add propertyNamesSpliterator (#1369)

src/main/java/tools/jackson/core/TreeNode.java

@@ -6,6 +6,8 @@
 package tools.jackson.core;
 
 import java.util.Iterator;
+import java.util.Spliterator;
+import java.util.Spliterators;
 
 /**
  * Marker interface used to denote JSON Tree nodes, as far as
@@ -227,6 +229,19 @@ public interface TreeNode
      */
     Iterator<String> propertyNames();
 
+    /**
+     * Method for accessing names of all properties for this node via a <code>Spliterator</code> ,
+     * if (and only if) this node is an Object node. Number of property names accessible
+     * will be {@link #size}.
+     *
+     * @return A <code>Spliterator</code> for traversing names of all properties this Object node
+     *   has (if Object node); empty {@link Spliterator} otherwise (never {@code null}).
+     * @since 3.0
+     */
+    default Spliterator<String> propertyNamesSpliterator() {
+        return Spliterators.spliteratorUnknownSize(propertyNames(), Spliterator.ORDERED);
+    }
+
     /**
      * Method for locating node specified by given JSON pointer instances.
      * Method will never return null; if no matching node exists,