make nodes to provide nodes instead of mixins

include/mixins/HierarchicalLinkMixin.h

@@ -6,39 +6,35 @@
 #include "links/OneToOneLink.h"
 #include "Logger.h"
 
-class HierarchicalLinkMixin : public LazyLinkMixin<OneToOneLink<ILinkMixin>> {
-public:
-	HierarchicalLinkMixin() {}
+template <class TElem>
+class HierarchicalLinkMixin : public LazyLinkMixin<OneToOneLink<TElem>> {
+	using LinkPtr = std::shared_ptr<ILink<TElem>>;
+	using ElemPtr = std::shared_ptr<TElem>;
 
+public:
 	~HierarchicalLinkMixin() override {
 		Logger::get("Mixin").dbg("--- Destructor called for: HierarchicalLinkMixin");
 	}
 
-	void linkChild(const MixinPtr& child) override {
+	void linkChild(const ElemPtr& child) override {
 		hierarchicalInit(child);
-		LazyLinkMixin<OneToOneLink<ILinkMixin>>::linkChild(child);
+		LazyLinkMixin<OneToOneLink<TElem>>::linkChild(child);
 	}
 
 protected:
-	void hierarchicalInit(const MixinPtr& child) {
+	void hierarchicalInit(const ElemPtr& child) {
 		Logger::get("Mixin").dbg("---  hierarchicalInit called");
 		if (this->link_ && !this->link_->getChildren().empty())
-			return; // already have children, do nothing
-
-
-		/* 1. Have no link_ —
-		 * 2. Has OneToOne with parent or not
-		 * 3. Has OneToOne with child
-		 */
+			return;
 
 		LinkPtr newLink;
 
 		if (typeid(*child) == typeid(*this)) {
 			Logger::get("Mixin").dbg("---  Mutate to OneToMany");
-			newLink = std::make_shared<OneToManyLink<ILinkMixin>>(this->getNode());
+			newLink = std::make_shared<OneToManyLink<TElem>>(this->getNode());
 		} else {
 			Logger::get("Mixin").dbg("---  Mutate to OneToOne");
-			newLink = std::make_shared<OneToOneLink<ILinkMixin>>(this->getNode());
+			newLink = std::make_shared<OneToOneLink<TElem>>(this->getNode());
 		}
 
 		if (newLink && this->link_)