digraph "Abstract" {
  rankdir="BT"
  node [ratio="auto" shape=record margin=0; href="javascript:Action.selectClass(&quot;\N&quot;);"];

  // Class: X
  "X" [shape=plaintext margin=0 label=<<table border="1" cellspacing="0" cellborder="0" cellpadding="2"><tr><td cellpadding="4">    X    </td></tr><tr><td cellpadding="4">&laquo;abstract&raquo;</td></tr><hr/><tr><td align="left" href="" title="String a&#13;">  a : String  </td></tr></table>>,
   tooltip="class X
"];

  // Class: Y
  "Y" [shape=plaintext margin=0 label=<<table border="1" cellspacing="0" cellborder="0" cellpadding="2"><tr><td cellpadding="4">    Y    </td></tr><hr/><tr><td align="left" href="" title="String b&#13;">  b : String  </td></tr></table>>,
   tooltip="class Y
"];
  "Y" -> "X" [arrowhead="empty"; samehead="gen"];


  // All associations
}
