Added NullNode class to be able to remember createtime per

cached null reference.

src/helma/objectmodel/db/NullNode.java

@@ -0,0 +1,87 @@
+// NullNode.java
+// Copyright (c) Hannes Wallnöfer 2001
+ 
+package helma.objectmodel.db;
+
+import helma.objectmodel.*;
+
+/**
+ * This class represents a null node reference in the object cache
+ */
+ 
+public class NullNode extends Node {
+
+
+    public NullNode () {
+    }
+
+
+}
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+