qgsrelation.h

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/***************************************************************************
    qgsrelation.h
     --------------------------------------
    Date                 : 29.4.2013
    Copyright            : (C) 2013 Matthias Kuhn
    Email                : matthias dot kuhn at gmx 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 "qgsfield.h"
#include "qgsfeatureiterator.h"

class QgsVectorLayer;

class CORE_EXPORT QgsRelation
{
  public:
    class FieldPair : public QPair< QString, QString >
    {
      public:
        FieldPair()
            : QPair< QString, QString >() {}

        FieldPair( QString referencingField, QString referencedField )
            : QPair< QString, QString >( referencingField, referencedField ) {}

        const QString& referencingField() const { return first; }
        const QString& referencedField() const { return second; }
    };

    QgsRelation();

    static QgsRelation createFromXML( const QDomNode& node );

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

    void setRelationId( QString id );

    void setRelationName( QString name );

    void setReferencingLayer( QString id );

    void setReferencedLayer( QString id );

    void addFieldPair( QString referencingField, QString referencedField );

    void addFieldPair( FieldPair fieldPair );

    QgsFeatureIterator getRelatedFeatures( const QgsFeature& feature ) const;

    QgsFeatureRequest getRelatedFeaturesRequest( const QgsFeature& feature ) const;

    const QString name() const;

    const QString& id() const;

    QString referencingLayerId() const;

    QgsVectorLayer* referencingLayer() const;

    QString referencedLayerId() const;

    QgsVectorLayer* referencedLayer() const;

    QList< FieldPair > fieldPairs() const;

    bool isValid() const;

  protected:
    void updateRelationStatus();
    void runChecks();

  private:
    QString mRelationId;
    QString mRelationName;
    QString mReferencingLayerId;
    QgsVectorLayer* mReferencingLayer;
    QString mReferencedLayerId;
    QgsVectorLayer* mReferencedLayer;
    QList< FieldPair > mFieldPairs;

    bool mValid;
};

// Register QgsRelation for usage with QVariant
Q_DECLARE_METATYPE( QgsRelation )

#endif // QGSRELATION_H