// flatten.beh
//
// This file contains code which implements the Cd_graph flattening procedure.

Cd_graph {
{{
   // Creates the subclass to superclass edges.
   public void buildParentEdges() {
      TraversalGraph tg = new TraversalGraph(
         "from Cd_graph bypassing ParentList to Adjacency",
         Main.cg
      );
      tg.traverse(this, new BuildParentEdgesVisitor());

   }

   // Flattens the Cd_graph.
   public void flatten() {
      this.buildParentEdges();
      TraversalGraph tg = new TraversalGraph(
         "from Cd_graph to-stop Adjacency",
         Main.cg
      );
      tg.traverse(this, new PullDownVisitor());
   }

}}
}

// Visitor class which implements the Cd_graph::buildParentEdges() method.
BuildParentEdgesVisitor {
{{
   public void before(Adjacency a) {
      // Create TraversalGraph which targets the alternation neighbors.
      TraversalGraph tg = new TraversalGraph(
         "from Adjacency bypassing ParentList to Alternat_ns",
         Main.cg
      );
      Alternat_ns alt = (Alternat_ns) tg.fetch(a);

      // If alt == null, then this Adjacency is not a superclass, no need
      // to continue.
      if (alt != null) {
         // Iterate through each alternation neighbor.
         Enumeration e = alt.get_alternat_ns().elements();
         while (e.hasMoreElements()) {
            // sc points to a subclass.
            Adjacency sc = Main.cdg.search(((Term) e.nextElement()).fetchIdent());
            Neighbors_wc wc = (Neighbors_wc) sc.get_ns();
            // Add a to sc's list of parents.
            if (wc.get_parents() != null) {
               wc.get_parents().get_ps().addElement(a);
            }
            else {
               wc.set_parents(new ParentList());
               wc.get_parents().set_ps(new Adjacency_List());
               wc.get_parents().get_ps().addElement(a);
            }
         }
      }
   }

}}
}

// This Visitor pulls down all construction edges to their lowest level in the
// class hierarchy.
PullDownVisitor {
{{
   public void before(Adjacency a) {
      // If a has no superclass defined then there is nothing to do.
      if (a.fetchParents() != null) {
         // Create a TraversalGraph which targets the list of 
         // construction edges.
         TraversalGraph tg = new TraversalGraph(
            "from * bypassing ParentList to Any_vertex_List",
            Main.cg
         );

         // The variables myparts and parentparts point to a's
         // construction edges, and a's parents construction
         // edges, respectively.
         Any_vertex_List myparts = (Any_vertex_List) tg.fetch(a);
         Any_vertex_List parentparts = new Any_vertex_List();
 
         // Iterate through the parents construction edges and add
         // them to parentparts.         
         ListIterator i = tg.gather(a.fetchParents()).listIterator();
         while (i.hasNext()) {
            Enumeration e = ((Any_vertex_List) i.next()).elements();
            while (e.hasMoreElements())
               parentparts.addElement((Any_vertex) e.nextElement());
         }

         // Iterate through each parent construction edge and add it
         // to a.
         Enumeration e = parentparts.elements();
         while (e.hasMoreElements()) {
            myparts.addElement((Any_vertex) e.nextElement());
         }

         // Construction edges can now be removed from the parent.
         parentparts.set_first(null);
         
      }
   }

}}
}