com.luciad.layers.features

Class FeatureStateManager

java.lang.Object

com.luciad.layers.features.FeatureStateManager

All Implemented Interfaces:

AutoCloseable

public final class FeatureStateManager
extends Object
implements AutoCloseable

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
    IFeatureStateObserver selectionObserver = new IFeatureStateObserver() {
      @Override
      public void onFeatureStateChanged(FeatureStateEvent featureStateEvent) {
        for (LayerFeatureId changedFeature : featureStateEvent.getChangedFeatures(FeatureState.Selected)) {
          boolean selected = featureStateEvent.getChange(FeatureState.Selected, changedFeature);
          String selectedMessage = selected ? "Selected" : "Deselected";
          Log.i("feature-state", "Feature " + changedFeature.getFeatureId() + " => " + selectedMessage);
        }
      }
    };
    featureStateManager.addObserver(selectionObserver);

    // Apply a state change.
    FeatureStateManager.Change 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);

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	FeatureStateManager.Change This class is used to build feature state changes.

Method Summary

Modifier and Type	Method and Description
void	addObserver(IFeatureStateObserver observer) Adds an observer that allows to inspect feature state changes.
void	addObserver(IFeatureStateObserver observer, boolean seedObserver) Adds an observer that allows to inspect feature state changes.
void	applyStateChange(FeatureStateManager.Change featureStateChange) Applies the given state change.
void	clearEnabledStates(LayerFeatureId layerFeatureId) Clears (i.e.
void	close()
protected void	finalize()
boolean	isStateEnabled(LayerFeatureId layerFeatureId, FeatureState featureState) Checks if the given feature state is enabled for the given feature identifier.
void	removeObserver(IFeatureStateObserver observer) Removes the given observer.

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

finalize

protected void finalize()

Overrides:

finalize in class Object

close

public void close()

Specified by:

close in interface AutoCloseable

applyStateChange

public void applyStateChange(@NotNull
                             FeatureStateManager.Change featureStateChange)

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

public void clearEnabledStates(@NotNull
                               LayerFeatureId layerFeatureId)

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

public boolean isStateEnabled(@NotNull
                              LayerFeatureId layerFeatureId,
                              @NotNull
                              FeatureState featureState)

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.

addObserver

public void addObserver(@NotNull
                        IFeatureStateObserver observer,
                        boolean seedObserver)
                 throws IllegalArgumentException,
                        NullPointerException

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

Throws:

IllegalArgumentException - if the observer is already added.

NullPointerException - if observer is null.

addObserver

public void addObserver(@NotNull
                        IFeatureStateObserver observer)
                 throws IllegalArgumentException,
                        NullPointerException

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

Throws:

IllegalArgumentException - if the observer is already added.

NullPointerException - if observer is null.

removeObserver

public void removeObserver(@NotNull
                           IFeatureStateObserver observer)
                    throws IllegalArgumentException,
                           NullPointerException

Removes the given observer.

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

Parameters:

observer - an observer

Throws:

IllegalArgumentException - if the observer was not added.

NullPointerException - if observer is null.