diff --git a/vtm/src/org/oscim/tiling/ITileDataSink.java b/vtm/src/org/oscim/tiling/ITileDataSink.java
index 3bfbec5a..dac9e2b0 100644
--- a/vtm/src/org/oscim/tiling/ITileDataSink.java
+++ b/vtm/src/org/oscim/tiling/ITileDataSink.java
@@ -20,17 +20,25 @@ import org.oscim.backend.canvas.Bitmap;
 import org.oscim.core.MapElement;
 
 /**
- * MapDatabase callback (implemented by MapTileLoader)
- * .
- * NOTE: MapElement passed belong to the caller! i.e. dont hold
- * references to any of its data after callback function returns.
+ * ITileDataSink callbacks (implemented by MapTileLoader)
  */
 public interface ITileDataSink {
-
+	/**
+	 * Pass read MapElement data to loader.
+	 * <p>
+	 * NOTE: MapElement passed belong to the caller! i.e. dont hold references
+	 * to any of its data after callback function returns.
+	 */
 	void process(MapElement element);
 
+	/**
+	 * Pass read Bitmap data to loader.
+	 */
 	void setTileImage(Bitmap bitmap);
 
+	/**
+	 * Notify loader that tile loading is completed.
+	 */
 	void completed(QueryResult result);
 
 	public static enum QueryResult {