Java如何將父類變量的值傳遞給繼承對象

Question

我正在做空中交通塔演習。 我有一個帶有兩個變量id和idCounter的Aircraft類。 該類由其他3個類繼承-3種飛機類型。 我使用工廠設計模式從這3種類型中的每一種創建對象，對象在創建時保存在ArrayList中。 每個對象都應該有一個唯一的ID，而我應該使用idCounter，以確定它。

我寫了以下方法

public long nextId() {
    setIdCounter(getIdCounter()+1);
    return idCounter;
}

public void setId(long id) {
    Id = nextId();
}

問題是我似乎無法更新對象的ID，所有ID都停留在0。

我嘗試用以下方法調用set方法

arrayName.get(i).setId(); 

但看不到它，並要求我在繼承類實現的接口中創建setId()方法。

我也嘗試過這樣做

public long nextId() {
    setId(getIdCounter()+1);
    return id;
}

並用

arrayName.get(i).nextId();

但是它將無法正常工作，因為nextId不是靜態的，如果我將其設置為靜態，則還必須將id設置為靜態。

如何稱呼這個主對象或告訴我的對象更新其ID？

飛機類代碼

public class Aircraft {

    protected long  Id; 
    protected String name;
    protected Coordinates coordinates;
    private long idCounter;

    public long getId() {
        return Id;
    }
    public void setId(long id) {
        Id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Coordinates getCoordinates() {
        return coordinates;
    }
    public void setCoordinates(Coordinates coordinates) {
        this.coordinates = coordinates;
    }
    public long getIdCounter() {
        return idCounter;
    }
    public void setIdCounter(long idCounter) {
        this.idCounter = idCounter;
    }
    public Aircraft( String name, Coordinates coordinates) {

        this.name = name;
        this.coordinates = coordinates;
    }

    public long nextId() {
        setIdCounter(getIdCounter()+1);
        return idCounter;
    }
}

工廠級

public class ConcreteAircraftFactory extends AircraftFactory {

    public Flyable newAircraft (String type, String name, int longitude, int latitude, int height){

        Coordinates coord = Coordinates.makeCoordinate(longitude, latitude, height);

        if (type.equals("Baloon") || type.equals("baloon")) {
            return new Baloon(name, coord);
        }

        else if(type.equals("JetPlane") || type.equals("jetplane") || type.equals("Jetplane")) {
            return new JetPlane(name, coord);
        }

        else if(type.equals("Helicopter") || type.equals("helicopter")) {
            return new Helicopter(name, coord);
        }
        else
            return null;
    }
}

主要

ArrayList<Flyable> ar = new ArrayList<Flyable>();

for (int i = 1; i <FileReader.fileList.size(); i++) {
     ar.add(factory.newAircraft(FileReader.fileList.get(i)[0], FileReader.fileList.get(i)[1], Integer.parseInt(FileReader.fileList.get(i)[2]), 
            Integer.parseInt(FileReader.fileList.get(i)[3]), Integer.parseInt(FileReader.fileList.get(i)[4])));
}

繼承類之一（都具有相同的實現）

public class JetPlane extends Aircraft  implements Flyable{

private WeatherTower weatherTower;
private String text;

public JetPlane( String name, Coordinates coordinates) {
    super( name, coordinates);

}


public void updateConditions() {
    weatherTower= new WeatherTower();
    String newWeather = weatherTower.getWeather(coordinates);

    switch(newWeather) {

    case WeatherType.FOG:
        coordinates.setLatitude(coordinates.getLatitude()+1);
        text ="JetPlane #" + this.getName() + "(" + this.getId() + "): it's really foggy down there";
        try(PrintWriter out = new PrintWriter(new FileOutputStream("Simulation.txt", true))){
            out.println(text);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
    break;

    case WeatherType.RAIN:
        coordinates.setLatitude(coordinates.getLatitude()+5);
        text ="JetFighter #" + this.getName() + "(" + this.getId() + "): it's raining hard here";
        try(PrintWriter out = new PrintWriter(new FileOutputStream("Simulation.txt", true))){
            out.println(text);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
    break;

    case WeatherType.SUN:
        coordinates.setHeight(coordinates.getHeight()+2);
        coordinates.setLatitude(coordinates.getLatitude()+10);
        text ="JetFighter #" + this.getName() + "(" + this.getId() + "): flying in the sun is so much fun";
        try(PrintWriter out = new PrintWriter(new FileOutputStream("Simulation.txt", true))){
            out.println(text);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
    break;

    case WeatherType.SNOW:
        coordinates.setHeight(coordinates.getHeight()-7);
        text ="JetFighter #" + this.getName() + "(" + this.getId() + "): that thing about winter that guy from that tv show once said";
        try(PrintWriter out = new PrintWriter(new FileOutputStream("Simulation.txt", true))){
            out.println(text);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
    break;
    }

    if(coordinates.getHeight()<0) {
        coordinates.setHeight(0);
    }
    if(coordinates.getHeight()>100) {
        coordinates.setHeight(100);
    }
    if (coordinates.getHeight()==0) {
        weatherTower.unregister(this); //de vazut
        text ="Tower says: JetPlane #" + this.getName() + "(" + this.getId() + "): has been unrergistered";
        try(PrintWriter out = new PrintWriter(new FileOutputStream("Simulation.txt", true))){
            out.println(text);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
    }

}

public void registerTower(WeatherTower weatherTower) {
    weatherTower.register(this);
    text ="Tower says: JetPlane #" + this.getName() + "(" + this.getId() + "): has been rergistered";
    try(PrintWriter out = new PrintWriter(new FileOutputStream("Simulation.txt", true))){
        out.println(text);
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    }
    }

}

Answer 1

如果可以看到代碼，我可能會更有幫助，但是我認為，如果將此“ idCounter”設置為靜態變量，它將可以使用。

static long idCounter;