QGIS API Documentation  3.16.0-Hannover (43b64b13f3)
qgsalgorithmaggregate.h
Go to the documentation of this file.
1 /***************************************************************************
2  qgsalgorithmaggregate.h
3  ---------------------------------
4  begin : June 2020
5  copyright : (C) 2020 by Nyall Dawson
6  email : nyall dot dawson at gmail dot com
7  ***************************************************************************/
8 
9 /***************************************************************************
10  * *
11  * This program is free software; you can redistribute it and/or modify *
12  * it under the terms of the GNU General Public License as published by *
13  * the Free Software Foundation; either version 2 of the License, or *
14  * (at your option) any later version. *
15  * *
16  ***************************************************************************/
17 
18 #ifndef QGSALGORITHMAGGREGATE_H
19 #define QGSALGORITHMAGGREGATE_H
20 
21 #define SIP_NO_FILE
22 
23 #include "qgis_sip.h"
24 #include "qgsprocessingalgorithm.h"
25 
27 
31 class QgsAggregateAlgorithm : public QgsProcessingAlgorithm
32 {
33 
34  public:
35 
36  QgsAggregateAlgorithm() = default;
37  QString name() const override;
38  QString displayName() const override;
39  QStringList tags() const override;
40  QString group() const override;
41  QString groupId() const override;
42  QString shortHelpString() const override;
43  QgsAggregateAlgorithm *createInstance() const override SIP_FACTORY;
44  void initAlgorithm( const QVariantMap &configuration = QVariantMap() ) override;
45 
46  protected:
47 
48  bool prepareAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback ) override;
49  QVariantMap processAlgorithm( const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback ) override;
50 
51  bool supportInPlaceEdit( const QgsMapLayer *layer ) const override;
52 
53  private:
54 
55  QgsExpression createExpression( const QString &expressionString, QgsProcessingContext &context ) const;
56 
57  std::unique_ptr< QgsProcessingFeatureSource > mSource;
58  QString mGroupBy;
59 
60  QgsExpression mGroupByExpression;
61  QgsExpression mGeometryExpression;
62 
63  QgsFields mFields;
64  QList< QgsExpression > mExpressions;
65  QgsDistanceArea mDa;
66 
67  struct Group
68  {
69  QgsFeatureSink *sink = nullptr;
70  QgsMapLayer *layer = nullptr;
71  QgsFeature feature;
72  };
73 
74 };
75 
77 
78 #endif // QGSALGORITHMAGGREGATE_H
QgsProcessingAlgorithm::displayName
virtual QString displayName() const =0
Returns the translated algorithm name, which should be used for any user-visible display of the algor...
QgsProcessingFeedback
Base class for providing feedback from a processing algorithm.
Definition: qgsprocessingfeedback.h:38
QgsFields
Container of fields for a vector layer.
Definition: qgsfields.h:45
QgsProcessingAlgorithm::groupId
virtual QString groupId() const
Returns the unique ID of the group this algorithm belongs to.
Definition: qgsprocessingalgorithm.h:233
QgsProcessingAlgorithm::createInstance
virtual QgsProcessingAlgorithm * createInstance() const =0
Creates a new instance of the algorithm class.
QgsProcessingAlgorithm::prepareAlgorithm
virtual bool prepareAlgorithm(const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback) SIP_THROW(QgsProcessingException)
Prepares the algorithm to run using the specified parameters.
Definition: qgsprocessingalgorithm.cpp:373
SIP_FACTORY
#define SIP_FACTORY
Definition: qgis_sip.h:76
QgsProcessingAlgorithm::name
virtual QString name() const =0
Returns the algorithm name, used for identifying the algorithm.
QgsProcessingAlgorithm::processAlgorithm
virtual QVariantMap processAlgorithm(const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback) SIP_THROW(QgsProcessingException)=0
Runs the algorithm using the specified parameters.
QgsProcessingContext
Contains information about the context in which a processing algorithm is executed.
Definition: qgsprocessingcontext.h:44
qgsprocessingalgorithm.h
qgis_sip.h
QgsProcessingAlgorithm::shortHelpString
virtual QString shortHelpString() const
Returns a localised short helper string for the algorithm.
Definition: qgsprocessingalgorithm.cpp:63
QgsProcessingAlgorithm::supportInPlaceEdit
virtual bool supportInPlaceEdit(const QgsMapLayer *layer) const
Checks whether this algorithm supports in-place editing on the given layer Default implementation ret...
Definition: qgsprocessingalgorithm.cpp:869
QgsProcessingAlgorithm
Abstract base class for processing algorithms.
Definition: qgsprocessingalgorithm.h:52
QgsMapLayer
Base class for all map layer types.
Definition: qgsmaplayer.h:83
QgsDistanceArea
A general purpose distance and area calculator, capable of performing ellipsoid based calculations.
Definition: qgsdistancearea.h:50
QgsProcessingAlgorithm::group
virtual QString group() const
Returns the name of the group this algorithm belongs to.
Definition: qgsprocessingalgorithm.h:224
QgsFeature
The feature class encapsulates a single feature including its id, geometry and a list of field/values...
Definition: qgsfeature.h:56
QgsExpression
Class for parsing and evaluation of expressions (formerly called "search strings").
Definition: qgsexpression.h:105
QgsFeatureSink
An interface for objects which accept features via addFeature(s) methods.
Definition: qgsfeaturesink.h:34
QgsProcessingAlgorithm::tags
virtual QStringList tags() const
Returns a list of tags which relate to the algorithm, and are used to assist users in searching for s...
Definition: qgsprocessingalgorithm.h:180
QgsProcessingAlgorithm::initAlgorithm
virtual void initAlgorithm(const QVariantMap &configuration=QVariantMap())=0
Initializes the algorithm using the specified configuration.