QGIS API Documentation  2.15.0-Master (1f0fce7)
Public Member Functions | Protected Attributes | List of all members
QgsExpression::NodeLiteral Class Reference

#include <qgsexpression.h>

Inheritance diagram for QgsExpression::NodeLiteral:
Inheritance graph
[legend]

Public Member Functions

 NodeLiteral (const QVariant &value)
 
virtual void accept (Visitor &v) const override
 Support the visitor pattern. More...
 
virtual Nodeclone () const override
 Generate a clone of this node. More...
 
virtual QString dump () const override
 Abstract virtual dump method. More...
 
virtual QVariant eval (QgsExpression *parent, const QgsExpressionContext *context) override
 Abstract virtual eval method Errors are reported to the parent. More...
 
virtual bool needsGeometry () const override
 Abstract virtual method which returns if the geometry is required to evaluate this expression. More...
 
virtual NodeType nodeType () const override
 Abstract virtual that returns the type of this node. More...
 
virtual bool prepare (QgsExpression *parent, const QgsExpressionContext *context) override
 Abstract virtual preparation method Errors are reported to the parent. More...
 
virtual QStringList referencedColumns () const override
 Abstract virtual method which returns a list of columns required to evaluate this node. More...
 
QVariant value () const
 The value of the literal. More...
 
- Public Member Functions inherited from QgsExpression::Node
virtual ~Node ()
 
virtual Q_DECL_DEPRECATED QVariant eval (QgsExpression *parent, const QgsFeature *f)
 Abstract virtual eval method Errors are reported to the parent. More...
 
virtual Q_DECL_DEPRECATED bool prepare (QgsExpression *parent, const QgsFields &fields)
 Abstract virtual preparation method Errors are reported to the parent. More...
 

Protected Attributes

QVariant mValue
 

Detailed Description

Definition at line 1204 of file qgsexpression.h.

Constructor & Destructor Documentation

QgsExpression::NodeLiteral::NodeLiteral ( const QVariant value)
inline

Definition at line 1207 of file qgsexpression.h.

Member Function Documentation

virtual void QgsExpression::NodeLiteral::accept ( Visitor v) const
inlineoverridevirtual

Support the visitor pattern.

For any implementation this should look like

C++:

v.visit( *this );

Python:

v.visit( self)
Parameters
vA visitor that visits this node.

Implements QgsExpression::Node.

Definition at line 1221 of file qgsexpression.h.

QgsExpression::Node * QgsExpression::NodeLiteral::clone ( ) const
overridevirtual

Generate a clone of this node.

Make sure that the clone does not contain any information which is generated in prepare and context related. Ownership is transferred to the caller.

Returns
a deep copy of this node.

Implements QgsExpression::Node.

Definition at line 4661 of file qgsexpression.cpp.

QString QgsExpression::NodeLiteral::dump ( ) const
overridevirtual

Abstract virtual dump method.

Returns
An expression which represents this node as string

Implements QgsExpression::Node.

Definition at line 4641 of file qgsexpression.cpp.

QVariant QgsExpression::NodeLiteral::eval ( QgsExpression parent,
const QgsExpressionContext context 
)
overridevirtual

Abstract virtual eval method Errors are reported to the parent.

Note
added in QGIS 2.12

Reimplemented from QgsExpression::Node.

Definition at line 4626 of file qgsexpression.cpp.

virtual bool QgsExpression::NodeLiteral::needsGeometry ( ) const
inlineoverridevirtual

Abstract virtual method which returns if the geometry is required to evaluate this expression.

This needs to call needsGeometry() recursively on any child nodes.

Returns
true if a geometry is required to evaluate this expression

Implements QgsExpression::Node.

Definition at line 1220 of file qgsexpression.h.

virtual NodeType QgsExpression::NodeLiteral::nodeType ( ) const
inlineoverridevirtual

Abstract virtual that returns the type of this node.

Returns
The type of this node

Implements QgsExpression::Node.

Definition at line 1214 of file qgsexpression.h.

bool QgsExpression::NodeLiteral::prepare ( QgsExpression parent,
const QgsExpressionContext context 
)
overridevirtual

Abstract virtual preparation method Errors are reported to the parent.

Note
added in QGIS 2.12

Reimplemented from QgsExpression::Node.

Definition at line 4633 of file qgsexpression.cpp.

virtual QStringList QgsExpression::NodeLiteral::referencedColumns ( ) const
inlineoverridevirtual

Abstract virtual method which returns a list of columns required to evaluate this node.

When reimplementing this, you need to return any column that is required to evaluate this node and in addition recursively collect all the columns required to evaluate child nodes.

Returns
A list of columns required to evaluate this expression

Implements QgsExpression::Node.

Definition at line 1219 of file qgsexpression.h.

QVariant QgsExpression::NodeLiteral::value ( ) const
inline

The value of the literal.

Definition at line 1212 of file qgsexpression.h.

Member Data Documentation

QVariant QgsExpression::NodeLiteral::mValue
protected

Definition at line 1225 of file qgsexpression.h.


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