protected void createRootNode(EntityType label, String value) {
   fRoot = new Node(label, value);
   fRoot.setEntity(new SourceCodeEntity(value, label, new SourceRange()));
 }
 protected Node getFirstLeaf() {
   return ((Node) fRoot.getFirstLeaf());
 }
 protected Node getLastChild() {
   return (Node) fRoot.getLastChild();
 }
 protected String getTreeString() {
   return fRoot.print(new StringBuilder()).toString();
 }