使arraylist get方法工作和其他问题

Question

用户：

has a username e.g 'fj3'
has a userType which can be: 'user', 'editor' or 'admin'
has a name e.g 'Francis'
has a constructor which takes the username, userType and name as parameters
has a getUsername() method
has a getUserType() method
has a getName() method
has a setUserType() method which takes one of the user types as a parameter 

2）编写UserGroup类

UserGroup类必须有用户的ArrayList。

package user;
public class User{
    public enum UserType{                           
        ADMIN, EDITOR, USER;
    }

    private String id;                             
    private UserType userPermissions;               
    private String actualName;                      

    public User(String username, UserType userType, String name){
        id = username;
        userPermissions = userType;
        actualName= name;
    } 

    public String getUsername(){
        return id;
    }

    public UserType getUserType(){
        return userPermissions;
    }       

    public String getName(){
        return actualName;
    }

    public void setUserType(UserType input){
        userPermissions = input;
    }
}

和我的UserGroup类：

package user;
import java.util.*;
import user.User.UserType; 

public class UserGroup{

    private ArrayList<User> people;

    public UserGroup(){
        people = new Arraylist<User>();
    }

    public static void addSampleData(String username, UserType userType, String name){
        people.add(new User(username, userType,name));
    }

    public User get(int){
        return User; 
    }

    public void printUsernames(){
        for (User user: groupArray){
            System.out.printf("%s %s\n", user.getUsername(), user.getuserType);
        }
    } 
}

这显然远远没有完成，但我完全被困住了。我的第一个问题是我不确定如何为此编写get方法。请帮帮我！！我认为我的User类很好，但我的UserGroup类远没有完成所有的目标，我不知道如何实现它们！！

Answer 1

到目前为止看起来不错，一些修正：

AddSampleData()方法不应该是静态的，因为它使用类的非静态成员。请求还声明添加示例数据本身。

getUser()非常简单。

public void addSampleData() {
    people.add(new User("pe3", UserType.ADMIN,"Peter"));
    people.add(new User("u987", UserType.EDITOR,"Udo"));
    people.add(new User("frank123", UserType.USER,"Frank"));
    // repeat ...
}

public User getUser(int idx) {
    return people.get(idx); 
}

public void printUsernames(){
    for (User user: people){
        System.out.printf("%s %s\n", user.getUsername(), user.getuserType);
    }
} 

UserGroup grp = new UserGroup();
grp.addSampleData();
grp.printUsernames();
User u1 = grp.getUser(0);