code: public AstNode node( String name ) {
          CheckArg.isNotNull(name, "name");
          AstNode node = new AstNode(name);
          node.setProperty(JCR_PRIMARY_TYPE, NT_UNSTRUCTURED);
          return node;
      }
docs: Constructs an {@link AstNode} with the given string name
  
  @param name the name property of the node; may not be null
  @return the tree node