qgsdatadefined.h

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/***************************************************************************
    qgsdatadefined.h - Data defined container class
     --------------------------------------
    Date                 : 9-May-2013
    Copyright            : (C) 2013 by Larry Shaffer
    Email                : larrys at dakcarto dot com
 ***************************************************************************
 *                                                                         *
 *   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 QGSDATADEFINED_H
#define QGSDATADEFINED_H

#include <QStringList>
#include <QDomElement>
#include <QMap>
#include <QExplicitlySharedDataPointer>
#include "qgis.h"
#include "qgsfield.h"

class QgsExpression;
class QgsVectorLayer;
class QgsDataDefinedPrivate;


class CORE_EXPORT QgsDataDefined
{
  public:
    QgsDataDefined( bool active = false,
                    bool useexpr = false,
                    const QString& expr = QString(),
                    const QString& field = QString() );

    explicit QgsDataDefined( const QgsExpression * expression );

    explicit QgsDataDefined( const QString& string );

    QgsDataDefined( const QgsDataDefined& other );

    static QgsDataDefined* fromMap( const QgsStringMap& map, const QString& baseName = QString() );

    virtual ~QgsDataDefined();

    bool hasDefaultValues() const;

    bool isActive() const;
    void setActive( bool active );

    bool useExpression() const;
    void setUseExpression( bool use );

    QString expressionString() const;
    void setExpressionString( const QString& expr );

    // @note not available in python bindings
    QMap<QString, QVariant> expressionParams() const;
    // @note not available in python bindings
    void setExpressionParams( QMap<QString, QVariant> params );
    void insertExpressionParam( QString key, QVariant param );

    bool prepareExpression( QgsVectorLayer* layer );

    bool prepareExpression( const QgsFields &fields = QgsFields() );

    bool expressionIsPrepared() const;

    QgsExpression* expression();

    QStringList referencedColumns( QgsVectorLayer* layer );

    QStringList referencedColumns( const QgsFields& fields = QgsFields() );

    QString field() const;
    void setField( const QString& field );

    QgsStringMap toMap( const QString& baseName = QString() ) const;

    QDomElement toXmlElement( QDomDocument &document, const QString &elementName ) const;

    bool setFromXmlElement( const QDomElement& element );

    bool operator==( const QgsDataDefined &other ) const;
    bool operator!=( const QgsDataDefined &other ) const;

    QgsDataDefined& operator=( QgsDataDefined const & rhs );

  private:

    QExplicitlySharedDataPointer<QgsDataDefinedPrivate> d;

};

#endif // QGSDATADEFINED_H