diff --git a/XObject.java b/XObject.java
index 97caa52..5031439 100644
--- a/XObject.java
+++ b/XObject.java
@@ -6,6 +6,14 @@ import java.util.List;
 
 public class XObject {
 
+    public enum XObjectType
+    {
+        XOT_SIMPLE,
+        XOT_ARRAY,
+        XOT_OBJECT
+    }
+
+    private XObjectType type;
     private XValue xValue;
     private ArrayList arrayValue;
     private HashMap objectValue;