/**
  * Adds the given type declaration to the compilation unit. The list of types will be initialized
  * if it is <code>null</code>.
  *
  * @param cu compilation unit
  * @param type type declaration
  */
 public static void addTypeDeclaration(CompilationUnit cu, TypeDeclaration type) {
   List<TypeDeclaration> types = cu.getTypes();
   if (types == null) {
     types = new ArrayList<TypeDeclaration>();
     cu.setTypes(types);
   }
   types.add(type);
 }
 public CompilationUnitBuilder() {
   cu = new CompilationUnit();
   imports = new HashSet<String>();
   cu.setTypes(new ArrayList<TypeDeclaration>());
 }