AVList and AVKey: Attribute-Value Configuration System

public interface AVList {

    // ---- Core key/value operations ----

    // Store a value; returns the previous value (or null)
    Object setValue(String key, Object value);

    // Bulk copy from another AVList
    AVList setValues(AVList avList);

    // Retrieve a value by key (returns null if absent)
    Object getValue(String key);

    // Type-checked String retrieval (throws WWRuntimeException if not a String)
    String getStringValue(String key);

    // All values in the collection
    Collection<Object> getValues();

    // All key/value pairs as a Set
    Set<Map.Entry<String, Object>> getEntries();

    // Membership test
    boolean hasKey(String key);

    // Remove a key; returns previous value
    Object removeKey(String key);

    // Shallow copy of the entire list
    AVList copy();

    // Clear all entries
    AVList clearList();

    // ---- Property change listeners ----

    // Listen for changes to a specific key
    void addPropertyChangeListener(String propertyName,
        java.beans.PropertyChangeListener listener);
    void removePropertyChangeListener(String propertyName,
        java.beans.PropertyChangeListener listener);

    // Listen for all changes
    void addPropertyChangeListener(java.beans.PropertyChangeListener listener);
    void removePropertyChangeListener(java.beans.PropertyChangeListener listener);

    // Fire a change event for a key
    void firePropertyChange(String propertyName, Object oldValue, Object newValue);
    void firePropertyChange(java.beans.PropertyChangeEvent propertyChangeEvent);
}

AVList params = new AVListImpl();

params.setValue(AVKey.DATASET_NAME,    "Blue Marble");
params.setValue(AVKey.FORMAT_SUFFIX,   ".dds");
params.setValue(AVKey.NUM_LEVELS,      14);
params.setValue(AVKey.TILE_WIDTH,      512);
params.setValue(AVKey.TILE_HEIGHT,     512);

// Read back values
String name    = (String)  params.getValue(AVKey.DATASET_NAME);
Integer levels = (Integer) params.getValue(AVKey.NUM_LEVELS);

// Null-safe typed retrieval
String display = params.getStringValue(AVKey.DISPLAY_NAME);  // null if absent

// Check and remove
if (params.hasKey(AVKey.FORMAT_SUFFIX)) {
    params.removeKey(AVKey.FORMAT_SUFFIX);
}

// Shallow copy
AVList copy = params.copy();

public class WWObjectImpl extends AVListImpl implements WWObject {

    // Fires a named property change to all registered listeners
    // who listen for propertyName or all-property listeners
    @Override
    public void firePropertyChange(String propertyName,
                                   Object oldValue,
                                   Object newValue) {
        super.firePropertyChange(propertyName, oldValue, newValue);
    }
}

Layer layer = new RenderableLayer();

layer.addPropertyChangeListener(AVKey.DISPLAY_NAME, event -> {
    System.out.println("Name changed: " + event.getNewValue());
});

// Trigger the listener
layer.setName("Updated Name");
// → "Name changed: Updated Name"

import gov.nasa.worldwind.avlist.*;
import gov.nasa.worldwind.geom.*;

// Create parameter list for a custom TiledImageLayer subclass
AVList params = new AVListImpl();

// Service endpoint
params.setValue(AVKey.SERVICE,
    "https://tiles.example.com/imagery");
params.setValue(AVKey.SERVICE_NAME,  "OGC:WMS");
params.setValue(AVKey.LAYER_NAMES,   "base_imagery");
params.setValue(AVKey.IMAGE_FORMAT,  "image/png");

// Tile pyramid structure
params.setValue(AVKey.DATASET_NAME,    "ExampleImagery");
params.setValue(AVKey.DATA_CACHE_NAME, "Earth/ExampleImagery");
params.setValue(AVKey.FORMAT_SUFFIX,   ".dds");
params.setValue(AVKey.NUM_LEVELS,      14);
params.setValue(AVKey.NUM_EMPTY_LEVELS, 0);
params.setValue(AVKey.TILE_WIDTH,      512);
params.setValue(AVKey.TILE_HEIGHT,     512);
params.setValue(AVKey.LEVEL_ZERO_TILE_DELTA,
    new LatLon(Angle.fromDegrees(36d), Angle.fromDegrees(36d)));
params.setValue(AVKey.SECTOR, Sector.FULL_SPHERE);

// Data properties
params.setValue(AVKey.DISPLAY_NAME,  "Example Imagery");
params.setValue(AVKey.DESCRIPTION,   "High-resolution base imagery layer");

// Listen for changes (e.g., to re-initialize on config reload)
params.addPropertyChangeListener(AVKey.SERVICE, event -> {
    System.out.println("Service URL changed: " + event.getNewValue());
});

// Pass to a layer constructor
WMSTiledImageLayer layer = new WMSTiledImageLayer(params);
wwd.getModel().getLayers().add(layer);