java - 如何使用 arraylist 作为字段有效地深度克隆对象数组

Question

最深元素:

class Player {
    //fields contain:
    int value;
}

收集于:

class Team {
    //fields contain:
    ArrayList<Player> players;
}

收集于:

class Splitter {
    //fields contain:
    Teams[] teams;
}

在 Splitter 的函数中，我必须克隆 teams。我基本上必须通过克隆每个 Team 对象来克隆数组 teams，每个对象都包含一个我必须克隆的 ArrayList players。我不想想要克隆 Player 对象本身。

到目前为止我的解决方案看起来像这样:

private Team[] deepClone(Team[] teams) {
    Team[] new_teams = new Team[teams.length];
    for (int i = 0; i < teams.length; i++) {
        new_teams[i] = new Team();
        for (Player player : teams[i].getPlayers())
            new_teams[i].getPlayers().add(player);
    }
    return new_teams;
}

我可以做哪些改变来使其更高效或更优雅？

Answer 1

您当前的解决方案相当于以下更简单的形式:

private Team[] deepClone(Team[] teams) {
    Team[] new_teams = new Team[teams.length];
    for (int i = 0; i < teams.length; i++) {
        new_teams[i] = new Team();
        new_teams[i].getPlayers().addAll(teams[i].getPlayers());
    }
    return new_teams;
}

您可以使用流和 lambda 使其更加优雅，而无需循环索引:

private Team[] deepClone(Team[] teams) {
    return Stream.of(teams).map(team -> {
        Team newTeam = new Team();
        return newTeam.getPlayers().addAll(team.getPlayers());
    }).toArray(Team[]::new);
}