code: public JSDocInfo build(boolean always) {
      if (populated || always) {
        checkState(currentInfo != null);
        JSDocInfo built = currentInfo;
        currentInfo = null;
        populateDefaults(built);
        populated = false;
        return built;
      } else {
        return null;
      }
    }
docs: Builds a {@link JSDocInfo} object based on the populated information and
  returns it.
  
  @param always Return an default JSDoc object.
  @return a {@link JSDocInfo} object populated with the values given to this
  builder. If no value was populated and {@code always} is false, returns
  {@code null}. If {@code always} is true, returns a default JSDocInfo.