COMP: Add exception handling when reading boundary conditions file

Written-by: Sreekanth Arikatla <sreekanth.arikatla@kitware.com>

Base/DynamicalModels/ObjectModels/imstkFEMDeformableBodyModel.cpp

@@ -142,25 +142,38 @@ FEMDeformableBodyModel::loadBoundaryConditions()
     {
         std::ifstream file(fileName.data());
 
+        if (file.peek() == std::ifstream::traits_type::eof())
+        {
+            LOG(INFO) << "DeformableBodyModel::loadBoundaryConditions: The external boundary conditions file is empty";
+            return;
+        }
+
         if (file.is_open())
         {
             size_t index;
+            auto maxAllowed = m_vegaPhysicsMesh->getNumVertices();
             while (!file.eof())
             {
                 file >> index;
-                m_fixedNodeIds.emplace_back(index);
+                if (index < maxAllowed)
+                {
+                    m_fixedNodeIds.emplace_back(index);
+                }
+                else
+                {
+                    LOG(WARNING) << "FEMDeformableBodyModel::loadBoundaryConditions(): " <<
+                        "The boundary condition node id provided is greater than number of nodes and hence excluded!!";
+                }
             }
+
+            file.close();
+            std::sort(m_fixedNodeIds.begin(), m_fixedNodeIds.end());// for efficiency
         }
         else
         {
-            LOG(WARNING) << "DeformableBodyModel::loadBoundaryConditions: Could not open external file with boundary conditions";
-            return;
+            LOG(WARNING) << "DeformableBodyModel::loadBoundaryConditions: Could not open boundary conditions file!";
         }
-
-        file.close();
-        return;
     }
-
 }
 
 void