qgspolymorphicrelation.h

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/***************************************************************************
    qgspolymorphicrelation.h
     --------------------------------------
    Date                 : December 2020
    Copyright            : (C) 2020 Ivan Ivanov
    Email                : ivan 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 QGSPOLYMORPHICRELATION_H
#define QGSPOLYMORPHICRELATION_H
 
#include "qgis_core.h"
#include "qgis_sip.h"
#include "qgsfields.h"
#include "qgsreadwritecontext.h"
#include "qgsrelation.h"
#include "qgsrelationcontext.h"
 
#include <QDomNode>
#include <QList>
#include <QPair>
 
class QgsFeatureIterator;
class QgsFeature;
class QgsFeatureRequest;
class QgsAttributes;
class QgsVectorLayer;
class QgsPolymorphicRelationPrivate;
class QgsExpressionContext;

class CORE_EXPORT QgsPolymorphicRelation
{
    Q_GADGET
 
    Q_PROPERTY( QString id READ id WRITE setId )
    Q_PROPERTY( QgsVectorLayer *referencingLayer READ referencingLayer )
    Q_PROPERTY( QString referencedLayerField READ referencedLayerField )
    Q_PROPERTY( QString referencedLayerExpression READ referencedLayerExpression )
    Q_PROPERTY( QString name READ name WRITE setName )
    Q_PROPERTY( bool isValid READ isValid )
 
  public:
    QgsPolymorphicRelation();
    ~QgsPolymorphicRelation();

    QgsPolymorphicRelation( const QgsRelationContext &context );

    QgsPolymorphicRelation( const QgsPolymorphicRelation &other );
    SIP_SKIP QgsPolymorphicRelation( QgsPolymorphicRelation &&other );

    QgsPolymorphicRelation &operator=( const QgsPolymorphicRelation &other );
    QgsPolymorphicRelation &operator=( QgsPolymorphicRelation &&other );
 
    // TODO QGIS 5.0 -- Remove the deprecated createFromXml method without the relationContext parameter
    Q_DECL_DEPRECATED static QgsPolymorphicRelation createFromXml( const QDomNode &node, QgsReadWriteContext &context ) SIP_DEPRECATED;

    static QgsPolymorphicRelation createFromXml( const QDomNode &node, QgsReadWriteContext &context, const QgsRelationContext &relationContext );

    void writeXml( QDomNode &node, QDomDocument &doc ) const;

    void setId( const QString &id );

    void setName( const QString &name );

    void setReferencingLayer( const QString &id );

    void addFieldPair( const QString &referencingField, const QString &referencedField );

    void addFieldPair( const QgsRelation::FieldPair &fieldPair ) SIP_SKIP;

    QString name() const;

    QString id() const;

    void generateId();

    QString referencingLayerId() const;

    QgsVectorLayer *referencingLayer() const;

#ifndef SIP_RUN
    QList< QgsRelation::FieldPair > fieldPairs() const;
#else
    // clang-format off
    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
// clang-format on
#endif

    QgsAttributeList referencedFields( const QString &layerId ) const;

    QgsAttributeList referencingFields() const;

    bool isValid() const;

    bool hasEqualDefinition( const QgsPolymorphicRelation &other ) const;

    void updateRelationStatus();

    void setReferencedLayerField( const QString &referencedLayerField );

    QString referencedLayerField() const;

    void setReferencedLayerExpression( const QString &expression );

    QString referencedLayerExpression() const;

    void setReferencedLayerIds( const QStringList &childRelationIds );

    QStringList referencedLayerIds() const;

    QList<QgsRelation> generateRelations() const;

    QString layerRepresentation( const QgsVectorLayer *layer ) const;

    Qgis::RelationshipStrength strength() const;

    void setRelationStrength( Qgis::RelationshipStrength relationStrength );
 
  private:
    friend class QgsRelationManager;

    QString upgradeGeneratedRelationId( const QString &oldRelationId ) const;
 
    QExplicitlySharedDataPointer<QgsPolymorphicRelationPrivate> d;
 
    QgsRelationContext mContext;
};
 
// Register QgsPolymorphicRelation for usage with QVariant
Q_DECLARE_METATYPE( QgsPolymorphicRelation )
 
#endif // QGSPOLYMORPHICRELATION_H