diff -N ExpandedIdentifier.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ ExpandedIdentifier.java	7 Feb 2006 17:03:30 -0000	1.1
@@ -0,0 +1,9 @@

+package org.lcsim.geometry;
+
+import java.util.Set;
+
+public interface ExpandedIdentifier
+{
+    public int get(String field);  
+    public Set<String> fields();
+}

diff -N ExpandedIdentifier.java
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ ExpandedIdentifier.java	7 Feb 2006 17:03:30 -0000	1.1
@@ -0,0 +1,29 @@

+package org.lcsim.geometry.util;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Set;
+
+public class ExpandedIdentifier
+implements org.lcsim.geometry.ExpandedIdentifier
+{
+    Map<String, Integer> map = new HashMap<String, Integer>();
+    
+    public ExpandedIdentifier()
+    {}
+
+    protected void put(String field, int value)
+    {
+        map.put(field, value);
+    }
+    
+    public int get(String field)
+    {
+        return map.get(field);        
+    }      
+    
+    public Set<String> fields()
+    {
+        return map.keySet();
+    }       
+}