Added SimpleObserver class.

This class works in the same way as the SimpleCommand class.
Use it with the makeObserver function.
It calls the receiver's member function when the subject sends
a signal.

1 files changed, 70 insertions, 0 deletions

diff --git a/src/FbTk/SimpleObserver.hh b/src/FbTk/SimpleObserver.hh
new file mode 100644
index 0000000..aafdf59
--- /dev/null
+++ b/src/FbTk/SimpleObserver.hh
@@ -0,0 +1,70 @@
+// SimpleObserver.hh
+// Copyright (c) 2008 Fluxbox Team (fluxgen at fluxbox dot 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.
+
+#include "Observer.hh"
+#include "SimpleCommand.hh"
+
+namespace FbTk {
+
+/** Functor for observers, instead of using this directly use makeObserver.
+ * Usage: 
+ * @code
+ * class SomeClass {
+ * public:
+ *    void doAction();
+ * };
+ *
+ * SomeClass some;
+ *
+ * Observer* obs = makeProxyObserver(some, &SomeClass::doAction);
+ * SomeSubject subj;
+ * subj.attach(obs);
+ * @endcode
+ */
+template <typename Receiver>
+class SimpleObserver: public Observer {
+public:
+    typedef void (Receiver::* Action)();
+    SimpleObserver(Receiver &r, Action a):
+        m_receiver(r), m_action(a) {
+        
+    }
+    void update(Subject *changedSubj) {
+        (m_receiver.*m_action)();
+    }
+private:
+    Receiver &m_receiver;
+    Action m_action;
+};
+
+// Helpers
+/** Creates an observer that takes no arguments.
+ * @param receiver The receiving instance.
+ * @param action A function in the receiving class.
+ * @return allocated simple observer. @see SimpleObserver
+ */
+template <typename Receiver, typename Action>
+Observer *makeObserver(Receiver &receiver, Action action) {
+    return new SimpleObserver<Receiver>( receiver, action );
+}
+
+}
+