/// <summary>
        /// Get a factor tree node by the specified factor id.
        /// </summary>
        /// <param name="userContext">
        /// Information about the user that makes this method call.
        /// </param>
        /// <param name="factorId">The specified factor id.</param>
        /// <returns>A factor tree node related to the specified factor id.</returns>
        public override IFactorTreeNode GetFactorTree(IUserContext userContext, int factorId)
        {
            IFactorTreeNode    factorTreeNode = null;
            FactorTreeNodeList factorTrees    = null;
            Dictionary <int, IFactorTreeNode> factorTreeNodes = new Dictionary <int, IFactorTreeNode>();
            IFactorTreeSearchCriteria         searchCriteria;

            searchCriteria           = new FactorTreeSearchCriteria();
            searchCriteria.FactorIds = new List <Int32>();
            searchCriteria.FactorIds.Add(factorId);

            Boolean getOnlyPublicFactors = !IsUserAuthorizedToReadNonPublicFactors(userContext);

            // Get cached factor trees
            factorTrees    = GetFactorTrees(userContext.Locale, getOnlyPublicFactors);
            factorTreeNode = GetFactorTreeNode(userContext.Locale, factorId, getOnlyPublicFactors);

            if (factorTrees.IsNull())
            {
                // Get factor trees based on user role and rights (get public factors or all factors)
                factorTrees = base.GetFactorTrees(userContext);

                // Store factor trees in cache
                SetFactorTrees(factorTrees, userContext.Locale, getOnlyPublicFactors);

                foreach (IFactorTreeNode node in factorTrees)
                {
                    if (!factorTreeNodes.ContainsKey(node.Id))
                    {
                        factorTreeNodes.Add(node.Id, node);
                    }

                    AddFactorTreeChildren(factorTreeNodes, node.Children);
                }

                // Store factor tree nodes in cache
                SetFactorTreeNodes(factorTreeNodes, userContext.Locale, getOnlyPublicFactors);
            }

            if (factorTrees.IsNotNull())
            {
                foreach (var factorTree in factorTrees)
                {
                    if (factorTree.Id == factorId)
                    {
                        factorTreeNode = factorTree;
                        break;
                    }
                }
            }

            if (factorTreeNode.IsNull() && factorTreeNodes.IsNotNull())
            {
                foreach (var factorTree in factorTreeNodes)
                {
                    if (factorTree.Key == factorId)
                    {
                        factorTreeNode = factorTree.Value;
                        break;
                    }
                }
            }

            return(factorTreeNode);
        }