java - java 中的抽象类 getter 和 setter

Question

所以，解释一下我的代码 ->

我有一个 Employee 类型的抽象类，它有自己的字段，例如姓名。

然后，我有从 Employee 扩展的 Admin、Sales 和 Manager 类。每个都有自己的字段，例如管理员的固定奖金、销售的百分比奖金和经理的员工数组列表。

然后我有一个驱动程序类，其中包含员工的 ArrayList，因此它包含管理员、销售人员和经理。

我的问题出现在 Arraylist 元素上。假设我从 ArrayList 中获取 Admin 类的一名员工，并尝试使用 getter getFixedBonus() 获取他们的fixedBonus 字段，我根本做不到。我怎样才能做到这一点，以便我可以使用特定于类的 getter 和 setter，而不仅仅是继承的 getter 和 setter？这是我的代码的副本，其中出现了问题。具体来说，问题出在 switch 语句的 case 5 和 case 6 中。

private Employee editAnEmployee(Employee emp) {
    boolean exit = false;
    boolean validChoice = false;
    int choice = 0;
    Boolean sure = false; // used in the switch statement
    String newName;
    double newValue;
    Employee admin = new AdminWorker("0", "0", 0, 0, 0); // these are used
    Employee sales = new SalesWorker("0", "0", 0, 0, 0, 0); // to check the
    Employee manager = new Manager("0", "0", 0, 0); // class of the
                                                    // employee
                                                    // being sent
                                                    // in, to edit
                                                    // the fields
                                                    // the employee
                                                    // may hold
    do {
        do {
            validChoice = true;
            emp.toString();
            StdOut.println("Which field would you like to edit?");
            StdOut.println("1) First Name.");
            StdOut.println("2) last Name.");
            StdOut.println("3) Hourly rate.");
            StdOut.println("4) Hours worked in the last week.");
            if (emp.getClass().equals(admin)) {
                StdOut.println("5) Fixed Bonus.");
            } else if (emp.getClass().equals(sales)) {
                StdOut.println("5) Percentage bonus on sales.");
                StdOut.println("6) Value of sales made in the last week.");
            } else if (emp.getClass().equals(manager)) {
                StdOut.println("5) Department.");
            }
            StdOut.println("0) Exit.");
            choice = StdIn.readInt();
            if (choice < 0 || choice > 4) {
                if (emp.getClass().equals(admin) && choice <= 5) {
                    validChoice = true;
                } else if (emp.getClass().equals(sales) && choice <= 6) {
                    validChoice = true;
                } else if (emp.getClass().equals(manager)) {
                    validChoice = true;
                } else {
                    StdOut.println("You entered an invalid number! Try Again...");
                    validChoice = false;
                }
            }
        } while (!validChoice);
        switch (choice) {
        case 0:
            StdOut.println("You are now exiting...");
            exit = true;
            break;
        case 1:
            StdOut.println("The employees first name is: " + emp.getFirstName() + ". What would you like the first name to be now?");
            newName = StdIn.readString();
            StdOut.println("Are you sure you want to change " + emp.getFirstName() + " to " + newName +"?(y/n)");
            sure = ynChoice();
            if(sure) emp.setFirstName(newName);
            break;
        case 2:
            StdOut.println("The employees last name is: " + emp.getLastName() + ". What would you like the last name to be now?");
            newName = StdIn.readString();
            StdOut.println("Are you sure you want to change " + emp.getLastName() + " to " + newName +"?(y/n)");
            sure = ynChoice();
            if(sure) emp.setLastName(newName);
            break;
        case 3:
            StdOut.println("The employees hourly rate is: " + emp.getHourlyRate() + ". What would you like the hourly rate to be now?");
            newValue = StdIn.readDouble();
            StdOut.println("Are you sure you want to change " + emp.getHourlyRate() + " to " + newValue +"?(y/n)");
            sure = ynChoice();
            if(sure) emp.setHourlyRate(newValue);
            break;
        case 4:
            StdOut.println("The employee has worked: " + emp.getHoursWorked() + " hours in the last week. What would you like that to be now?");
            newValue = StdIn.readDouble();
            StdOut.println("Are you sure you want to change " + emp.getHoursWorked() + " to " + newValue +"?(y/n)");
            sure = ynChoice();
            if(sure) emp.setHoursWorked(newValue);
            break;
        case 5:
            if (emp.getClass().equals(admin)) {
                StdOut.println("The employees fixed bonus is: " + emp.getFixedBonus() + ". What would you like that to be now?");
                newValue = StdIn.readDouble();
                StdOut.println("Are you sure you want to change " + emp.getFixedBonus() + " to " + newValue +"?(y/n)");
                sure = ynChoice();
                if(sure) emp.setHoursWorked(newValue);
            } else if (emp.getClass().equals(sales)) {
                StdOut.println("The employees percentage bonus is: " + emp.getPercentageBonus() + ". What would you like that to be now?");
                newValue = StdIn.readDouble();
                StdOut.println("Are you sure you want to change " + emp.getPercentageBonus() + " to " + newValue +"?(y/n)");
                sure = ynChoice();
                if(sure) emp.setHoursWorked(newValue);
            } else if (emp.getClass().equals(manager)) {
                StdOut.println("The employees fixed bonus is: " + emp.getFixedBonus() + ". What would you like that to be now?");
                newValue = StdIn.readDouble();
                StdOut.println("Are you sure you want to change " + emp.getFixedBonus() + " to " + newValue +"?(y/n)");
                sure = ynChoice();
                if(sure) emp.setHoursWorked(newValue);
            }
            break;
        case 6:
            StdOut.println("The employees sales in the last week are: " + emp.getLastWeeksSales() + ". What would you like that to be now?");
            newValue = StdIn.readDouble();
            StdOut.println("Are you sure you want to change " + emp.getLastWeeksSales() + " to " + newValue +"?(y/n)");
            sure = ynChoice();
            if(sure) emp.setHoursWorked(newValue);
            break;
        }
    } while (!exit);
    return emp;
}

Answer 1

我认为 instanceof 关键字可能对您的情况有用。

ArrayList<Employee> list; // This is initialized and has Employees

for (Employee person: list) {
    if (person instanceof Admin) {
        int fixedBonus = ((Admin) person).getFixedBonus();

        // Do something here
    }
}

这能回答你的问题吗？ (你不需要 .getClass().equals()，这就是 instanceof 的作用:D )