使用 switch 语句在 Java 中出现问题解耦

Question

目前我正在制作一款小型游戏，在我的播放器中 class 我有很多重要的和依赖项。

所以我决定将 switch 语句单独分开 [=42=] 以便在方法中调用。

对于上下文播放器代码

import Accessories.BasicSight;
import Accessories.BasicSilencer;
import Accessories.BasicStock;
import Accessories.GoodSight;
import Accessories.GoodSilencer;
import Accessories.GoodStock;
import Accessories.GreatSight;
import Accessories.GreatSilencer;
import Accessories.GreatStock;
import PlayerState.AliveState;
import PlayerState.PlayerState;
import Guns.Weapon;
import Guns.*;

import java.util.Scanner;

public class PlayerSingleton {

    private static PlayerSingleton player;
    Scanner scanner = new Scanner(System.in);

    private String playerName;
    private int lives;
    private Integer health;
    public static Integer MAX_PLAYER_HEALTH = 500;
    public static Integer DEFAULT_PLAYER_LIVES = 2;

    private PlayerState playerState;

    private Weapon weapon;

    private PlayerSingleton(Weapon weapon, String pName) {
        this.weapon = weapon;
        this.playerName = pName;
        this.lives = DEFAULT_PLAYER_LIVES;
        setState(new AliveState(this));
    }

    public static PlayerSingleton getInstance(String choice, String name) {
        System.out.println("Choose Weapon to play the with: ");

        Weapon weapon = PlayerSingleton.chooseWeapon(choice);

        weapon.getDescription();

        if (player == null) {
            player = new PlayerSingleton(weapon, name);
        }
        return player;
    }

    public void sufferDamage(int damage) {
        playerState.takeDamage(damage);
    }

    public void respawn() {
        playerState.respawn();
    }

    public int getLives() {
        return lives;
    }

    public void setLives(int lives) {
        this.lives = DEFAULT_PLAYER_LIVES;
    }

    public int getHealth() {
        return health;
    }

    public void setHealth(Integer health) {
        this.health = health;
    }

    public void setState(PlayerState playerState) {
        this.playerState = playerState;
    }

    public void chosenWeapon() {
        System.out.println("Player Info: " + playerName + " " + "Has: " + health + " health and " + lives + " lives");
        System.out.println(weapon.getDescription() + ":" + " base damage: " + weapon.damage());
        
    }

    public static Weapon chooseWeapon(String choice) {
        switch (choice) {
            case "MP5":
                System.out.println("You have chosen MP5!");
                return new MP5Weapon();
            case "SNIPER":
                System.out.println("You have chosen Sniper!");
                return new SniperRifleWeapon();
            case "SHOTGUN":
                System.out.println("You have chosen Shotgun!");
                return new ShotgunWeapon();
            default:
                System.out.println("No gun by that name found!");
                return null;
        }
        
    }  
     public void addBasicAttachment(String attachment) {

        switch (attachment) {
            case "SIGHT":
                weapon = new BasicSight(weapon);
                break;
            case "SILENCER":
                weapon = new BasicSilencer(weapon);
                break;
            case "STOCK":
                weapon = new BasicStock(weapon);
                break;
            default:
                System.out.println("No Attachment found!");
        }
    }

    public void getBasicAttachment(String attachment) {

    }

    public void addGoodAttachment(String attachment) {
        switch (attachment) {
            case "SIGHT":
                weapon = new GoodSight(weapon);
                break;
            case "SILENCER":
                weapon = new GoodSilencer(weapon);
                break;
            case "STOCK":
                weapon = new GoodStock(weapon);
                break;
            default:
                System.out.println("No Attachment found!");
        }
    }

    public void addGreatAttachment(String attachment) {
        switch (attachment) {
            case "SIGHT":
                weapon = new GreatSight(weapon);
                break;
            case "SILENCER":
                weapon = new GreatSilencer(weapon);
                break;
            case "STOCK":
                weapon = new GreatStock(weapon);
                break;
            default:
                System.out.println("No Attachment found!");
        }
    }
    
}

所以上面的代码是我的玩家 class，我想把 addBasic/Good/Great 武器附件放在另一个单独的 class 文件中，以便更好地解耦代码。我不确定如何使用 switch 语句执行此操作。

