# HG changeset patch
# User Jaroslav Tulach <jtulach@netbeans.org>
# Date 1272803688 -7200
# Node ID 414d979b20b9d82516a33e66602dde430d3df465
# Parent  26f9a0ec4315bdc7603e562c2380766d24f6f4a5
Sample @StateChange annotation

diff -r 26f9a0ec4315 -r 414d979b20b9 samples/stateful/src/org/apidesign/stateful/api/ProgressStateMachine.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/samples/stateful/src/org/apidesign/stateful/api/ProgressStateMachine.java	Sun May 02 14:34:48 2010 +0200
@@ -0,0 +1,47 @@
+package org.apidesign.stateful.api;
+
+import java.lang.annotation.Documented;
+
+/**
+ *
+ * @author Jaroslav Tulach <jtulach@netbeans.org>
+ */
+// BEGIN: progress.annotations
+public abstract class ProgressStateMachine {
+    /** Annotation that helps users and IDEs to understand what
+     * is the allowed order of method calls on instances of given class.
+     */
+    @Documented
+    public @interface StateChange {
+        /** What is the required state of the object before given method
+         * is called.
+         * @return "*" means any state, otherwise specify the state's name
+         */
+        String from() default "*";
+        /** The state object enters after the method successfully returns.
+         * @return name of new state
+         */
+        String to();
+    }
+
+    @StateChange(to="ready")
+    public static ProgressStateMachine create(String name) {
+        return createImpl(name);
+    }
+
+    @StateChange(from="ready", to="started")
+    public abstract void start(int totalAmount);
+
+    @StateChange(from="started", to="started")
+    public abstract void progress(int howMuch);
+
+    @StateChange(to="finished")
+    public abstract void finish();
+    // FINISH: progress.annotations
+
+
+
+    private static ProgressStateMachine createImpl(String name) {
+        return null; // implementation left out, similar to Progress.java
+    }
+}