Java - 为类方法编写一个条件，确保只能使用 HashMap 的某些项目。

Question

好的，我有一个名为 WeaponList 的类，其中包含类型 <String, Ranged> 的静态 HashMap (Ranged 是另一个类)Ranged 类还扩展了另一个称为 Weapon 的类。

然后我还有另一个类叫做 Scout。侦察兵是武器(记得是远程扩展)和点的组合。我还应该指出，ScoutSquad 类是 Scout 的聚合，具有 get 和 set 方法。

所以在主程序中，当你实例化一个侦察兵对象时，每个侦察兵的默认远程武器是“ bolt 手枪”，默认点数是13。

现在，在 Scout 类中，有一个选项可以通过 rangedUpgrade(Ranged ranged) 方法升级你的远程武器。所以在主程序中使用这行代码:scouts.getScout(5).rangedUpgrade(WeaponList.getRanged("Shotgun"));成功升级索引 5 处的侦察兵，并显示新武器和侦察兵新点数(因为每个武器都有与其关联的点数)

但是目前侦察兵可以升级到 WeaponList 类 HashMap 中的任何远程武器。我希望侦察兵只能升级到 HashMap 中的某些远程武器。我已经尝试使用 if 语句设置条件，但到目前为止没有成功。 (Scout 类第 27 - 35 行)

我将提供所有相关类的代码，并希望有人可以提供帮助。

谢谢。

武器列表类

package armoury1;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import troops.scouts.Scout;

public class WeaponList
{
    static Map<String, Ranged> rangedlist = new HashMap<String, Ranged>()
    {{          
        put("Bolter", new Ranged2H("Bolter", 1));
        put("Bolt Pistol", new Ranged("Bolt Pistol", 1));
        put("Flamer", new Ranged2H("Flamer", 1));
        put("Meltagun", new Ranged2H("Meltagun", 1));
        put("Plasma Gun", new Ranged2H("Plasma Gun", 1));
        put("Plasma Pistol", new Ranged("Plasma Pistol", 10));
        put("Shotgun", new Ranged2H("Shotgun", 10));
        put("Sniper Rifle", new Ranged2H("Sniper Rifle", 5));

        put("Assault Cannon", new Ranged2H("Assault Cannon", 10));
        put("Cyclone Missle Launcher", new Ranged2H("Cyclone Missle Launcher", 10));
        put("Heavy Bolter", new Ranged2H("Heavy Bolter", 10));
        put("Heavy Flamer", new Ranged2H("Heavy Flamer", 10));
        put("Assault Cannon", new Ranged2H("Lascannon", 10));
        put("Missle Launcher", new Ranged2H("Missle Launcher", 10));
        put("Multi Melta", new Ranged2H("Multi Melta", 10));
        put("Plasma Cannon", new Ranged2H("Plasma Cannon", 10));

    }};

    public static Ranged getRanged(String index)
    {       
        return rangedlist.get(index);   
    }

    public static Map<String, Ranged> getRangedList()
    {           
        return rangedlist;
    }
}

侦察类

package troops.scouts;

import armoury.Wargear;
import armoury1.Melee;
import armoury1.Ranged;
import armoury1.Weapon;
import armoury1.WeaponList;

public class Scout
{
    private Weapon ranged, melee;
    private int points;

    //DEFAULT SCOUT
    public Scout() 
    {       
        ranged = new Ranged("Bolt Pistol", 0);
        melee = new Melee("Close Combat Weapon", 0);

        points = 13; 
        points = points + ranged.getWeaponPoints() + melee.getWeaponPoints();

    }

    public void rangedUpgrade(Ranged ranged)
    {       
        if (ranged.equals(WeaponList.getRanged("Shotgun")));
        {       
            this.ranged = ranged; 
            points = points + ranged.getWeaponPoints();
        }   


        else 
            System.out.println("Can not have this weapon");
    }   

    public void meleeUpgrade(Melee melee) 
    {
        this.melee = melee; 
        points = points + melee.getWeaponPoints();
    }

    public Weapon getRangedUpgrade()
    {
        return ranged;
    }

    public Weapon getMeleeUpgrade()
    {
        return melee;
    }

    @Override
    public String toString()
    {
        return "|| " + "Ranged Weapon: " + ranged + " || " + "Melee Weapon: " + melee + " || " + "Points: " + points;
    }
}

主程序

package main;

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
import armoury1.Melee;
import armoury1.Ranged;
import armoury1.Weapon;
import armoury1.WeaponList;
import troops.scouts.Scout;
import troops.scouts.ScoutSergeant;
import troops.scouts.ScoutSquad;

public class ArmyBuilderDemo
{
    public static void main(String[] args) throws Exception
    {       
        ScoutSquad scouts = new ScoutSquad("Squad 1");
        Scanner input = new Scanner(System.in);

        System.out.println("Enter the squad size: ");
        int size = input.nextInt();

        for (int i = 0; i < size; i++)
            scouts.addScout(new Scout());

        System.out.println(scouts.getScoutSquad());

        scouts.getScout(5).rangedUpgrade(WeaponList.getRanged("Shotgun"));
        scouts.getScout(5).meleeUpgrade(WeaponList.getMelee(3));

        System.out.println(scouts.getScoutSquad());

      input.close();
    }   
}

远程类别(扩展武器)

package armoury1;

import java.util.ArrayList;
import java.util.List;

import troops.scouts.Scout;

public class Ranged extends Weapon 
{       
    public Ranged(String name, int points) 
    {       
        super(name, points);
    }   
}

Answer 1

请在 Ranged 类中实现 .equals() 方法。

此外，您在 rangedUpgrade(Ranged ranged) 中放置的 if 条件在同一行终止。

请将该方法的代码修改为:

public void rangedUpgrade(Ranged ranged) {       
        if (ranged.equals(WeaponList.getRanged("Shotgun"))){       
            this.ranged = ranged; 
            points = points + ranged.getWeaponPoints();
        } else 
            System.out.println("Can not have this weapon");
        }  
}