A container class for data source field mapping or expression. More...

#include <qgsdatadefined.h>

Public Member Functions
	QgsDataDefined (bool active=false, bool useexpr=false, const QString &expr=QString(), const QString &field=QString())
	Construct a new data defined object. More...

	QgsDataDefined (const QgsExpression *expression)
	Construct a new data defined object, analysing the expression to determine if it's a simple field reference or an expression. More...

	QgsDataDefined (const QString &string)
	Construct a new data defined object, analysing the string to determine if it's a simple field reference or an expression. More...

	QgsDataDefined (const QgsDataDefined &other)
	Copy constructor. More...

virtual	~QgsDataDefined ()

QgsExpression *	expression ()

bool	expressionIsPrepared () const
	Returns whether the data defined object's expression is prepared. More...

QMap< QString, QVariant >	expressionParams () const

QString	expressionString () const

QString	field () const

bool	hasDefaultValues () const
	Returns whether the data defined container is set to all the default values, ie, disabled, with empty expression and no assigned field. More...

void	insertExpressionParam (QString key, QVariant param)

bool	isActive () const

bool	operator!= (const QgsDataDefined &other) const

QgsDataDefined &	operator= (QgsDataDefined const &rhs)
	Assignment operator. More...

bool	operator== (const QgsDataDefined &other) const

bool	prepareExpression (QgsVectorLayer *layer)
	Prepares the expression using a vector layer. More...

bool	prepareExpression (const QgsFields &fields=QgsFields())
	Prepares the expression using a fields collection. More...

QStringList	referencedColumns (QgsVectorLayer *layer)
	Returns the columns referenced by the QgsDataDefined. More...

QStringList	referencedColumns (const QgsFields &fields=QgsFields())
	Returns the columns referenced by the QgsDataDefined. More...

void	setActive (bool active)

void	setExpressionParams (QMap< QString, QVariant > params)

void	setExpressionString (const QString &expr)

void	setField (const QString &field)

bool	setFromXmlElement (const QDomElement &element)
	Sets the properties of the data defined container from an XML element. More...

void	setUseExpression (bool use)

QgsStringMap	toMap (const QString &baseName=QString()) const
	Encodes the QgsDataDefined into a string map. More...

QDomElement	toXmlElement (QDomDocument &document, const QString &elementName) const
	Returns a DOM element containing the properties of the data defined container. More...

bool	useExpression () const

Static Public Member Functions
static QgsDataDefined *	fromMap (const QgsStringMap &map, const QString &baseName=QString())
	Creates a QgsDataDefined from a decoded QgsStringMap. More...

Detailed Description

A container class for data source field mapping or expression.

Note: QgsDataDefined objects are implicitly shared.

Definition at line 36 of file qgsdatadefined.h.

Constructor & Destructor Documentation

QgsDataDefined::QgsDataDefined	(	bool	active = `false`,
		bool	useexpr = `false`,
		const QString &	expr = `QString()`,
		const QString &	field = `QString()`
	)

Construct a new data defined object.

Parameters

active	Whether the current data defined is active
useexpr	Whether to use expression instead of field
expr	Expression string
field	Field name string

Definition at line 24 of file qgsdatadefined.cpp.

QgsDataDefined::QgsDataDefined ( const QgsExpression * expression )

explicit

Construct a new data defined object, analysing the expression to determine if it's a simple field reference or an expression.

Parameters

expression can be null

Definition at line 32 of file qgsdatadefined.cpp.

QgsDataDefined::QgsDataDefined ( const QString & string )

explicit

Construct a new data defined object, analysing the string to determine if it's a simple field reference or an expression.

Parameters

string field reference or an expression, can be empty

Note: added in QGIS 2.9

Definition at line 70 of file qgsdatadefined.cpp.

QgsDataDefined::QgsDataDefined ( const QgsDataDefined & other )

Copy constructor.

Note that copies of data defined objects with expressions will not be prepared.

Definition at line 42 of file qgsdatadefined.cpp.

QgsDataDefined::~QgsDataDefined ( )

virtual

Definition at line 82 of file qgsdatadefined.cpp.

Member Function Documentation

QgsExpression * QgsDataDefined::expression ( )

Definition at line 211 of file qgsdatadefined.cpp.

bool QgsDataDefined::expressionIsPrepared ( ) const

Returns whether the data defined object's expression is prepared.

Returns: true if expression is prepared

Definition at line 206 of file qgsdatadefined.cpp.

QMap< QString, QVariant > QgsDataDefined::expressionParams ( ) const

Definition at line 138 of file qgsdatadefined.cpp.

QString QgsDataDefined::expressionString ( ) const

Definition at line 121 of file qgsdatadefined.cpp.

QString QgsDataDefined::field ( ) const

Definition at line 255 of file qgsdatadefined.cpp.

