retrieveItems() to synchronize all items in the given collection. If the backend supports incremental retrieval, implementing support for that is recommended to improve performance.
  • Convert the items provided by the backend to Akonadi items. This typically happens either in retrieveItems() if you retrieved the collection synchronously (not recommended for network backends) or in the result slot of the asynchronous retrieval job. Converting means to create Akonadi::Item objects for every retrieved item. It's very important that every object has its remote identifier set.
  • Call itemsRetrieved() or itemsRetrievedIncremental() respectively with the item objects created above. The Akonadi storage will then be updated automatically. Note that it is usually not necessary to manipulate any item in the Akonadi storage manually.

To fetch item data on demand, the method retrieveItem() needs to be reimplemented. Fetch the requested data there and call itemRetrieved() with the result item.

To write local changes back to the backend, you need to re-implement the following three methods:

  • itemAdded()
  • itemChanged()
  • itemRemoved() Note that these three functions don't get the full payload of the items by default, you need to change the item fetch scope of the change recorder to fetch the full payload. This can be expensive with big payloads, though.
    Once you have handled changes in these methods call changeCommitted(). These methods are called whenever a local item related to this resource is added, modified or deleted. They are only called if the resource is online, otherwise all changes are recorded and replayed as soon the resource is online again.
Handling Collections

To follow collection changes in the backend, the following steps are necessary:

  • Implement retrieveCollections() to retrieve collections from the backend. If the backend supports incremental collections updates, implementing support for that is recommended to improve performance.
  • Convert the collections of the backend to Akonadi collections. This typically happens either in retrieveCollections() if you retrieved the collection synchronously (not recommended for network backends) or in the result slot of the asynchronous retrieval job. Converting means to create Akonadi::Collection objects for every retrieved collection. It's very important that every object has its remote identifier and its parent remote identifier set.
  • Call collectionsRetrieved() or collectionsRetrievedIncremental() respectively with the collection objects created above. The Akonadi storage will then be updated automatically. Note that it is usually not necessary to manipulate any collection in the Akonadi storage manually.

To write local collection changes back to the backend, you need to re-implement the following three methods:

  • collectionAdded()
  • collectionChanged()
  • collectionRemoved() Once you have handled changes in these methods call changeCommitted(). These methods are called whenever a local collection related to this resource is added, modified or deleted. They are only called if the resource is online, otherwise all changes are recorded and replayed as soon the resource is online again.
Todo:
Convenience base class for collection-less resources

Definition at line 144 of file resourcebase.h.


Member Enumeration Documentation

enum Akonadi::ResourceBase::SchedulePriority [protected]

Describes the scheduling priority of a task that has been queued for execution.

See also:
scheduleCustomTask
Since:
4.4
Enumerator:
AfterChangeReplay 

> The task will be executed as soon as the current task has finished.

Append 

> The task is scheduled after the last ChangeReplay task in the queue

> The task will be executed after all tasks currently in the queue are finished

Definition at line 457 of file resourcebase.h.


Constructor & Destructor Documentation

Akonadi::ResourceBase::ResourceBase ( const QString &  id  )  [protected]

Creates a base resource.

Parameters:
id The instance id of the resource.
Akonadi::ResourceBase::~ResourceBase (  )  [protected]

Destroys the base resource.


Member Function Documentation

void Akonadi::ResourceBase::cancelTask (  )  [protected]

Stops the execution of the current task and continues with the next one.

void Akonadi::ResourceBase::cancelTask ( const QString &  error  )  [protected]

Stops the execution of the current task and continues with the next one.

Additionally an error message is emitted.

void Akonadi::ResourceBase::changeCommitted ( const Collection &  collection  )  [protected]

Call whenever you have successfully handled or ignored a collection change notification.

This will update the remote identifier of collection if necessary, as well as any other collection attributes. This implicitly calls changeProcessed().

Parameters:
collection The collection which changes have been handled.
void Akonadi::ResourceBase::changeCommitted ( const Item &  item  )  [protected]

Resets the dirty flag of the given item and updates the remote id.

Call whenever you have successfully written changes back to the server. This implicitly calls changeProcessed().

Parameters:
item The changed item.
void Akonadi::ResourceBase::clearCache (  )  [protected]

Call this method to remove all items and collections of the resource from the server cache.

The method should be used whenever the configuration of the resource has changed and therefor the cached items might not be valid any longer.

Since:
4.3
void Akonadi::ResourceBase::collectionsRetrievalDone (  )  [protected]

Call this method to indicate you finished synchronizing the collection tree.

