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kdelibs/nepomuk/core/resource.h
Ivailo Monev 814163a8dc initial import
2014-11-13 01:04:59 +02:00

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/*
* This file is part of the Nepomuk KDE project.
* Copyright (C) 2006-2009 Sebastian Trueg <trueg@kde.org>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public License
* along with this library; see the file COPYING.LIB. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
#ifndef _NEPOMUK_RESOURCE_H_
#define _NEPOMUK_RESOURCE_H_
#include <QtCore/QHash>
#include <QtCore/QStringList>
#include <kurl.h>
#include "class.h"
#include "nepomuk_export.h"
namespace Nepomuk {
class ResourceManager;
class ResourceData;
class Variant;
class Tag;
class Thing;
class File;
namespace Types {
class Property;
}
enum ErrorCode {
NoError = 0,
CommunicationError, /**< A communication error, i.e. connection failure */
InvalidType,
UnknownError
};
/**
* \return A human-readble string.
*/
// FIXME: add the uri of the resource as parameter
NEPOMUK_EXPORT QString errorString( ErrorCode code );
/**
* \class Resource resource.h Nepomuk/Resource
*
* \brief Resource is the central object type in Nepomuk. It represents a piece of
* information of any kind.
*
* Resources are identified by their unique URI (which
* correlates directly with the URI in the local NEPOMUK RDF storage.
*
* Resource objects with the same URI share their data.
*
* All methods in Resource are thread-safe.
*
* See \ref hacking for details on how to use Resource.
*
* \see ResourceManager
*
* \section nepomuk_resource_file_uris Special case: file URLs
*
* \p file:/ URLs are handled as a special case in Nepomuk. Starting with KDE 4.4
* they are no longer used to identify the Nepomuk resource but only stored as
* nie:url property. All resources have \p nepomuk:/res/<UUID> URIs. The Resource
* constructors handle this automatically. Thus, one can still use file URLs to
* construct the objects. But be aware of the following example:
*
* \code
* KUrl fileUrl("file:///home/foobar/example.txt");
* Nepomuk::Resource fileRes(fileUrl);
* QUrl fileResUri = fileRes.resourceUri();
* \endcode
*
* Here \p fileUrl and \p fileResUri are NOT equal. The latter is the resource URI
* of the form \p nepomuk:/res/<UUID>.
*
* \author Sebastian Trueg <trueg@kde.org>
*/
class NEPOMUK_EXPORT Resource
{
public:
/**
* Creates an empty invalid Resource.
* An invalid resource will become valid (i.e. get a new random URI) once setProperty
* is called.
*/
Resource();
/**
* Creates an empty invalid Resource.
* An invalid resource will become valid (i.e. get a new random URI) once setProperty
* is called.
*
* \param manager The resource manager to use. This allows to mix resources from different
* managers and, thus, different models.
*
* \since 4.3
*/
Resource( ResourceManager* manager );
/**
* Copy constructor
*/
Resource( const Resource& );
/**
* Creates a new Resource object.
*
* The actual resource data is loaded on demand. Thus, it is possible to work
* with Resources as if they were in memory all the time.
*
* \param pathOrIdentifier The path to a file or an arbitrary identifier of the resource.
* The following cases are handled:
* \li A local file path is converted to a local file URL
* \li A URI which already exist in Nepomuk results in loading of that particular resource.
* \li A string which already exists as the nao:identifier of a resource results in loading
* of that particular resource.
* \li Any other string is used as nao:identifier for a new resource. This resource can
* later be loaded again by using the same identifier with this constructor.
*
* \param type The URI identifying the type of the resource. If it is empty
* Resource falls back to http://www.w3.org/2000/01/rdf-schema\#Resource or
* in case the resource already exists the type will be read from the
* store.
*
* Example:
*
* The best way to understand the path or identifier system is through tags.
* There are two ways to create a resource that represents an existing tag. The first is the
* low level one: use the unique URI of the tag with the Resource(QUrl,QUrl) constructor.
