This class can be used to save changes to an IFeatureModel's backend. More...

#include <luciad/models/features/FeatureModelPersistenceManager.h>

Classes
class	Builder
	`IFeatureModel` implementations that have support for `saving changes` can use this class to create a FeatureModelPersistenceManager instance. More...

Public Member Functions
void	discardChanges ()
	Discards the unsaved (in-memory) changes of the `IFeatureModel`, restoring the `IFeatureModel's` state back to that of its backend. More...

std::vector< FeatureChange >	getChanges () const
	Retrieves a list of all unsaved (in-memory) changes to the `IFeatureModel`. More...

std::optional< FeatureSaveErrorInfo >	saveChanges ()
	Save the `in-memory changes` in the IFeatureModel's backend (for example a file or database). More...

Static Public Member Functions
static Builder	newBuilder ()
	Returns a new FeatureModelPersistenceManager builder. More...

Detailed Description

This class can be used to save changes to an IFeatureModel's backend.

The main goal of this class it to give more control over when changes are persisted. An important difference between the updater and the FeatureModelPersistenceManager is the frequency at which they are used, with the FeatureModelPersistenceManager typically being used less often. In other words:

The updater typically only makes in-memory changes. These can occur in a high frequency and can be executed fast.
FeatureModelPersistenceManager can persist these in-memory changes. This is slower to execute, can require more resources (disk access for example), but can be performed at a lower frequency.

For example: when dragging a point from one location to another in an editor configured to update on any change, many small updates are done along the way. In contrast, a save typically only happens when the editing is finished.

A FeatureModelPersistenceManager can be accessed through the model using IFeatureModel::getPersistenceManager.

See this article for more information.

Since: 2023.1

Member Function Documentation

◆ discardChanges()

void luciad::FeatureModelPersistenceManager::discardChanges ( )

Discards the unsaved (in-memory) changes of the IFeatureModel, restoring the IFeatureModel's state back to that of its backend.

All observers will be notified with a FeatureModelEvent containing the FeatureChanges necessary to go back to the backend's state.

◆ getChanges()

std::vector< FeatureChange > luciad::FeatureModelPersistenceManager::getChanges ( ) const

Retrieves a list of all unsaved (in-memory) changes to the IFeatureModel.

That is, the changes that need to be saved to the IFeatureModel's backend to persist all in-memory changes. Multiple updates to the same feature will be condensed to a single FeatureChange.

Returns: list of all unsaved changes to the IFeatureModel

◆ newBuilder()

static Builder luciad::FeatureModelPersistenceManager::newBuilder ( )

static

Returns a new FeatureModelPersistenceManager builder.

Returns: a new FeatureModelPersistenceManager builder.

◆ saveChanges()

std::optional< FeatureSaveErrorInfo > luciad::FeatureModelPersistenceManager::saveChanges ( )

Save the in-memory changes in the IFeatureModel's backend (for example a file or database).

Typically, calling this method shouldn't modify the in-memory state of the model. So the feature model will not send out events through its observers. In some cases however (depending on the model implementation), feature changes can occur while changes are saved. In that case, the model's observers need to be notified of those changes.

Returns: std::nullopt on success, or error information on failure.

Classes