Akonadi::Attribute Class Reference

#include <attribute.h>

Inheritance diagram for Akonadi::Attribute:

Public Types
using	List = QList<Attribute *>

Public Member Functions
virtual	~Attribute ()
virtual Attribute *	clone () const =0
virtual void	deserialize (const QByteArray &data)=0
virtual QByteArray	serialized () const =0
virtual QByteArray	type () const =0

Protected Member Functions
	Attribute (const Attribute &)=default

Detailed Description

Provides interface for custom attributes for Entity.

This class is an interface for custom attributes, that can be stored in an entity. Attributes should be meta data, e.g. ACLs, quotas etc. that are not part of the entities' data itself.

Note that attributes are per user, i.e. when an attribute is added to an entity, it only applies to the current user.

To provide custom attributes, you have to subclass from this interface and reimplement the pure virtual methods.

class SecrecyAttribute : public Akonadi::Attribute
{
    Q_GADGET
 
public:
    enum Secrecy
    {
        Public,
        Private,
        Confidential
    };
    Q_ENUM(Secrecy);
 
    SecrecyAttribute(Secrecy secrecy = Public)
        : mSecrecy(secrecy)
    {
    }
 
    void setSecrecy(Secrecy secrecy)
    {
        mSecrecy = secrecy;
    }
 
    Secrecy secrecy() const
    {
        return mSecrecy;
    }
 
    virtual QByteArray type() const
    {
        return "secrecy";
    }
 
    virtual Attribute* clone() const
    {
        return new SecrecyAttribute(mSecrecy);
    }
 
    virtual QByteArray serialized() const
    {
        switch (mSecrecy) {
        case Public:
            return "public";
        case Private:
            return "private";
        case Confidential:
            return "confidential";
        }
    }
 
    virtual void deserialize(const QByteArray &data)
    {
        if (data == "public") {
            mSecrecy = Public;
        } else if (data == "private") {
            mSecrecy = Private;
        } else if (data == "confidential") {
            mSecrecy = Confidential;
        }
    }
}

Additionally, you need to register your attribute with Akonadi::AttributeFactory for automatic deserialization during retrieving of collections or items:

AttributeFactory::registerAttribute<SecrecyAttribute>();

Third party attributes need to be registered once by each application that uses them. So the above snippet needs to be in the resource that adds the attribute, and each application that uses the resource. This may be simplified in the future.

The custom attributes can be used in the following way:

Akonadi::Item item(QStringLiteral("text/directory"));
SecrecyAttribute* attr = item.attribute<SecrecyAttribute>(Item::AddIfMissing);
attr->setSecrecy(SecrecyAttribute::Confidential);

and

Akonadi::Item item = ...
 
if (item.hasAttribute<SecrecyAttribute>()) {
  SecrecyAttribute *attr = item.attribute<SecrecyAttribute>();
 
  SecrecyAttribute::Secrecy secrecy = attr->secrecy();
  ...
}

Author

Volker Krause vkrau.nosp@m.se@k.nosp@m.de.or.nosp@m.g

Definition at line 131 of file attribute.h.

Member Typedef Documentation

List

using Akonadi::Attribute::List = QList<Attribute *>

Describes a list of attributes.

Definition at line 137 of file attribute.h.

Constructor & Destructor Documentation

~Attribute()

Attribute::~Attribute ( )

virtualdefault

Destroys this attribute.

Member Function Documentation

clone()

virtual Attribute * Akonadi::Attribute::clone ( ) const

pure virtual

Creates a copy of this attribute.

Implemented in Akonadi::CollectionAnnotationsAttribute, Akonadi::CollectionColorAttribute, Akonadi::CollectionIdentificationAttribute, Akonadi::CollectionQuotaAttribute, Akonadi::EntityAnnotationsAttribute, Akonadi::EntityDeletedAttribute, Akonadi::EntityDisplayAttribute, Akonadi::EntityHiddenAttribute, Akonadi::MDNStateAttribute, Akonadi::SpecialCollectionAttribute, and Akonadi::TagAttribute.

deserialize()

virtual void Akonadi::Attribute::deserialize ( const QByteArray & data )

pure virtual

Sets the data of this attribute, using the same encoding as returned by toByteArray().

Parameters

data	The encoded attribute data.

Implemented in Akonadi::CollectionAnnotationsAttribute, Akonadi::CollectionColorAttribute, Akonadi::CollectionIdentificationAttribute, Akonadi::CollectionQuotaAttribute, Akonadi::EntityAnnotationsAttribute, Akonadi::EntityDeletedAttribute, Akonadi::EntityDisplayAttribute, Akonadi::EntityHiddenAttribute, Akonadi::MDNStateAttribute, Akonadi::SpecialCollectionAttribute, and Akonadi::TagAttribute.

serialized()

virtual QByteArray Akonadi::Attribute::serialized ( ) const

pure virtual

Returns a QByteArray representation of the attribute which will be storaged.

This can be raw binary data, no encoding needs to be applied.

Implemented in Akonadi::CollectionAnnotationsAttribute, Akonadi::CollectionColorAttribute, Akonadi::CollectionIdentificationAttribute, Akonadi::CollectionQuotaAttribute, Akonadi::EntityAnnotationsAttribute, Akonadi::EntityDeletedAttribute, Akonadi::EntityDisplayAttribute, Akonadi::EntityHiddenAttribute, Akonadi::MDNStateAttribute, Akonadi::SpecialCollectionAttribute, and Akonadi::TagAttribute.

type()

virtual QByteArray Akonadi::Attribute::type ( ) const

pure virtual

Returns the type of the attribute.

Implemented in Akonadi::CollectionAnnotationsAttribute, Akonadi::CollectionColorAttribute, Akonadi::CollectionIdentificationAttribute, Akonadi::CollectionQuotaAttribute, Akonadi::EntityAnnotationsAttribute, Akonadi::EntityDeletedAttribute, Akonadi::EntityDisplayAttribute, Akonadi::EntityHiddenAttribute, Akonadi::MDNStateAttribute, Akonadi::SpecialCollectionAttribute, and Akonadi::TagAttribute.

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The documentation for this class was generated from the following files:

• attribute.h
• attribute.cpp