* The second one is to use this constructor with the name of the tag as its identifier:
*
* \code
* Resource myTag( "Nepomuk" );
* \endcode
*
* This will result in Resource loading the tag with nao:identifier "Nepomuk".
*/
Resource( const QString& pathOrIdentifier, const QUrl& type = QUrl() );
/**
* \overload
*
* \param manager The resource manager to use. This allows to mix resources from different
* managers and, thus, different models.
*
* \since 4.3
*/
Resource( const QString& pathOrIdentifier, const QUrl& type, ResourceManager* manager );
/**
* \deprecated use Resource( const QString&, const QUrl& )
*/
#ifndef KDE_NO_DEPRECATED
KDE_DEPRECATED Resource( const QString& pathOrIdentifier, const QString& type );
#endif
/**
* Creates a new Resource object.
*
* \param uri The URI of the resource. If no resource with this URI exists, a new one is
* created. Using an empty QUrl will result in a new resource with a random URI being created
* on the first call to setProperty.
*
* See the \ref nepomuk_resource_file_uris Special file URL handling.
*
* \param type The URI identifying the type of the resource. If it is empty
* Resource falls back to http://www.w3.org/2000/01/rdf-schema\#Resource or
* in case the resource already exists the type will be read from the
* store.
*/
Resource( const QUrl& uri, const QUrl& type = QUrl() );
/**
* \overload
*
* \param manager The resource manager to use. This allows to mix resources from different
* managers and, thus, different models.
*
* \since 4.3
*/
Resource( const QUrl& uri, const QUrl& type, ResourceManager* manager );
/**
* Constructor used internally.
*/
Resource( ResourceData* );
/**
* Destructor
*/
virtual ~Resource();
/**
* Makes this instance of Resource a copy of other.
*/
Resource& operator=( const Resource& other );
/**
* Same as operator=( Resource( uri ) )
*/
Resource& operator=( const QUrl& uri );
/**
* The Resource manager that manages this resource.
*
* \since 4.3
*/
ResourceManager* manager() const;
/**
* The URI of the resource, uniquely identifying it. This URI in most
* cases is a virtual one which has been created from a generic base
* namespace and some identifier.
*
* The most important thing to remember is that the URI of for example
* a file does not necessarily have a relation to its local path.
* (Although Nepomuk tries to keep the URI of file resources in sync
* with the file URL for convenience.)
*
* For historical reasons the method does return a URI as QString instead
* of QUrl. The value equals resourceUri().toString().
*
* \sa resourceUri(), getIdentifiers()
*
* \deprecated use resourceUri() instead
*/
#ifndef KDE_NO_DEPRECATED
KDE_DEPRECATED QString uri() const;
#endif
/**
* The URI of the resource, uniquely identifying it. This URI in most
* cases is a virtual one which has been created from a generic base
* namespace and some identifier.
*
* The most important thing to remember is that the URI of for example
* a file does not necessarily have a relation to its local path.
*
* \return The resource URI of the resource or an empty url if the
* resource does not exist() yet.
*
* \sa getIdentifiers()
*/
QUrl resourceUri() const;
/**
* The main type of the resource. Nepomuk tries hard to make this
* the type furthest down the hierarchy. In case the resource has only
* one type, this is no problem. However, if the resource has multiple
* types from different type hierarchies, there is no guarantee which
* one will be used here.
*
* For historical reasons the method does return a URI as QString instead
* of QUrl. The value equals resourceType().toString().
*
* \sa name(), hasType(), types()
*
* \deprecated use resourceType instead
*/
#ifndef KDE_NO_DEPRECATED
KDE_DEPRECATED QString type() const;
#endif
/**
* The main type of the resource. Nepomuk tries hard to make this
* the type furthest down the hierarchy. In case the resource has only
* one type, this is no problem. However, if the resource has multiple
* types from different type hierarchies, there is no guarantee which
* one will be used here.
