Added dictionary that stores created representations

Elements/src/DoorProperties.cs

@@ -0,0 +1,70 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Elements
+{
+    internal class DoorProperties
+    {
+        private readonly double _width;
+        private readonly double _height;
+        private readonly Material _material;
+        private readonly DoorOpeningSide _openingSide;
+        private readonly DoorOpeningType _openingType;
+
+        public DoorProperties(Door door)
+        {
+            _width = door.ClearWidth;
+            _height = door.ClearHeight;
+            _material = door.Material;
+            _openingSide = door.OpeningSide;
+            _openingType = door.OpeningType;
+        }
+
+        public override bool Equals(object obj)
+        {
+            if (!(obj is DoorProperties doorProps))
+            {
+                return false;
+            }
+
+            if (!_width.ApproximatelyEquals(doorProps._width))
+            {
+                return false;
+            }
+
+            if (!_height.ApproximatelyEquals(doorProps._height))
+            {
+                return false;
+            }
+
+            if (!_material.Id.Equals(doorProps._material.Id))
+            {
+                return false;
+            }
+
+            if (!_openingSide.Equals(doorProps._openingSide))
+            {
+                return false;
+            }
+
+            if (!_openingType.Equals(doorProps._openingType))
+            {
+                return false;
+            }
+
+            return true;
+        }
+
+        public override int GetHashCode()
+        {
+            int hash = 17;
+            hash = hash * 31 + _width.GetHashCode();
+            hash = hash * 31 + _height.GetHashCode();
+            hash = hash * 31 + _material.Id.GetHashCode();
+            hash = hash * 31 + _openingSide.GetHashCode();
+            hash = hash * 31 + _openingType.GetHashCode();
+            return hash;
+        }
+    }
+}

Elements/src/DoorRepresentationProvider.cs

@@ -9,14 +9,29 @@ namespace Elements
 {
     internal class DoorRepresentationProvider : RepresentationProvider<Door>
     {
-        public override List<RepresentationInstance> GetInstances(Door element)
+        private readonly Dictionary<DoorProperties, List<RepresentationInstance>> _doorTypeToRepresentations;
+
+        public DoorRepresentationProvider()
+        {
+            _doorTypeToRepresentations = new Dictionary<DoorProperties, List<RepresentationInstance>>();
+        }
+
+        public override List<RepresentationInstance> GetInstances(Door door)
         {
+            var doorProps = new DoorProperties(door);
+
+            if (_doorTypeToRepresentations.TryGetValue(doorProps, out var representations))
+            {
+                return representations;
+            }
+
             var representationInstances = new List<RepresentationInstance>()
             {
-                CreateSolidDoorRepresentation(element),
-                CreateCurveDoorRepresentation(element)
+                CreateSolidDoorRepresentation(door),
+                CreateCurveDoorRepresentation(door)
             };
 
+            _doorTypeToRepresentations[doorProps] = representationInstances;
             return representationInstances;
         }