QGIS API Documentation  3.17.0-Master (a035f434f4)
qgsalgorithmaggregate.h
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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
Class for parsing and evaluation of expressions (formerly called "search strings").
virtual bool prepareAlgorithm(const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback) SIP_THROW(QgsProcessingException)
Prepares the algorithm to run using the specified parameters.
Base class for all map layer types.
Definition: qgsmaplayer.h:83
Base class for providing feedback from a processing algorithm.
virtual QString name() const =0
Returns the algorithm name, used for identifying the algorithm.
virtual QString group() const
Returns the name of the group this algorithm belongs to.
An interface for objects which accept features via addFeature(s) methods.
Container of fields for a vector layer.
Definition: qgsfields.h:44
virtual QStringList tags() const
Returns a list of tags which relate to the algorithm, and are used to assist users in searching for s...
The feature class encapsulates a single feature including its id, geometry and a list of field/values...
Definition: qgsfeature.h:55
virtual QString shortHelpString() const
Returns a localised short helper string for the algorithm.
Abstract base class for processing algorithms.
virtual void initAlgorithm(const QVariantMap &configuration=QVariantMap())=0
Initializes the algorithm using the specified configuration.
virtual bool supportInPlaceEdit(const QgsMapLayer *layer) const
Checks whether this algorithm supports in-place editing on the given layer Default implementation ret...
#define SIP_FACTORY
Definition: qgis_sip.h:76
virtual QgsProcessingAlgorithm * createInstance() const =0
Creates a new instance of the algorithm class.
A general purpose distance and area calculator, capable of performing ellipsoid based calculations...
virtual QVariantMap processAlgorithm(const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback) SIP_THROW(QgsProcessingException)=0
Runs the algorithm using the specified parameters.
virtual QString displayName() const =0
Returns the translated algorithm name, which should be used for any user-visible display of the algor...
virtual QString groupId() const
Returns the unique ID of the group this algorithm belongs to.
Contains information about the context in which a processing algorithm is executed.