introduced general body dispatcher

src/pe/utility/BodyDispatcher.h

+//======================================================================================================================
+//
+//  This file is part of waLBerla. waLBerla 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 3 of
+//  the License, or (at your option) any later version.
+//
+//  waLBerla 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 waLBerla (see COPYING.txt). If not, see <http://www.gnu.org/licenses/>.
+//
+//! \file BodyDispatcher.h
+//! \author Sebastian Eibl <sebastian.eibl@fau.de>
+//
+//======================================================================================================================
+
+#pragma once
+
+#include <core/DataTypes.h>
+#include <pe/rigidbody/RigidBody.h>
+
+#include <boost/tuple/tuple.hpp>
+
+namespace walberla {
+namespace pe {
+
+template < typename TypeList, typename Functor, typename ReturnType >
+class SingleDispatch
+{
+public:
+   static ReturnType execute(const id_t typeID, Functor& func){
+      static_assert(boost::is_base_of<RigidBody, typename TypeList::head_type>::value, "only downcasting allowed!");
+      if (TypeList::head_type::getStaticTypeID() == typeID)
+      {
+         typedef typename TypeList::head_type BodyType;
+         BodyType* bd = NULL;
+         return func( static_cast<BodyType *>( bd ) );
+      } else
+      {
+         return SingleDispatch<typename TypeList::tail_type, Functor, ReturnType>::execute(typeID, func);
+      }
+   }
+
+   static ReturnType execute(RigidBody* bd, Functor& func){
+      static_assert(boost::is_base_of<RigidBody, typename TypeList::head_type>::value, "only downcasting allowed!");
+      if (TypeList::head_type::getStaticTypeID() == bd->getTypeID())
+      {
+         typedef typename TypeList::head_type BodyType;
+         return func( static_cast<BodyType *>(bd) );
+      } else
+      {
+         return SingleDispatch<typename TypeList::tail_type, Functor, ReturnType>::execute(bd, func);
+      }
+   }
+
+   static ReturnType execute(const RigidBody* bd, Functor& func){
+      static_assert(boost::is_base_of<RigidBody, typename TypeList::head_type>::value, "only downcasting allowed!");
+      if (TypeList::head_type::getStaticTypeID() == bd->getTypeID())
+      {
+         typedef typename TypeList::head_type BodyType;
+         return func( static_cast<const BodyType *>(bd) );
+      } else
+      {
+         return SingleDispatch<typename TypeList::tail_type, Functor, ReturnType>::execute(bd, func);
+      }
+   }
+};
+
+template < typename Functor, typename ReturnType >
+struct SingleDispatch< boost::tuples::null_type, Functor, ReturnType >{
+   static ReturnType execute(const id_t typeID, Functor& /*func*/)
+   {
+      WALBERLA_ABORT("SingleDispatch: BodyType could not be determined (" << typeID << ")");
+      return ReturnType();
+   }
+
+   static ReturnType execute(RigidBody* bd, Functor& /*func*/)
+   {
+      WALBERLA_ABORT("SingleDispatch: Type of body " << bd->getSystemID() << " could not be determined (" << bd->getTypeID() << ")");
+      return ReturnType();
+   }
+   static ReturnType execute(const RigidBody* bd, Functor& /*func*/)
+   {
+      WALBERLA_ABORT("SingleDispatch: Type of body " << bd->getSystemID() << " could not be determined (" << bd->getTypeID() << ")");
+      return ReturnType();
+   }
+};
+
+}  // namespace pe
+}  // namespace walberla