java - 如何使用泛型并从父类继承而不引起名称冲突？

Question

我有一个 Java 父类，名为 Flight 。我有 child 类:JetFlight , NormalFlight等继承自 Flight 。

我希望所有的 child 类(class)都实现 compareTo来自Comparable界面。我希望他们继承 Flight因为我想使用多态性(例如，启动 Flight 数组并用 JetFlight 、 NormalFlight 等对象填充它)。

这是我的父类代码:

public abstract class Flight  {
    public abstract int compareTo(Object o);
}

这是其中一个子类的代码:

public class JetFlight extends Flight implements Comparable<JetFlight> {
    private int flightTime;
    public JetFlight(int flightTime) {
        this.flightTime = flightTime;
    }
    public int compareTo(JetFlight j) {
        return this.flightTime - j.flightTime;
    }
}

由于两个错误，此代码无法编译:

1) compareTo(T) in 'java.lang.Comparable' clashes with 'compareTo(Object)' in 'Flight'; both objects have the same erasure, yet neither overrides the other.

2) Class 'JetFlight' must either be declared abstract or implement abstract method 'compareTo(Object)' in 'Flight'

当我想从一个类继承并同时在子类上使用泛型时，我该如何处理？

Answer 1

选项 1:由于您的比较是基于飞行时间，并且据我所知，变量飞行时间可以在父舱中推送，因为所有航类都具有此功能。然后在父类本身中实现compareTo()方法。

选项 2:如果您想保持当前代码不变:

    public abstract class Flight implements Comparable<Flight> {
    public abstract int compareTo(Flight o);
}

<小时/>

public class JetFlight extends Flight {
private int flightTime;
public JetFlight(int flightTime) {
    this.flightTime = flightTime;
}
public int compareTo(Flight f) {
    if(!(f instanceof JetFlight)){
        throw new IllegalArgumentException();
    }
    return this.flightTime - ((JetFlight)f).flightTime;
}