// return the physical node of the source vnode of the virtual 
// adjacency in the ring.

*operation* Node* get_phys_node()
*wrapper* VirtualAdjacency
  (@
     VNode* vnode = this->get_source();
     return_val = vnode->get_phys_node();
   @)


// find the adjacency of a given node 

*operation* Adjacency* find(Node* node)
*init* (@ NULL @)
*traverse*
  *from* Network
  *to* Adjacency
*wrapper* Adjacency
  (@ if (get_source() == node)
       return_val=this; @)

*operation* Tree_Adjacency* find(Node* node)
*init* (@ NULL @)
*traverse*
  *from* Tree
  *to* Tree_Adjacency
*wrapper* Tree_Adjacency
  (@ if (get_source() == node)
       return_val = this; @)

*operation* VirtualAdjacency* find(VNode* vnode)
*init* (@ NULL @)
*traverse*
  *from* Ring
  *to-stop* VirtualAdjacency
*wrapper* VirtualAdjacency
  (@ if (get_source() == vnode)
       return_val = this;
  @)




// return the first virtual node of a physical node

*operation* VNode* first_vnode()
*wrapper* Node
  (@ return_val = this->get_vnodes()->car(); @)


// return the last virtual node of a physical node

*operation* VNode* last_vnode()
*wrapper* Node
  (@ return_val = get_vnodes()->lastexp(); @)


// return the virtual adjacency of the next default virtual node
// on the ring.

*operation* VirtualAdjacency* get_nextdefault(VirtualAdjacency* adj)
*init* (@ NULL @)
*traverse*
  *from* Ring
  *to-stop* VirtualAdjacency
*carry* *inout* int pos = (@ 0 @), 
        *inout* int count = (@ 0 @)
*along* 
  *from* Ring
  *to-stop* VirtualAdjacency
*wrapper* Ring
  *suffix*
  (@
     // the next default is the adjacency in position pos+1
     pos++;
     VirtualAdjacency_List* vadj_list = get_start();
     if (pos > count)
       pos = 1;
     return_val = vadj_list->n_th(pos);
  @)
*wrapper* VirtualAdjacency
  (@ 
    count++;
    if (this == adj) {
      pos = count;
    }
  @)

// return the virtual adjacency of the previous default virtual node
// on the ring.

*operation* VirtualAdjacency* get_prevdefault(VirtualAdjacency* adj)
*init* (@ NULL @)
*traverse*
  *from* Ring
  *to* VirtualAdjacency
*carry* *inout* VirtualAdjacency* prev_adj = (@ get_start()->lastexp() @)
*along* 
  *from* Ring
  *to* VirtualAdjacency
*wrapper* VirtualAdjacency
  (@
     if (this == adj)
       return_val = prev_adj;
     else
       prev_adj = this;
  @)