QgsDataDefined * QgsDataDefined::fromMap	(	const QgsStringMap &	map,
		const QString &	baseName = `QString()`
	)

static

Creates a QgsDataDefined from a decoded QgsStringMap.

Parameters

map	string map encoding of QgsDataDefined
baseName	base name for values in the string map

Returns: new QgsDataDefined if string map was successfully interpreted

See Also: toMap

Note: added in QGIS 2.9

Definition at line 48 of file qgsdatadefined.cpp.

bool QgsDataDefined::hasDefaultValues ( ) const

Returns whether the data defined container is set to all the default values, ie, disabled, with empty expression and no assigned field.

Returns: true if data defined container is set to default values

Note: added in QGIS 2.7

Definition at line 87 of file qgsdatadefined.cpp.

void QgsDataDefined::insertExpressionParam	(	QString	key,
		QVariant	param
	)

Definition at line 270 of file qgsdatadefined.cpp.

bool QgsDataDefined::isActive ( ) const

Definition at line 92 of file qgsdatadefined.cpp.

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

Definition at line 323 of file qgsdatadefined.cpp.

QgsDataDefined & QgsDataDefined::operator= ( QgsDataDefined const & rhs )

Assignment operator.

Note that after assignment the data defined object's expression will not be prepared.

Definition at line 328 of file qgsdatadefined.cpp.

bool QgsDataDefined::operator== ( const QgsDataDefined & other ) const

Definition at line 318 of file qgsdatadefined.cpp.

bool QgsDataDefined::prepareExpression ( QgsVectorLayer * layer )

Prepares the expression using a vector layer.

Parameters

layer vector layer

Returns: true if expression was successfully prepared

Definition at line 149 of file qgsdatadefined.cpp.

bool QgsDataDefined::prepareExpression ( const QgsFields & fields = QgsFields() )

Prepares the expression using a fields collection.

Parameters

fields

Returns: true if expression was successfully prepared

Note: added in QGIS 2.9

Definition at line 163 of file qgsdatadefined.cpp.

QStringList QgsDataDefined::referencedColumns ( QgsVectorLayer * layer )

Returns the columns referenced by the QgsDataDefined.

Parameters

layer vector layer, used for preparing the expression if required

Definition at line 220 of file qgsdatadefined.cpp.

QStringList QgsDataDefined::referencedColumns ( const QgsFields & fields = QgsFields() )

Returns the columns referenced by the QgsDataDefined.

Parameters

fields vector layer, used for preparing the expression if required

Note: added in QGIS 2.9

Definition at line 232 of file qgsdatadefined.cpp.

void QgsDataDefined::setActive ( bool active )

Definition at line 97 of file qgsdatadefined.cpp.

void QgsDataDefined::setExpressionParams ( QMap< QString, QVariant > params )

Definition at line 143 of file qgsdatadefined.cpp.

void QgsDataDefined::setExpressionString ( const QString & expr )

Definition at line 126 of file qgsdatadefined.cpp.

void QgsDataDefined::setField ( const QString & field )

Definition at line 260 of file qgsdatadefined.cpp.

bool QgsDataDefined::setFromXmlElement ( const QDomElement & element )

Sets the properties of the data defined container from an XML element.

Calling this will overwrite all the current properties of the container.

Parameters

element DOM element

Returns: true if properties were successfully read from element

Note: added in QGIS 2.7

See Also: toXmlElement

Definition at line 303 of file qgsdatadefined.cpp.

void QgsDataDefined::setUseExpression ( bool use )

Definition at line 111 of file qgsdatadefined.cpp.

QgsStringMap QgsDataDefined::toMap ( const QString & baseName = QString() ) const

Encodes the QgsDataDefined into a string map.

Parameters

baseName optional base name for values in the string map. Can be used to differentiate multiple QgsDataDefineds encoded in the same string map.

See Also: fromMap

Definition at line 276 of file qgsdatadefined.cpp.

QDomElement QgsDataDefined::toXmlElement	(	QDomDocument &	document,
		const QString &	elementName
	)		const

Returns a DOM element containing the properties of the data defined container.

Parameters

document	DOM document
elementName	name for DOM element

Returns: DOM element corresponding to data defined container

Note: added in QGIS 2.7

See Also: setFromXmlElement

Definition at line 293 of file qgsdatadefined.cpp.

bool QgsDataDefined::useExpression ( ) const

Definition at line 106 of file qgsdatadefined.cpp.

The documentation for this class was generated from the following files:

/tmp/buildd/qgis-2.10.1+git20150822+dd4475c+20trusty/src/core/qgsdatadefined.h
/tmp/buildd/qgis-2.10.1+git20150822+dd4475c+20trusty/src/core/qgsdatadefined.cpp

Public Member Functions

Static Public Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation