the begginning

writeengine/server/we_observer.h

@@ -0,0 +1,68 @@
+/* Copyright (C) 2014 InfiniDB, Inc.
+
+   This program is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License
+   as published by the Free Software Foundation; version 2 of
+   the License.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+   MA 02110-1301, USA. */
+
+/*******************************************************************************
+* $Id$
+*
+*******************************************************************************/
+
+/*
+ * Observer.h
+ *
+ *  Created on: Oct 5, 2011
+ *      Author: bpaul@calpont.com
+ */
+
+#ifndef OBSERVER_H_
+#define OBSERVER_H_
+
+#include <list>
+using namespace std;
+
+
+namespace WriteEngine
+{
+
+class Subject; 	// forward deceleration
+
+class Observer {
+public:
+	virtual ~Observer();
+	virtual bool update(Subject* pSub)=0;
+
+protected:
+	Observer();
+};
+
+class Subject {
+public:
+	Subject();
+	virtual ~Subject();
+
+	virtual void attach(Observer* Obs);
+	virtual void detach(Observer* Obs);
+	virtual void notify();
+
+
+private:
+	typedef std::list<Observer*> Observers;
+	Observers fObs;
+};
+
+}
+
+#endif /* OBSERVER_H_ */