QGIS API Documentation  2.99.0-Master (f1c3692)
Signals | Public Member Functions | Static Public Member Functions | List of all members
QgsVectorLayerJoinBuffer Class Reference

Manages joined fields for a vector layer. More...

#include <qgsvectorlayerjoinbuffer.h>

Inheritance diagram for QgsVectorLayerJoinBuffer:
Inheritance graph
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Signals

void joinedFieldsChanged ()
 Emitted whenever the list of joined fields changes (e.g. More...
 

Public Member Functions

 QgsVectorLayerJoinBuffer (QgsVectorLayer *layer=nullptr)
 
bool addFeatures (QgsFeatureList &features, QgsFeatureSink::Flags flags=0) override
 Adds a list of features in joined layers. More...
 
bool addJoin (const QgsVectorLayerJoinInfo &joinInfo)
 Joins another vector layer to this layer. More...
 
bool changeAttributeValue (QgsFeatureId fid, int field, const QVariant &newValue, const QVariant &oldValue=QVariant())
 Changes attribute value in joined layers. More...
 
QgsVectorLayerJoinBufferclone () const
 Create a copy of the join buffer. More...
 
bool containsJoins () const
 Quick way to test if there is any join at all. More...
 
void createJoinCaches ()
 Calls cacheJoinLayer() for all vector joins. More...
 
bool deleteFeature (QgsFeatureId fid) const
 Deletes a feature from joined layers. More...
 
bool deleteFeatures (const QgsFeatureIds &fids) const
 Deletes a list of features from joined layers. More...
 
bool isAuxiliaryJoin (const QgsVectorLayerJoinInfo &info) const
 Returns true if the join information is about auxiliary layer, false otherwise. More...
 
QgsFeature joinedFeatureOf (const QgsVectorLayerJoinInfo *info, const QgsFeature &feature) const
 Returns the joined feature corresponding to the feature. More...
 
int joinedFieldsOffset (const QgsVectorLayerJoinInfo *info, const QgsFields &fields)
 Find out what is the first index of the join within fields. More...
 
const QgsVectorLayerJoinInfojoinForFieldIndex (int index, const QgsFields &fields, int &sourceFieldIndex) const
 Finds the vector join for a layer field index. More...
 
QList< const QgsVectorLayerJoinInfo * > joinsWhereFieldIsId (const QgsField &field) const
 Returns joins where the field of a target layer is considered as an id. More...
 
void readXml (const QDomNode &layer_node)
 Reads joins from project file. More...
 
bool removeJoin (const QString &joinLayerId)
 Removes a vector layer join. More...
 
void resolveReferences (QgsProject *project)
 Resolves layer IDs of joined layers using given project's available layers. More...
 
QgsFeature targetedFeatureOf (const QgsVectorLayerJoinInfo *info, const QgsFeature &feature) const
 Returns the targeted feature corresponding to the joined feature. More...
 
void updateFields (QgsFields &fields)
 Updates field map with joined attributes. More...
 
const QgsVectorJoinListvectorJoins () const
 
void writeXml (QDomNode &layer_node, QDomDocument &document) const
 Saves mVectorJoins to xml under the layer node. More...
 
- Public Member Functions inherited from QgsFeatureSink
virtual ~QgsFeatureSink ()=default
 
virtual bool addFeature (QgsFeature &feature, QgsFeatureSink::Flags flags=0)
 Adds a single feature to the sink. More...
 
virtual bool addFeatures (QgsFeatureIterator &iterator, QgsFeatureSink::Flags flags=0)
 Adds all features from the specified iterator to the sink. More...
 
virtual bool flushBuffer ()
 Flushes any internal buffer which may exist in the sink, causing any buffered features to be added to the sink's destination. More...
 

Static Public Member Functions

static QVector< int > joinSubsetIndices (QgsVectorLayer *joinLayer, const QStringList &joinFieldsSubset)
 Return a vector of indices for use in join based on field names from the layer. More...
 

Additional Inherited Members

- Public Types inherited from QgsFeatureSink
enum  Flag { FastInsert = 1 << 1 }
 Flags controlling how features are added to a sink. More...
 

Detailed Description

Manages joined fields for a vector layer.

Definition at line 35 of file qgsvectorlayerjoinbuffer.h.

