如何更新数据表中的元素

Question

我试图遵循Cucumber教程中的一个例子，但它是为Ruby编写的，我试图用Java编写它。我在执行@When步骤时遇到困难，因为它需要我更新DataTable，并且引发了以下异常：

java.lang.UnsupportedOperationException
at java.base/java.util.Collections$UnmodifiableList.set(Collections.java:1308)
at cucumber_tutorial.expressive_scenarios.chapter5.features.step_definitions.BoardSteps.player_x_plays_in_row_column(BoardSteps.java:36)
at ✽.When player x plays in row 2, column 1(tic_tac_toe.feature:8)

我的特色如下：

Feature:
  Scenario:
    Given a board like this:
      |   | 1 | 2 | 3 |
      | 1 |   |   |   |
      | 2 |   |   |   |
      | 3 |   |   |   |
    When player x plays in row 2, column 1
    Then the board should look like this:
      |   | 1 | 2 | 3 |
      | 1 |   |   |   |
      | 2 | x |   |   |
      | 3 |   |   |   |

运行该功能并获取生成的代码片段后，我有以下内容（我自己也添加了几行代码）

package cucumber_tutorial.expressive_scenarios.chapter5.features.step_definitions;

import cucumber.api.DataTable;
import cucumber.api.java.en.Given;
import cucumber.api.java.en.Then;
import cucumber.api.java.en.When;
import java.util.List;

public class BoardSteps {

    List<List<String>> boardList;

    @Given("^a board like this:$")
    public void a_board_like_this(DataTable dataTable) throws Throwable {
        boardList = dataTable.raw();
        System.out.println(boardList);
        // Write code here that turns the phrase above into concrete actions
        // For automatic transformation, change DataTable to one of
        // List<YourType>, List<List<E>>, List<Map<K,V>> or Map<K,V>.
        // E,K,V must be a scalar (String, Integer, Date, enum etc)
        //throw new PendingException();
    }

    @When("^player x plays in row (\\d+), column (\\d+)$")
    public void player_x_plays_in_row_column(int row, int col) throws Throwable {
        // Write code here that turns the phrase above into concrete actions
        //board.
        //throw new PendingException()
        boardList.get(row).set(col, "x");
    }

    @Then("^the board should look like this:$")
    public void the_board_should_look_like_this(DataTable expectedTable) throws Throwable {
        // Write code here that turns the phrase above into concrete actions
        // For automatic transformation, change DataTable to one of
        // List<YourType>, List<List<E>>, List<Map<K,V>> or Map<K,V>.
        // E,K,V must be a scalar (String, Integer, Date, enum etc)
        expectedTable.diff(boardList);
        //throw new PendingException();
    }

}

问题似乎是@Given步骤中的dataTable.raw()为boardList分配了一个不可修改的集合类型，因此使其不可更新。 Ruby的例子就是，​

row, col = row.to_i, col.to_i​   
@board[row][col] = ​'x'​

我的异常是从

boardList.get(row).set(col, "x"); //this line throws the exception

有人能告诉我使用Java更新数据表的标准方法是什么吗