diff -r 26f9a0ec4315 -r b8edf9de56c5 samples/stateful/src/org/apidesign/stateful/api/ProgressStateful.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/samples/stateful/src/org/apidesign/stateful/api/ProgressStateful.java	Sun May 02 14:35:48 2010 +0200
@@ -0,0 +1,53 @@
+package org.apidesign.stateful.api;
+
+/** API for notifying progress.
+ *
+ * @author Jaroslav Tulach <jtulach@netbeans.org>
+ */
+// BEGIN: progress.api
+public abstract class ProgressStateful {
+    public static ProgressStateful create(String name) {
+        return createImpl(name);
+    }
+    public abstract void start(int totalAmount);
+    public abstract void progress(int howMuch);
+    public abstract void finish();
+    // FINISH: progress.api
+
+    ProgressStateful() {
+    }
+    
+    private static ProgressStateful createImpl(String name) {
+        return new Impl(name);
+    }
+
+    private static final class Impl extends ProgressStateful {
+        private final String name;
+        private int total = -1;
+        private int current;
+
+        public Impl(String name) {
+            this.name = name;
+        }
+
+        @Override
+        public void start(int totalAmount) {
+            total = totalAmount;
+        }
+
+        @Override
+        public void progress(int howMuch) {
+            if (total == -1) {
+                throw new IllegalStateException("Call start first!");
+            }
+            current = howMuch;
+        }
+
+        @Override
+        public void finish() {
+            total = -1;
+            current = 0;
+        }
+
+    }
+}