Constructor & Destructor Documentation

◆ QgsVectorLayerJoinBuffer()

QgsVectorLayerJoinBuffer::QgsVectorLayerJoinBuffer ( QgsVectorLayer layer = nullptr)

Definition at line 28 of file qgsvectorlayerjoinbuffer.cpp.

Member Function Documentation

◆ addFeatures()

bool QgsVectorLayerJoinBuffer::addFeatures ( QgsFeatureList features,
QgsFeatureSink::Flags  flags = 0 
)
overridevirtual

Adds a list of features in joined layers.

Features given in parameter are those added in target layer. If a corresponding joined feature yet exists in a joined layer, then this feature is just updated. Note that if a corresponding joined feature has only empty fields, then it's not created nor added.

Parameters
featuresThe list of features added in the target layer
flagsUnused parameter
Returns
false if an error happened, true otherwise
Since
QGIS 3.0

Implements QgsFeatureSink.

Definition at line 527 of file qgsvectorlayerjoinbuffer.cpp.

◆ addJoin()

bool QgsVectorLayerJoinBuffer::addJoin ( const QgsVectorLayerJoinInfo joinInfo)

Joins another vector layer to this layer.

Parameters
joinInfojoin object containing join layer id, target and source field
Returns
(since 2.6) whether the join was successfully added

Definition at line 62 of file qgsvectorlayerjoinbuffer.cpp.

◆ changeAttributeValue()

bool QgsVectorLayerJoinBuffer::changeAttributeValue ( QgsFeatureId  fid,
int  field,
const QVariant &  newValue,
const QVariant &  oldValue = QVariant() 
)

Changes attribute value in joined layers.

The feature id given in parameter is the one added in target layer. If the corresponding joined feature does not exist in a joined layer, then it's automatically created if its fields are not empty.

Parameters
fidThe feature id
fieldThe field to update
newValueThe new value of the attribute
oldValueThe old value of the attribute
Returns
false if an error happened, true otherwise
Since
QGIS 3.0

Definition at line 612 of file qgsvectorlayerjoinbuffer.cpp.

◆ clone()

QgsVectorLayerJoinBuffer * QgsVectorLayerJoinBuffer::clone ( ) const

Create a copy of the join buffer.

Since
QGIS 2.6

Definition at line 469 of file qgsvectorlayerjoinbuffer.cpp.

◆ containsJoins()

bool QgsVectorLayerJoinBuffer::containsJoins ( ) const
inline

Quick way to test if there is any join at all.

Definition at line 77 of file qgsvectorlayerjoinbuffer.h.

◆ createJoinCaches()

void QgsVectorLayerJoinBuffer::createJoinCaches ( )

Calls cacheJoinLayer() for all vector joins.

Definition at line 252 of file qgsvectorlayerjoinbuffer.cpp.

◆ deleteFeature()

bool QgsVectorLayerJoinBuffer::deleteFeature ( QgsFeatureId  fid) const

Deletes a feature from joined layers.

The feature id given in parameter is the one coming from the target layer.

Parameters
fidThe feature id from the target layer to delete
Returns
false if an error happened, true otherwise
Since
QGIS 3.0

Definition at line 640 of file qgsvectorlayerjoinbuffer.cpp.

◆ deleteFeatures()

bool QgsVectorLayerJoinBuffer::deleteFeatures ( const QgsFeatureIds fids) const

Deletes a list of features from joined layers.

Feature ids given in aprameter are those coming from the target layer.

Parameters
fidsFeature ids from the target layer to delete
Returns
false if an error happened, true otherwise
Since
QGIS 3.0

Definition at line 645 of file qgsvectorlayerjoinbuffer.cpp.

◆ isAuxiliaryJoin()

bool QgsVectorLayerJoinBuffer::isAuxiliaryJoin ( const QgsVectorLayerJoinInfo info) const

Returns true if the join information is about auxiliary layer, false otherwise.

Parameters
infoThe join information
Returns
true if the join information is about auxiliary layer, false otherwise
Since
QGIS 3.0

Definition at line 666 of file qgsvectorlayerjoinbuffer.cpp.

◆ joinedFeatureOf()

QgsFeature QgsVectorLayerJoinBuffer::joinedFeatureOf ( const QgsVectorLayerJoinInfo info,
const QgsFeature feature 
) const

Returns the joined feature corresponding to the feature.

