public void addBefore(GeoBlockEntry entry)
 {
     setPrev(entry.getPrev());
     setNext(entry);
     //
     entry.getPrev().setNext(this);
     entry.setPrev(this);
 }
 public void setPrev(GeoBlockEntry entry)
 {
     _prev = entry;
 }
 public void setNext(GeoBlockEntry entry)
 {
     _next = entry;
 }