@@ -0,0 +1,33 @@
+// Observer.cc for FbTk
+// Copyright (c) 2002 Henrik Kinnunen (fluxgen@fluxbox.org)
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the "Software"),
+// to deal in the Software without restriction, including without limitation
+// the rights to use, copy, modify, merge, publish, distribute, sublicense,
+// and/or sell copies of the Software, and to permit persons to whom the
+// Software is furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+// $Id: Observer.cc,v 1.1 2003/02/15 01:21:40 fluxgen Exp $
+
+#include "Observer.hh"
+#include "Subject.hh"
+
+namespace FbTk {
+
+Observer::~Observer() {
+    Subject::removeObserver(this); // make sure no subject has this observer attached
+}
+
+};

@@ -0,0 +1,39 @@
+// Observer.hh for FbTk
+// Copyright (c) 2002 Henrik Kinnunen (fluxgen@fluxbox.org)
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the "Software"),
+// to deal in the Software without restriction, including without limitation
+// the rights to use, copy, modify, merge, publish, distribute, sublicense,
+// and/or sell copies of the Software, and to permit persons to whom the
+// Software is furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+// $Id: Observer.hh,v 1.1 2003/02/15 01:21:40 fluxgen Exp $
+
+#ifndef FBTK_OBSERVER_HH
+#define FBTK_OBSERVER_HH
+
+namespace FbTk {
+
+class Subject;
+
+class Observer {
+public:
+    virtual ~Observer();
+    virtual void update(Subject *changedSubj) = 0;
+};
+
+}; // end namespace FBTK
+
+#endif // FBTK_OBSERVER_HH

@@ -0,0 +1,80 @@
+// Subject.cc for FbTk
+// Copyright (c) 2002 Henrik Kinnunen (fluxgen@fluxbox.org)
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the "Software"),
+// to deal in the Software without restriction, including without limitation
+// the rights to use, copy, modify, merge, publish, distribute, sublicense,
+// and/or sell copies of the Software, and to permit persons to whom the
+// Software is furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+// $Id: Subject.cc,v 1.1 2003/02/15 01:21:40 fluxgen Exp $
+
+#include "Subject.hh"
+#include "Observer.hh"
+
+#include <algorithm>
+#include <functional>
+
+namespace FbTk {
+
+Subject::SubjectList Subject::s_subjectlist;
+
+Subject::Subject() {
+    s_subjectlist.push_back(this);
+}
+
+Subject::~Subject() {
+    SubjectList::iterator it = s_subjectlist.begin();
+    SubjectList::iterator it_end = s_subjectlist.end();
+    for (; it != it_end; ++it) {
+        if (this == (*it)) {
+            s_subjectlist.erase(it);
+            break;
+        }
+    }
+}
+
+void Subject::attach(Observer *obj) {
+    m_observerlist.push_back(obj);
+    // no need to have more than one instance of an observer
+    std::unique(m_observerlist.begin(), m_observerlist.end());
+}
+
+void Subject::detach(Observer *obj) {
+    ObserverList::iterator it = m_observerlist.begin();
+    ObserverList::iterator it_end = m_observerlist.end();
+    for (; it != it_end; ++it) {
+        if (obj == (*it)) {
+            m_observerlist.erase(it);
+            break;
+        }
+    }
+}
+
+void Subject::notify() {
+    ObserverList::iterator it = m_observerlist.begin();
+    for (; it != m_observerlist.end(); ++it) {
+        (*it)->update(this);
+    }
+}
+
+void Subject::removeObserver(Observer *obj) {
+    SubjectList::iterator it = s_subjectlist.begin();
+    for(; it != s_subjectlist.end(); ++it) {
+        (*it)->detach(obj);
+    }
+}
+
+}; // end namespace FbTk

@@ -0,0 +1,54 @@
+// Subject.hh for FbTk
+// Copyright (c) 2002 Henrik Kinnunen (fluxgen@fluxbox.org)
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the "Software"),
+// to deal in the Software without restriction, including without limitation
+// the rights to use, copy, modify, merge, publish, distribute, sublicense,
+// and/or sell copies of the Software, and to permit persons to whom the
+// Software is furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+// $Id: Subject.hh,v 1.1 2003/02/15 01:21:40 fluxgen Exp $
+
+#ifndef FBTK_SUBJECT_HH
+#define FBTK_SUBJECT_HH
+
+#include <list>
+
+namespace FbTk {
+
+class Observer;
+
+class Subject {
+public:
+    Subject();
+    virtual ~Subject();
+    /// attach an observer
+    void attach(Observer *obs);
+    /// detach an observer
+    void detach(Observer *obs);
+    /// notify all attached observers
+    void notify();
+    static void removeObserver(Observer *obs);
+private:
+    typedef std::list<Observer *> ObserverList;
+    ObserverList m_observerlist;
+
+    typedef std::list<Subject *> SubjectList;
+    static SubjectList s_subjectlist;
+};
+
+}; // end namespace FbTk
+
+#endif // FBTK_SUBJECT_HH