This is not needed if you use the built in syncing without collection streaming and call collectionsRetrieved() or collectionRetrievedIncremental() instead. If collection streaming is enabled, call this method once all collections have been delivered using collectionsRetrieved() or collectionsRetrievedIncremental().

void Akonadi::ResourceBase::collectionsRetrieved ( const Collection::List &  collections  )  [protected]

Call this to supply the full folder tree retrieved from the remote server.

Parameters:
collections A list of collections.
See also:
collectionsRetrievedIncremental()
void Akonadi::ResourceBase::collectionsRetrievedIncremental ( const Collection::List &  changedCollections,
const Collection::List &  removedCollections 
) [protected]

Call this to supply incrementally retrieved collections from the remote server.

Parameters:
changedCollections Collections that have been added or changed.
removedCollections Collections that have been deleted.
See also:
collectionsRetrieved()
Collection Akonadi::ResourceBase::currentCollection (  )  const [protected]

Returns the collection that is currently synchronized.

Item Akonadi::ResourceBase::currentItem (  )  const [protected]

Returns the item that is currently retrieved.

void Akonadi::ResourceBase::deferTask (  )  [protected]

Stops the execution of the current task and continues with the next one.

The current task will be tried again later.

This can be used to delay the task processing until the resource has reached a safe state, e.g. login to a server succeeded.

Note:
This does not change the order of tasks so if there is no task with higher priority e.g. a custom task added with Prepend the deferred task will be processed again.
Since:
4.3
void Akonadi::ResourceBase::doSetOnline ( bool  online  )  [protected, virtual]

Inherited from AgentBase.

Reimplemented from Akonadi::AgentBase.

template<typename T >
static int Akonadi::ResourceBase::init ( int  argc,
char **  argv 
) [inline, static]

Use this method in the main function of your resource application to initialize your resource subclass.

This method also takes care of creating a KApplication object and parsing command line arguments.

Note:
In case the given class is also derived from AgentBase::Observer it gets registered as its own observer (see AgentBase::Observer), e.g. resourceInstance->registerObserver( resourceInstance );
   class MyResource : public ResourceBase
   {
     ...
   };

   int main( int argc, char **argv )
   {
     return ResourceBase::init<MyResource>( argc, argv );
   }

Reimplemented from Akonadi::AgentBase.

Definition at line 174 of file resourcebase.h.

void Akonadi::ResourceBase::itemRetrieved ( const Item &  item  )  [protected]

Call this method from retrieveItem() once the result is available.

Parameters:
item The retrieved item.
void Akonadi::ResourceBase::itemsRetrievalDone (  )  [protected]

Call this method to indicate you finished synchronizing the current collection.

This is not needed if you use the built in syncing without item streaming and call itemsRetrieved() or itemsRetrievedIncremental() instead. If item streaming is enabled, call this method once all items have been delivered using itemsRetrieved() or itemsRetrievedIncremental().

See also:
retrieveItems()
void Akonadi::ResourceBase::itemsRetrieved ( const Item::List &  items  )  [protected]

Call this method to supply the full collection listing from the remote server.

If the remote server supports incremental listing, it's strongly recommended to use itemsRetrievedIncremental() instead.

Parameters:
items A list of items.
See also:
itemsRetrievedIncremental().
void Akonadi::ResourceBase::itemsRetrievedIncremental ( const Item::List &  changedItems,
const Item::List &  removedItems 
) [protected]

Call this method to supply incrementally retrieved items from the remote server.

Parameters:
changedItems Items changed in the backend.
removedItems Items removed from the backend.
QString Akonadi::ResourceBase::name (  )  const

Returns the name of the resource.

void Akonadi::ResourceBase::nameChanged ( const QString &  name  )  [signal]

This signal is emitted whenever the name of the resource has changed.

Parameters:
name The new name of the resource.
virtual void Akonadi::ResourceBase::retrieveCollections (  )  [protected, pure virtual, slot]

Retrieve the collection tree from the remote server and supply it via collectionsRetrieved() or collectionsRetrievedIncremental().

See also:
collectionsRetrieved(), collectionsRetrievedIncremental()
virtual bool Akonadi::ResourceBase::retrieveItem ( const Akonadi::Item &  item,
const QSet< QByteArray > &  parts 
) [protected, pure virtual, slot]

Retrieve a single item from the backend.

The item to retrieve is provided as item. Add the requested payload parts and call itemRetrieved() when done.

Parameters:
item The empty item whose payload should be retrieved. Use this object when delivering the result instead of creating a new item to ensure conflict detection will work.
parts The item parts that should be retrieved.
Returns:
false if there is an immediate error when retrieving the item.
See also:
itemRetrieved()
virtual void Akonadi::ResourceBase::retrieveItems ( const Akonadi::Collection &  collection  )  [protected, pure virtual, slot]

Retrieve all (new/changed) items in collection collection.

