diff -r c20d1d8ef2ca -r 40cabcdcd2be samples/openfixed/src/org/apidesign/openfixed/ModificationEvent.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/samples/openfixed/src/org/apidesign/openfixed/ModificationEvent.java	Thu Oct 30 21:30:10 2014 +0100
@@ -0,0 +1,35 @@
+package org.apidesign.openfixed;
+
+import java.util.Collection;
+import java.util.EventObject;
+
+// BEGIN: openfixed.event
+public final class ModificationEvent extends EventObject {
+    private final int delta;
+    ModificationEvent(Object source, int delta) {
+        super(source);
+        this.delta = delta;
+    }
+    
+    public int getChange() {
+        return delta;
+    }
+    
+// FINISH: openfixed.event
+    
+// BEGIN: openfixed.addgetter    
+    int pending;
+    /** @since 2.0 */
+    public int getPending() {
+        return pending;
+    }
+// END: openfixed.addgetter    
+    
+// BEGIN: openfixed.mount
+    Collection<PostModificationListener> posts;
+    /** @since 3.0 */
+    public void postProcess(PostModificationListener p) {
+        posts.add(p);
+    }
+// END: openfixed.mount  
+}