*
* \sa name(), hasType(), types()
*/
QUrl resourceType() const;
/**
* \return The list of all stored types for this resource. This may
* also include types that lie in the same hierachy.
*
* \sa type(), hasType()
*/
QList<QUrl> types() const;
/**
* Set the types of the resource. Previous types will be overwritten.
*
* \since 4.2
*/
void setTypes( const QList<QUrl>& types );
/**
* Add a type to the list of types.
*
* \since 4.2
*/
void addType( const QUrl& type );
/**
* Check if the resource is of a certain type. The type hierarchy
* is checked including subclass relations.
*/
bool hasType( const QUrl& typeUri ) const;
/**
* The name of the class this Resource represents an object of.
* The classname is derived from the type URI (see Resource::uri).
* For a translated user readable name of the resource see
* Ontology::typeName.
*
* \sa type()
*/
QString className() const;
/**
* \deprecated Use properties()
*/
#ifndef KDE_NO_DEPRECATED
KDE_DEPRECATED QHash<QString, Variant> allProperties() const;
#endif
/**
* \return A list of all defined properties
*/
QHash<QUrl, Variant> properties() const;
/**
* Check if property identified by \a uri is defined
* for this resource.
*
* \param uri The URI identifying the property.
*
* \return true if property \a uri has a value set.
*/
bool hasProperty( const QUrl& uri ) const;
/**
* Check if the resource has a property \p p with value \p v.
*
* \since 4.5
*/
bool hasProperty( const Types::Property& p, const Variant& v ) const;
/**
* \deprecated use hasProperty( const QUrl& ) const
*/
#ifndef KDE_NO_DEPRECATED
KDE_DEPRECATED bool hasProperty( const QString& uri ) const;
#endif
/**
* Retrieve the value of property \a uri. If the property is not defined for
* this resource an invalid, empty Variant object is returned.
*
* \param uri The URI identifying the property.
*/
Variant property( const QUrl& uri ) const;
/**
* \deprecated use property( const QUrl& ) const
*/
#ifndef KDE_NO_DEPRECATED
KDE_DEPRECATED Variant property( const QString& uri ) const;
#endif
/**
* Set a property of the resource.
*
* \param uri The URI identifying the property.
* \param value The value of the property (i.e. the object of the RDF triple(s))
*/
void setProperty( const QUrl& uri, const Variant& value );
/**
* Add a property value to the existing values.
*
* \param uri The URI identifying the property.
* \param value The value of the property (i.e. the object of the RDF triple(s))
*
* \since 4.3
*/
void addProperty( const QUrl& uri, const Variant& value );
/**
* \deprecated use setProperty( const QUrl& )
*/
#ifndef KDE_NO_DEPRECATED
KDE_DEPRECATED void setProperty( const QString& uri, const Variant& value );
#endif
/**
* Remove property \a uri from this resource object.
*
* \param uri The URI identifying the property.
*/
void removeProperty( const QUrl& uri );
/**
* Remove \a value from property \a uri of this resource object.
*
* \param uri The URI identifying the property.
* \param value The value to remove
*
* \since 4.3
*/
void removeProperty( const QUrl& uri, const Variant& value );
/**
* \deprecated use removeProperty( const QUrl& )
*/
#ifndef KDE_NO_DEPRECATED
KDE_DEPRECATED void removeProperty( const QString& uri );
#endif
/**
* Remove this resource completely.
* CAUTION: After calling this method the resource will have been removed from the store
* without any trace.
*/
void remove();
/**
* \return true if this resource (i.e. the uri of this resource) exists in the local
* NEPOMUK RDF store.
*/
bool exists() const;
/**
* \return true if this Resource object is valid, i.e. has a proper URI and type and
* can be synced with the local NEPOMUK RDF store.
*
* An invalid resource will become valid (i.e. get a new random URI) once setProperty
* is called.
*/
bool isValid() const;
/**
* Tries very hard to find a suitable human-readable label for this resource.
