1 files changed, 41 insertions, 0 deletions
diff --git a/docs/modules/ROOT/examples/observer/SubjectObserverProtocol.java b/docs/modules/ROOT/examples/observer/SubjectObserverProtocol.java
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+++ b/docs/modules/ROOT/examples/observer/SubjectObserverProtocol.java
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+/*
+Copyright (c) Xerox Corporation 1998-2002.  All rights reserved.
+
+Use and copying of this software and preparation of derivative works based
+upon this software are permitted.  Any distribution of this software or
+derivative works must comply with all applicable United States export control
+laws.
+
+This software is made available AS IS, and Xerox Corporation makes no warranty
+about the software, its performance or its conformity to any specification.
+*/
+
+package observer;
+
+import java.util.Vector;
+
+abstract aspect SubjectObserverProtocol {
+
+    abstract pointcut stateChanges(Subject s);
+
+    after(Subject s): stateChanges(s) {
+        for (int i = 0; i < s.getObservers().size(); i++) {
+            ((Observer)s.getObservers().elementAt(i)).update();
+        }
+    }
+
+    private Vector Subject.observers = new Vector();
+    public void   Subject.addObserver(Observer obs) {
+        observers.addElement(obs);
+        obs.setSubject(this);
+    }
+    public void   Subject.removeObserver(Observer obs) {
+        observers.removeElement(obs);
+        obs.setSubject(null);
+    }
+    public Vector Subject.getObservers() { return observers; }
+
+    private Subject Observer.subject = null;
+    public void     Observer.setSubject(Subject s) { subject = s; }
+    public Subject  Observer.getSubject() { return subject; }
+}