code: protected void validateGenerationType(GenerationType generationType) {
      if (generationType == null) {
        return;
      }
      if (generationType == GenerationType.IDENTITY) {
        if (!dialect.supportsIdentity()) {
          throw new GenException(Message.DOMAGEN0003, dialect.getName());
        }
      } else if (generationType == GenerationType.SEQUENCE) {
        if (!dialect.supportsSequence()) {
          throw new GenException(Message.DOMAGEN0004, dialect.getName());
        }
      }
    }
docs: 識別子を生成する方法を検証します。
  
  @param generationType 識別子を生成する方法