* It looks for properties such as nao:prefLabel, rdfs:label, or nao:identifier,
* or even the fileName of File resources.
*
* \return A human readable label or if all fails the URI of the resource.
*/
QString genericLabel() const;
/**
* Tries very hard to find a suitable human-readable description of the resource.
* This description is supposed to be longer than genericLabel() and includes such properties
* as nao:description, xesam:comment, rdfs:comment
*
* \return A human readable description of the resource or an empty string if none
* could be found.
*/
QString genericDescription() const;
/**
* Tries very hard to find an icon suitable for this resource.
*
* \return An icon name to be used with KIcon or an empty string if none was found.
*/
QString genericIcon() const;
/**
* Get or create the PIMO thing that relates to this resource. If this resource
* itself is a pimo:Thing, a reference to this is returned. If a pimo:Thing exists
* with has as occurrence this resource, the thing is returned. Otherwise a new thing
* is created.
*
* \since 4.2
*/
Thing pimoThing();
/**
* Operator to compare two Resource objects.
*/
bool operator==( const Resource& ) const;
/**
* Operator to compare two Resource objects.
*
* \since 4.4
*/
bool operator!=( const Resource& ) const;
/**
* Get property 'description'. Everything can be annotated with
* a simple string comment.
*/
QString description() const;
/**
* Set property 'description'. Everything can be annotated with
* a simple string comment.
*/
void setDescription( const QString& value );
/**
* \return The URI of the property 'description'.
*/
static QString descriptionUri();
/**
* Get property 'identifier'.
*/
QStringList identifiers() const;
/**
* Set property 'identifier'.
*/
void setIdentifiers( const QStringList& value );
/**
* Add a value to property 'identifier'.
*/
void addIdentifier( const QString& value );
/**
* \return The URI of the property 'identifier'.
*/
static QString identifierUri();
/**
* Get property 'altLabel'.
*/
QStringList altLabels() const;
/**
* Set property 'altLabel'.
*/
void setAltLabels( const QStringList& value );
/**
* Add a value to property 'altLabel'.
*/
void addAltLabel( const QString& value );
/**
* \return The URI of the property 'altLabel'.
*/
static QString altLabelUri();
/**
* Get property 'annotation'.
*/
QList<Resource> annotations() const;
/**
* Set property 'annotation'.
*/
void setAnnotations( const QList<Resource>& value );
/**
* Add a value to property 'annotation'.
*/
void addAnnotation( const Resource& value );
/**
* \return The URI of the property 'annotation'.
*/
static QString annotationUri();
/**
* Get property 'Tag'. Each Resource can be tagged with an arbitrary
* number of Tags. This allows a simple grouping of resources.
*/
QList<Tag> tags() const;
/**
* Set property 'Tag'. Each Resource can be tagged with an arbitrary
* number of Tags. This allows a simple grouping of resources.
*/
void setTags( const QList<Tag>& value );
/**
* Add a value to property 'Tag'. Each Resource can be tagged with
* an arbitrary number of Tags. This allows a simple grouping of
* resources.
*/
void addTag( const Tag& value );
/**
* \return The URI of the property 'Tag'.
*/
static QString tagUri();
/**
* Get property 'Topic'.
*/
QList<Resource> topics() const;
/**
* Set property 'Topic'.
*/
void setTopics( const QList<Resource>& value );
/**
* Add a value to property 'Topic'.
*/
void addTopic( const Resource& value );
/**
* \return The URI of the property 'Topic'.
*/
static QString topicUri();
/**
* Get property 'isTopicOf'.
*/
QList<Resource> isTopicOfs() const;
/**
* Set property 'isTopicOf'.
*/
void setIsTopicOfs( const QList<Resource>& value );
/**
* Add a value to property 'isTopicOf'.
*/
void addIsTopicOf( const Resource& value );
/**
* \return The URI of the property 'isTopicOf'.
