luciad::FeatureStateManager Class Reference

Manages feature states. More...

#include <luciad/layers/features/FeatureStateManager.h>

Classes
class	Change
	This class is used to build feature state changes. More...

Public Member Functions
virtual	~FeatureStateManager ()=default
virtual void	addObserver (std::shared_ptr< IFeatureStateObserver > observer, bool seedObserver=false)=0
	Adds an observer that allows to inspect feature state changes. More...
virtual void	applyStateChange (const Change &featureStateChange)=0
	Applies the given state change. More...
virtual void	clearEnabledStates (const LayerFeatureId &layerFeatureId)=0
	Clears (i.e. More...
virtual bool	isStateEnabled (LayerFeatureId layerFeatureId, const FeatureState &featureState) const =0
	Checks if the given feature state is enabled for the given feature identifier. More...
virtual void	removeObserver (const std::shared_ptr< IFeatureStateObserver > &observer)=0
	Removes the given observer. More...

Detailed Description

Manages feature states.

In essence, it keeps a mapping of enabled/disabled states for each feature for specific FeatureState instances. This class can for example manage which features are selected.

Example

  // Create and add a selection observer that prints which feature is selected or deselected
  auto selectionObserver = IFeatureStateObserver::create([](const FeatureStateEvent& changeEvent) {
    for (auto changedFeature : changeEvent.getChangedFeatures(FeatureState::selected())) {
      bool selected = changeEvent.getChange(FeatureState::selected(), changedFeature);
      std::string selectedMessage = selected ? "Selected" : "Deselected";
      std::cout << "Feature " << changedFeature.featureId << " => " << selectedMessage << std::endl;
    }
  });
  featureStateManager->addObserver(selectionObserver);
 
  // Apply a state change.
  auto change = FeatureStateManager::Change::create();
  change->clearState(FeatureState::selected());
  change->setState(feature1, FeatureState::selected(), true);
  featureStateManager->applyStateChange(*change);
 
  // Assuming that feature 2 was already selected before, the output will be:
  // Feature 2 => Deselected
  // Feature 1 => Selected
  featureStateManager->removeObserver(selectionObserver);

Constructor & Destructor Documentation

~FeatureStateManager()

virtual luciad::FeatureStateManager::~FeatureStateManager ( )

virtualdefault

Member Function Documentation

addObserver()

virtual void luciad::FeatureStateManager::addObserver ( std::shared_ptr< IFeatureStateObserver >  observer, bool  seedObserver = false  )

pure virtual

Adds an observer that allows to inspect feature state changes.

Note: this method should only be called on the UI thread

Parameters

observer	an observer
seedObserver	whether to inform the observer about the features for which a FeatureState is currently enabled

Exceptions

InvalidArgumentException	if the observer is already added.
NullArgumentException	if observer is nullptr.

applyStateChange()

virtual void luciad::FeatureStateManager::applyStateChange ( const Change &  featureStateChange )

pure virtual

Applies the given state change.

After this call, the FeatureStateManager::isStateEnabled method will reflect the given changes, and the registered observers will have been notified of the concrete changes for each feature.

Note: this method should only be called on the UI thread

Parameters

featureStateChange

a feature state change

clearEnabledStates()

virtual void luciad::FeatureStateManager::clearEnabledStates ( const LayerFeatureId &  layerFeatureId )

pure virtual

Clears (i.e.

sets to false) all enabled stated for the given feature.

Note: this method should only be called on the UI thread

Parameters

layerFeatureId

the feature for which to clear all enabled states.

isStateEnabled()

virtual bool luciad::FeatureStateManager::isStateEnabled ( LayerFeatureId  layerFeatureId, const FeatureState &  featureState  ) const

pure virtual

Checks if the given feature state is enabled for the given feature identifier.

Note: this method can be called on any thread.

Parameters

layerFeatureId	a feature identifier
featureState	a feature state

Returns

if the given feature state is enabled for the given feature identifier.

removeObserver()

virtual void luciad::FeatureStateManager::removeObserver ( const std::shared_ptr< IFeatureStateObserver > &  observer )

pure virtual

Removes the given observer.

Note: this method should only be called on the UI thread

Parameters

observer

an observer

Exceptions

InvalidArgumentException	if the observer was not added.
NullArgumentException	if observer is nullptr.