- Add unified Singleton support

git-svn-id: svn://svn.gna.org/svn/sgpemv2/trunk@643 3ecf2c5c-341e-0410-92b4-d18e462d057c

src/templates/parameter.tcc

@@ -1,4 +1,4 @@
-// Src/templates/parameter.tcc - Copyright 2005, 2006, University
+// src/templates/parameter.tcc - Copyright 2005, 2006, University
 //               of Padova, dept. of Pure and Applied
 //               Mathematics
 //

src/templates/singleton.hh

@@ -0,0 +1,59 @@
+// singleton.hh - Copyright 2005, 2006, University
+//               of Padova, dept. of Pure and Applied
+//               Mathematics
+//
+// 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; either version 2 of the License, or
+// (at your option) any later version.
+//
+// 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
+
+#ifndef SINGLETON_HH
+#define SINGLETON_HH 1
+
+#include <glibmm/thread.h>
+#include "config.h"
+
+namespace sgpem 
+{
+  
+  /** \brief An abstract implementation of the Singleton design pattern. 
+   * 
+   * Singleton implementers constuctor will have to declare friendliness 
+   * to Singleton::get_instance(). This also attempts to achieve 
+   * thread-safeness.
+   */
+  template<typename Instantiated_class>
+  class SG_DLLEXPORT Singleton 
+  {
+  public:
+  
+    /** \brief Ensures thread safety is respected, and returns the instantiated object 
+     *
+     * This is done by locking _instance via a mutex, before intantiating the 
+     * Instantiated_class attribute (if not done before).
+     *
+     * \return The instantiated object
+     */
+    static Instantiated_class& get_instance();
+
+  private:
+    static Instantiated_class* _instance;
+    static Glib::StaticMutex   _mutex;
+  }; //~ class Singleton
+
+} //~ namespace sgpem
+
+
+#include "singleton.tcc"
+
+#endif //~ SINGLETON_HH
+

src/templates/singleton.tcc

@@ -0,0 +1,45 @@
+// singleton.tcc - Copyright 2005, 2006, University
+//               of Padova, dept. of Pure and Applied
+//               Mathematics
+//
+// 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; either version 2 of the License, or
+// (at your option) any later version.
+//
+// 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
+
+#ifndef SINGLETON_TCC
+#define SINGLETON_TCC 1
+
+#include "singleton.hh"
+
+template<typename Instantiated_class>
+Instantiated_class*
+sgpem::Singleton<Instantiated_class>::_instance = NULL;
+
+template<typename Instantiated_class>
+Glib::StaticMutex
+sgpem::Singleton<Instantiated_class>::_mutex = GLIBMM_STATIC_MUTEX_INIT;
+
+
+template<typename Instantiated_class>
+Instantiated_class&
+sgpem::Singleton<Instantiated_class>::get_instance()
+{
+  Glib::Mutex::Lock lock(_mutex);
+  if(_instance == NULL)
+    _instance = new Instantiated_class();
+  return *_instance;
+}
+
+
+#endif //~ SINGLETON_TCC
+