It is recommended to use incremental retrieval if the backend supports that and provide the result by calling itemsRetrievedIncremental(). If incremental retrieval is not possible, provide the full listing by calling itemsRetrieved( const Item::List& ). In any case, ensure that all items have a correctly set remote identifier to allow synchronizing with items already existing locally. In case you don't want to use the built-in item syncing code, store the retrieved items manually and call itemsRetrieved() once you are done.

Parameters:
collection The collection whose items to retrieve.
See also:
itemsRetrieved( const Item::List& ), itemsRetrievedIncremental(), itemsRetrieved(), currentCollection()
void Akonadi::ResourceBase::scheduleCustomTask ( QObject *  receiver,
const char *  method,
const QVariant &  argument,
SchedulePriority  priority = Append 
) [protected]

Schedules a custom task in the internal scheduler.

It will be queued with all other tasks such as change replays and retrieval requests and eventually executed by calling the specified method. With the priority parameter the time of execution of the Task can be influenced.

See also:
SchedulePriority
Parameters:
receiver The object the slot should be called on.
method The name of the method (and only the name, not signature, not SLOT(...) macro), that should be called to execute this task. The method has to be a slot and take a QVariant as argument.
argument A QVariant argument passed to the method specified above. Use this to pass task parameters.
priority Priority of the task. Use this to influence the position in the execution queue.
Since:
4.4
void Akonadi::ResourceBase::setCollectionStreamingEnabled ( bool  enable  )  [protected]

Enable collection streaming, that is collections don't have to be delivered at once as result of a retrieveCollections() call but can be delivered by multiple calls to collectionsRetrieved() or collectionsRetrievedIncremental().

When all collections have been retrieved, call collectionsRetrievalDone().

Parameters:
enable true if collection streaming should be enabled, false by default
void Akonadi::ResourceBase::setHierarchicalRemoteIdentifiersEnabled ( bool  enable  )  [protected]

Indicate the use of hierarchical remote identifiers.

This means that it is possible to have two different items with the same remoteId in different Collections.

This should be called in the resource constructor as needed.

Since:
4.4
void Akonadi::ResourceBase::setItemStreamingEnabled ( bool  enable  )  [protected]

Enable item streaming.

Item streaming is disabled by default.

Parameters:
enable true if items are delivered in chunks rather in one big block.
void Akonadi::ResourceBase::setName ( const QString &  name  ) 

This method is used to set the name of the resource.

void Akonadi::ResourceBase::setTotalItems ( int  amount  )  [protected]

Call this method when you want to use the itemsRetrieved() method in streaming mode and indicate the amount of items that will arrive that way.

Deprecated:
Use setItemStreamingEnabled( true ) + itemsRetrieved[Incremental]() + itemsRetrieved() instead.
void Akonadi::ResourceBase::synchronize (  )  [protected]

This method is called whenever the resource should start synchronize all data.

void Akonadi::ResourceBase::synchronizeCollection ( qint64  id  )  [protected]

This method is called whenever the collection with the given id shall be synchronized.

void Akonadi::ResourceBase::synchronizeCollectionTree (  )  [protected]

Refetches the Collections.

void Akonadi::ResourceBase::synchronized (  )  [signal]

Emitted when a full synchronization has been completed.

void Akonadi::ResourceBase::taskDone (  )  [protected]

Indicate that the current task is finished.

Use this method from the slot called via scheduleCustomTaks(). As with all the other callbacks, make sure to either call taskDone() or cancelTask()/deferTask() on all exit paths, otherwise the resource will hang.

Since:
4.4

The documentation for this class was generated from the following file:
  • resourcebase.h

akonadi

Skip menu "akonadi"
  • Main Page
  • Modules
  • Namespace List
  • Class Hierarchy
  • Alphabetical List
  • Class List
  • File List
  • Namespace Members
  • Class Members
  • Related Pages

KDE-PIM Libraries

Skip menu "KDE-PIM Libraries"
  • akonadi
  •   contact
  •   kmime
  • kabc
  • kblog
  • kcal
  • kholidays
  • kimap
  • kioslave
  •   imap4
  •   mbox
  •   nntp
  • kldap
  • kmime
  • kontactinterface
  • kpimidentities
  • kpimtextedit
  •   richtextbuilders
  • kpimutils
  • kresources
  • ktnef
  • kxmlrpcclient
  • mailtransport
  • microblog
  • qgpgme
  • syndication
  •   atom
  •   rdf
  •   rss2
Generated for KDE-PIM Libraries by doxygen 1.7.1
This website is maintained by Adriaan de Groot and Allen Winter.
KDE® and the K Desktop Environment® logo are registered trademarks of KDE e.V. | Legal