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检查具有特定属性的对象是否已存在

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我的计划允许将足球教练分配给球队 .

private String name;
private Team team;

public Coach(String name, Team team){
    this.name = name;
    this.team = team;
}

如何检查具有特定 'Team' 的 'Coach' 对象是否已存在 . 我想阻止两名教练被分配到同一支队伍 .

String name = nameField.getText();
Team team = (Team) teamComboBox.getSelectedItem();

// I only want this to run, if the team doesn't already have a coach
Coach coach = new Coach(name, team);

我花了几个小时阅读类似的问题，但我无法获得任何代码工作 . 任何帮助将不胜感激，我正在拉我的头发 .

java object

3 回答

  • 0

    您需要告诉Java如何识别相同的对象，并且需要覆盖方法equals . 如果需要将哈希代码存储在HashMap或HashSet中，您可能还需要覆盖哈希代码 .

    回复于
  • 0

    例如，您需要使用Set for this

    Set<Team> teamsWithCoach = new HashSet<Team>();
  ...
  String name = nameField.getText();
  Team team = (Team) teamComboBox.getSelectedItem();

   if( !teamsWithCoach.contains(team) ) {
       Coach coach = new Coach(name, team); 
       teamsWithCoach.add(team);
   }
    回复于
  • 0

    你必须将你的教练存放在某种集合中 . 鉴于您所说的具体用例， Map<Team, Coach> 似乎是合适的：

    Map<Team, Coach> coachesByTeam = new HashMap<>();
if (!coachesByTeam.containsKey(team)) {
    Coach coach = new Coach(name, team);
    coachesByTeam.put(team, coach);
}
    回复于

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