QGIS API Documentation  3.11.0-Master (68611307d7)
Signals | Public Member Functions | Protected Member Functions | List of all members
QgsProcessingAlgRunnerTask Class Reference

QgsTask task which runs a QgsProcessingAlgorithm in a background task. More...

#include <qgsprocessingalgrunnertask.h>

Inheritance diagram for QgsProcessingAlgRunnerTask:
Inheritance graph
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Signals

void executed (bool successful, const QVariantMap &results)
 Emitted when the algorithm has finished execution. More...
 
- Signals inherited from QgsTask
void begun ()
 Will be emitted by task to indicate its commencement. More...
 
void progressChanged (double progress)
 Will be emitted by task when its progress changes. More...
 
void statusChanged (int status)
 Will be emitted by task when its status changes. More...
 
void taskCompleted ()
 Will be emitted by task to indicate its successful completion. More...
 
void taskTerminated ()
 Will be emitted by task if it has terminated for any reason other then completion (e.g., when a task has been canceled or encountered an internal error). More...
 

Public Member Functions

 QgsProcessingAlgRunnerTask (const QgsProcessingAlgorithm *algorithm, const QVariantMap &parameters, QgsProcessingContext &context, QgsProcessingFeedback *feedback=nullptr)
 Constructor for QgsProcessingAlgRunnerTask. More...
 
void cancel () override
 Notifies the task that it should terminate. More...
 
- Public Member Functions inherited from QgsTask
 QgsTask (const QString &description=QString(), QgsTask::Flags flags=AllFlags)
 Constructor for QgsTask. More...
 
 ~QgsTask () override
 
void addSubTask (QgsTask *subTask, const QgsTaskList &dependencies=QgsTaskList(), SubTaskDependency subTaskDependency=SubTaskIndependent)
 Adds a subtask to this task. More...
 
bool canCancel () const
 Returns true if the task can be canceled. More...
 
QList< QgsMapLayer *> dependentLayers () const
 Returns the list of layers on which the task depends. More...
 
QString description () const
 Returns the task's description. More...
 
qint64 elapsedTime () const
 Returns the elapsed time since the task commenced, in milliseconds. More...
 
Flags flags () const
 Returns the flags associated with the task. More...
 
void hold ()
 Places the task on hold. More...
 
bool isActive () const
 Returns true if the task is active, ie it is not complete and has not been canceled. More...
 
double progress () const
 Returns the task's progress (between 0.0 and 100.0) More...
 
void setDependentLayers (const QList< QgsMapLayer *> &dependentLayers)
 Sets a list of layers on which the task depends. More...
 
void setDescription (const QString &description)
 Sets the task's description. More...
 
TaskStatus status () const
 Returns the current task status. More...
 
void unhold ()
 Releases the task from being held. More...
 
bool waitForFinished (int timeout=30000)
 Blocks the current thread until the task finishes or a maximum of timeout milliseconds. More...
 

Protected Member Functions

void finished (bool result) override
 If the task is managed by a QgsTaskManager, this will be called after the task has finished (whether through successful completion or via early termination). More...
 
bool run () override
 Performs the task's operation. More...
 
- Protected Member Functions inherited from QgsTask
bool isCanceled () const
 Will return true if task should terminate ASAP. More...
 

Additional Inherited Members

- Public Types inherited from QgsTask
enum  Flag { CanCancel = 1 << 1, AllFlags = CanCancel }
 Task flags. More...
 
enum  SubTaskDependency { SubTaskIndependent = 0, ParentDependsOnSubTask }
 Controls how subtasks relate to their parent task. More...
 
enum  TaskStatus {
  Queued, OnHold, Running, Complete,
  Terminated
}
 Status of tasks. More...
 
- Protected Slots inherited from QgsTask
void setProgress (double progress)
 Sets the task's current progress. More...
 

Detailed Description

QgsTask task which runs a QgsProcessingAlgorithm in a background task.

Since
QGIS 3.0

Definition at line 35 of file qgsprocessingalgrunnertask.h.

Constructor & Destructor Documentation

◆ QgsProcessingAlgRunnerTask()

QgsProcessingAlgRunnerTask::QgsProcessingAlgRunnerTask ( const QgsProcessingAlgorithm algorithm,
const QVariantMap &  parameters,
QgsProcessingContext context,
QgsProcessingFeedback feedback = nullptr 
)

Constructor for QgsProcessingAlgRunnerTask.

Takes an algorithm, algorithm parameters and processing context.

Definition at line 25 of file qgsprocessingalgrunnertask.cpp.

Member Function Documentation

◆ cancel()

void QgsProcessingAlgRunnerTask::cancel ( )
overridevirtual

Notifies the task that it should terminate.

Calling this is not guaranteed to immediately end the task, rather it sets the isCanceled() flag which task subclasses can check and terminate their operations at an appropriate time. Any subtasks owned by this task will also be canceled. Derived classes must ensure that the base class implementation is called from any overridden version.

See also
isCanceled()

Reimplemented from QgsTask.

Definition at line 50 of file qgsprocessingalgrunnertask.cpp.

◆ executed

void QgsProcessingAlgRunnerTask::executed ( bool  successful,
const QVariantMap &  results 
)
signal

Emitted when the algorithm has finished execution.

If the algorithm completed execution without errors then successful will be true. The results argument contains the results reported by the algorithm.

◆ finished()

void QgsProcessingAlgRunnerTask::finished ( bool  result)
overrideprotectedvirtual

If the task is managed by a QgsTaskManager, this will be called after the task has finished (whether through successful completion or via early termination).

The result argument reflects whether the task was successfully completed or not. This method is always called from the main thread, so it is safe to create widgets and perform other operations which require the main thread. However, the GUI will be blocked for the duration of this method so tasks should avoid performing any lengthy operations here.

Reimplemented from QgsTask.

Definition at line 78 of file qgsprocessingalgrunnertask.cpp.

◆ run()

bool QgsProcessingAlgRunnerTask::run ( )
overrideprotectedvirtual

Performs the task's operation.

This method will be called when the task commences (ie via calling start() ), and subclasses should implement the operation they wish to perform in the background within this method.

A task must return a boolean value to indicate whether the task was completed successfully or terminated before completion.

Implements QgsTask.

Definition at line 57 of file qgsprocessingalgrunnertask.cpp.


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