tweak

planetiler-core/src/main/java/com/onthegomap/planetiler/VectorTile.java

@@ -81,7 +81,7 @@ public class VectorTile {
   private static final int EXTENT = 4096;
   private static final double SIZE = 256d;
   private final Map<String, Layer> layers = new LinkedHashMap<>();
-  private LayerAttrStats.Updater.ForZoom layerStatsTracker = LayerAttrStats.Updater.ForZoom.NO_OP;
+  private LayerAttrStats.Updater.ForZoom layerStatsTracker = LayerAttrStats.Updater.ForZoom.NOOP;
 
   private static int[] getCommands(Geometry input, int scale) {
     var encoder = new CommandEncoder(scale);
@@ -599,6 +599,11 @@ public class VectorTile {
     return layers.values().stream().allMatch(v -> v.encodedFeatures.isEmpty()) || containsOnlyFillsOrEdges();
   }
 
+  /**
+   * Call back to {@code layerStats} as vector tile features are being encoded in
+   * {@link #addLayerFeatures(String, List)} to track attribute types present on features in each layer, for example to
+   * emit in tilejson metadata stats.
+   */
   public void trackLayerStats(LayerAttrStats.Updater.ForZoom layerStats) {
     this.layerStatsTracker = layerStats;
   }

planetiler-core/src/main/java/com/onthegomap/planetiler/util/LayerAttrStats.java

@@ -61,6 +61,7 @@ public class LayerAttrStats {
       .toList();
   }
 
+  /** Shortcut for tests */
   void accept(String layer, int zoom, String key, Object value) {
     handlerForThread().forZoom(zoom).forLayer(layer).accept(key, value);
   }
@@ -160,7 +161,7 @@ public class LayerAttrStats {
 
     interface ForZoom {
 
-      ForZoom NO_OP = layer -> (key, value) -> {
+      ForZoom NOOP = layer -> (key, value) -> {
       };
 
       ForLayer forLayer(String layer);
@@ -171,7 +172,7 @@ public class LayerAttrStats {
     }
   }
 
-  public static class StatsForLayer {
+  private static class StatsForLayer {
 
     private final String layer;
     private final Map<String, FieldType> fields = new HashMap<>();