qgsrelation.h

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/***************************************************************************
    qgsrelation.h
     --------------------------------------
    Date                 : 29.4.2013
    Copyright            : (C) 2013 Matthias Kuhn
    Email                : matthias at opengis dot ch
 ***************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/
 
#ifndef QGSRELATION_H
#define QGSRELATION_H
 
#include <QList>
#include <QDomNode>
#include <QPair>
 
#include "qgis_core.h"
#include "qgsfields.h"
#include "qgsreadwritecontext.h"
#include "qgsrelationcontext.h"
 
#include "qgis_sip.h"
 
class QgsFeatureIterator;
class QgsFeature;
class QgsFeatureRequest;
class QgsAttributes;
class QgsVectorLayer;
class QgsRelationPrivate;
 
class CORE_EXPORT QgsRelation
{
    Q_GADGET
 
    Q_PROPERTY( QString id READ id WRITE setId )
    Q_PROPERTY( QgsVectorLayer *referencingLayer READ referencingLayer )
    Q_PROPERTY( QgsVectorLayer *referencedLayer READ referencedLayer )
    Q_PROPERTY( QString name READ name WRITE setName )
    Q_PROPERTY( bool isValid READ isValid )
 
  public:
 
    enum RelationStrength
    {
      Association, 
      Composition  
 
    };
 
#ifndef SIP_RUN
 
    class FieldPair : public QPair< QString, QString >
    {
      public:
        FieldPair() = default;
 
        FieldPair( const QString &referencingField, const QString &referencedField )
          : QPair< QString, QString >( referencingField, referencedField ) {}
 
        QString referencingField() const { return first; }
        QString referencedField() const { return second; }
 
        bool operator==( const FieldPair &other ) const { return first == other.first && second == other.second; }
    };
#endif
 
    QgsRelation();
    ~QgsRelation();
 
    QgsRelation( const QgsRelationContext &context );
 
    QgsRelation( const QgsRelation &other );
 
    QgsRelation &operator=( const QgsRelation &other );
 
    static QgsRelation createFromXml( const QDomNode &node, QgsReadWriteContext &context, const QgsRelationContext &relationContext = QgsRelationContext() );
 
    void writeXml( QDomNode &node, QDomDocument &doc ) const;
 
    void setId( const QString &id );
 
    void setName( const QString &name );
 
    void setStrength( RelationStrength strength );
 
    void setReferencingLayer( const QString &id );
 
    void setReferencedLayer( const QString &id );
 
    void addFieldPair( const QString &referencingField, const QString &referencedField );
 
    void addFieldPair( const FieldPair &fieldPair ) SIP_SKIP;
 
    QgsFeatureIterator getRelatedFeatures( const QgsFeature &feature ) const;
 
    QgsFeatureRequest getRelatedFeaturesRequest( const QgsFeature &feature ) const;
 
    QString getRelatedFeaturesFilter( const QgsFeature &feature ) const;
 
    QgsFeatureRequest getReferencedFeatureRequest( const QgsAttributes &attributes ) const;
 
    QgsFeatureRequest getReferencedFeatureRequest( const QgsFeature &feature ) const;
 
    QgsFeature getReferencedFeature( const QgsFeature &feature ) const;
 
    QString name() const;
 
    RelationStrength strength() const;
 
    QString id() const;
 
    void generateId();
 
    QString referencingLayerId() const;
 
    QgsVectorLayer *referencingLayer() const;
 
    QString referencedLayerId() const;
 
    QgsVectorLayer *referencedLayer() const;
 
#ifndef SIP_RUN
    QList< QgsRelation::FieldPair > fieldPairs() const;
#else
    QMap< QString, QString > fieldPairs() const;
    % MethodCode
    const QList< QgsRelation::FieldPair > &pairs = sipCpp->fieldPairs();
    sipRes = new QMap< QString, QString >();
    for ( const QgsRelation::FieldPair &pair : pairs )
    {
      sipRes->insert( pair.first, pair.second );
    }
    % End
#endif
 
    QgsAttributeList referencedFields() const;
 
    QgsAttributeList referencingFields() const;
 
    bool isValid() const;
 
    bool hasEqualDefinition( const QgsRelation &other ) const;
 
    Q_INVOKABLE QString resolveReferencedField( const QString &referencingField ) const;
 
    Q_INVOKABLE QString resolveReferencingField( const QString &referencedField ) const;
 
    void updateRelationStatus();
 
  private:
 
    mutable QExplicitlySharedDataPointer<QgsRelationPrivate> d;
 
    QgsRelationContext mContext;
};
 
// Register QgsRelation for usage with QVariant
Q_DECLARE_METATYPE( QgsRelation )
Q_DECLARE_METATYPE( QgsRelation::RelationStrength )
 
#endif // QGSRELATION_H