Parameters
infothe vector join information
featurethe feature of the target layer
Since
QGIS 3.0

Definition at line 425 of file qgsvectorlayerjoinbuffer.cpp.

◆ joinedFieldsChanged

void QgsVectorLayerJoinBuffer::joinedFieldsChanged ( )
signal

Emitted whenever the list of joined fields changes (e.g.

added join or joined layer's fields change)

Since
QGIS 2.6

◆ joinedFieldsOffset()

int QgsVectorLayerJoinBuffer::joinedFieldsOffset ( const QgsVectorLayerJoinInfo info,
const QgsFields fields 
)

Find out what is the first index of the join within fields.

Returns -1 if join is not present

Since
QGIS 2.6

Definition at line 374 of file qgsvectorlayerjoinbuffer.cpp.

◆ joinForFieldIndex()

const QgsVectorLayerJoinInfo * QgsVectorLayerJoinBuffer::joinForFieldIndex ( int  index,
const QgsFields fields,
int &  sourceFieldIndex 
) const

Finds the vector join for a layer field index.

Parameters
indexthis layers attribute index
fieldsfields of the vector layer (including joined fields)
sourceFieldIndexOutput: field's index in source layer

Definition at line 394 of file qgsvectorlayerjoinbuffer.cpp.

◆ joinSubsetIndices()

QVector< int > QgsVectorLayerJoinBuffer::joinSubsetIndices ( QgsVectorLayer joinLayer,
const QStringList &  joinFieldsSubset 
)
static

Return a vector of indices for use in join based on field names from the layer.

Since
QGIS 2.6

Definition at line 181 of file qgsvectorlayerjoinbuffer.cpp.

◆ joinsWhereFieldIsId()

QList< const QgsVectorLayerJoinInfo * > QgsVectorLayerJoinBuffer::joinsWhereFieldIsId ( const QgsField field) const

Returns joins where the field of a target layer is considered as an id.

Parameters
fieldthe field of a target layer
Returns
a list of vector joins
Since
QGIS 3.0

Definition at line 409 of file qgsvectorlayerjoinbuffer.cpp.

◆ readXml()

void QgsVectorLayerJoinBuffer::readXml ( const QDomNode &  layer_node)

Reads joins from project file.

Does not resolve layer IDs to layers - call resolveReferences() afterwards

Definition at line 312 of file qgsvectorlayerjoinbuffer.cpp.

◆ removeJoin()

bool QgsVectorLayerJoinBuffer::removeJoin ( const QString &  joinLayerId)

Removes a vector layer join.

Returns
true if join was found and successfully removed

Definition at line 99 of file qgsvectorlayerjoinbuffer.cpp.

◆ resolveReferences()

void QgsVectorLayerJoinBuffer::resolveReferences ( QgsProject project)

Resolves layer IDs of joined layers using given project's available layers.

Since
QGIS 3.0

Definition at line 354 of file qgsvectorlayerjoinbuffer.cpp.

◆ targetedFeatureOf()

QgsFeature QgsVectorLayerJoinBuffer::targetedFeatureOf ( const QgsVectorLayerJoinInfo info,
const QgsFeature feature 
) const

Returns the targeted feature corresponding to the joined feature.

Parameters
infothe vector join information
featurethe feature of the joined layer
Since
QGIS 3.0

Definition at line 449 of file qgsvectorlayerjoinbuffer.cpp.

◆ updateFields()

void QgsVectorLayerJoinBuffer::updateFields ( QgsFields fields)

Updates field map with joined attributes.

Parameters
fieldsmap to append joined attributes

Definition at line 202 of file qgsvectorlayerjoinbuffer.cpp.

◆ vectorJoins()

const QgsVectorJoinList& QgsVectorLayerJoinBuffer::vectorJoins ( ) const
inline

Definition at line 79 of file qgsvectorlayerjoinbuffer.h.

◆ writeXml()

void QgsVectorLayerJoinBuffer::writeXml ( QDomNode &  layer_node,
QDomDocument &  document 
) const

Saves mVectorJoins to xml under the layer node.

Definition at line 264 of file qgsvectorlayerjoinbuffer.cpp.


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