*/
static QString isTopicOfUri();
/**
* Get property 'isRelated'.
*/
QList<Resource> isRelateds() const;
/**
* Set property 'isRelated'.
*/
void setIsRelateds( const QList<Resource>& value );
/**
* Add a value to property 'isRelated'.
*/
void addIsRelated( const Resource& value );
/**
* \return The URI of the property 'isRelated'.
*/
static QString isRelatedUri();
/**
* Get property 'label'.
*/
QString label() const;
/**
* Set property 'label'.
*/
void setLabel( const QString& value );
/**
* \return The URI of the property 'label'.
*/
static QString labelUri();
/**
* Get property 'Rating'.
*/
quint32 rating() const;
/**
* Set property 'Rating'.
*/
void setRating( const quint32& value );
/**
* \return The URI of the property 'Rating'.
*/
static QString ratingUri();
/**
* Get property 'Symbol'. Each resource can have a symbol assigned.
* For now this is a simple string which can either be the path to
* an actual pixmap file or just the name of an icon as defined by
* the freedesktop.org standard.
*/
QStringList symbols() const;
/**
* Set property 'Symbol'. Each resource can have a symbol assigned.
* For now this is a simple string which can either be the path to
* an actual pixmap file or just the name of an icon as defined by
* the freedesktop.org standard.
*/
void setSymbols( const QStringList& value );
/**
* Add a value to property 'Symbol'. Each resource can have a symbol
* assigned. For now this is a simple string which can either be
* the path to an actual pixmap file or just the name of an icon as
* defined by the freedesktop.org standard.
*/
void addSymbol( const QString& value );
/**
* \return The URI of the property 'Symbol'.
*/
static QString symbolUri();
/**
* Get all resources that have this resource set as property 'annotation'.
* \sa ResourceManager::allResourcesWithProperty
*/
QList<Resource> annotationOf() const;
/**
* Get all resources that have this resource set as property 'isRelated'.
* \sa ResourceManager::allResourcesWithProperty
*/
QList<Resource> isRelatedOf() const;
/**
* Retrieve a list of all available Resource resources. This list
* consists of all resource of type Resource that are stored in
* the local Nepomuk meta data storage and any changes made locally.
* Be aware that in some cases this list can get very big. Then it
* might be better to use libKNep directly.
*
* \sa ResourceManager::allResources
*
* \warning This list will be very big. Usage of this method is
* discouraged. Use Query::QueryServiceClient in combination with an
* empty Query::Query instead.
*/
static QList<Resource> allResources();
/**
* \return The usage count stored for this resource.
*
* \sa increaseUsageCount()
*
* \since 4.5
*/
int usageCount() const;
/**
* Increase the usage count of this resource and also
* update the last used date to the current date and time.
*
* \since 4.5
*/
void increaseUsageCount();
/**
* \return \p true if this resource represents a file. Use toFile() to retrieve the
* corresponding file resource which provides convinience methods to handle file
* resources.
*
* \since 4.6
*/
bool isFile() const;
/**
* Convert this resource into a File resource to have access to the convinience methods
* provided by the File class.
*
* \since 4.6
*/
File toFile() const;
/**
* Allows to quickly load a resource from its resource URI without any
* additional checks. This is mostly used for optimized code within Nepomuk.
*
* In most situations the construtor Resource( QUrl, QUrl ) is better suited.
*
* \since 4.5
*/
static Resource fromResourceUri( const KUrl& uri, const Nepomuk::Types::Class& type = Nepomuk::Types::Class(), ResourceManager* manager = 0 );
private:
/**
* Determines the final ResourceData and updates m_data if
* necessary. This will call ResourceData::determineUri()
* and optionally merge with already loaded ResourceData
* instances representing the same resource.
*/
void determineFinalResourceData() const;
ResourceData* m_data;
class Private;
Private* d; // unused
friend class ResourceData;
};
NEPOMUK_EXPORT uint qHash( const Resource& res );
}
#endif
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