关于如何处理这个问题有什么想法吗？

编辑：

正在从主函数调用开关方法：

import Accessories.*;
import Player.PlayerSingleton;
import Guns.Weapon;
import Guns.MP5Weapon;
import java.util.Scanner;

public class FireingRange {
Weapon weapon;
    public static void main(String[] args) {

        Scanner scanner = new Scanner(System.in);
        
        String name = scanner.nextLine();
      
        System.out.println(name + " to begin the game, first type a weapon you would like to play with:");
        System.out.println();
        System.out.println("Choose Weapon to play the with: ");
        System.out.println("'Shotgun' for Shotgun");
        System.out.println("'Sniper' for Sniper");
        System.out.println("'MP5' for MP5");
        String chooseWeapon = scanner.next().toUpperCase();

        PlayerSingleton player = PlayerSingleton.getInstance(chooseWeapon, name);
       
        System.out.println(player.getHealth());
        System.out.println(player.getLives());

       
        System.out.println();
      
        player.chosenWeapon();
        System.out.println("Are you ready to play the game?");

    }

抽象配件class:

import Guns.Weapon;

public abstract class AccessoryDecorator extends Weapon{
    public abstract String getDescription();
}

扩展 AccessoryDecorator 的附件：

public class BasicSight extends AccessoryDecorator {
    Weapon weapon;
    
    public BasicSight(Weapon weapon) {
        this.weapon = weapon;
    }
    @Override
    public String getDescription() {
        return weapon.getDescription() + ", Basic Sight";
    } 
    @Override
    public double weight() {
        return 7 + weapon.weight();
    }

    
    @Override
    public double damage() {
        return 7 + weapon.damage();
   }

所以 objective 是：

  public void addBasicAttachment(String attachment) {

        switch (attachment) {
            case "SIGHT":
                weapon = new BasicSight(weapon);
                break;
            case "SILENCER":
                weapon = new BasicSilencer(weapon);
                break;
            case "STOCK":
                weapon = new BasicStock(weapon);
                break;
            default:
                System.out.println("No Attachment found!");
        }
    }

    public void addGoodAttachment(String attachment) {
        switch (attachment) {
            case "SIGHT":
                weapon = new GoodSight(weapon);
                break;
            case "SILENCER":
                weapon = new GoodSilencer(weapon);
                break;
            case "STOCK":
                weapon = new GoodStock(weapon);
                break;
            default:
                System.out.println("No Attachment found!");
        }
    }
    public void addGreatAttachment(String attachment) {
        switch (attachment) {
            case "SIGHT":
                weapon = new GreatSight(weapon);
                break;
            case "SILENCER":
                weapon = new GreatSilencer(weapon);
                break;
            case "STOCK":
                weapon = new GreatStock(weapon);
                break;
            default:
                System.out.println("No Attachment found!");
        }
    }

在它自己的 class 中，然后能够用结果调用开关，然后将其添加到所选枪支的值中。

我似乎想不出如何 return 配件取决于创建的配件。

Answer 1

您可以制作一个具有某些功能的基础class，然后通过扩展的方式添加代码。另一种选择是制作一个实用程序 class，仅包含静态函数，您可以调用这些函数来操作传递的对象，如下所示：

public class PlayerUtil {
    public static void addGreatAttachment(PlayerSingleton player, String attachment) {
        Weapon weapon;
        switch (attachment) {
            case "SIGHT":
                weapon = new GreatSight(weapon);
                break;
            case "SILENCER":
                weapon = new GreatSilencer(weapon);
                break;
            case "STOCK":
                weapon = new GreatStock(weapon);
                break;
            default:
                System.out.println("No Attachment found!");
        }
        player.setWeapon(weapon);
    }
}

但对于您的情况，我建议您创建另一个 class：“EquipedWeapon”。这个 class 将有自己的 Weapon 字段，可能还有多个 Attachment 字段。您可以将更改附件的代码放在那里，甚至添加一些方法来获取带有附件的武器的统计信息，例如伤害或子弹扩散或 wtv，然后为武器内部创建一个 getter PlayerSingleton.

我还建议在您的游戏中创建一个 AttachmentManager class 来保存所有附件并允许您使用各种方法 select 它们。或者您可以使所有附件都扩展一个附件 class，该附件包含所有附件的静态列表。如果您将名称作为字段添加到附件 class 中，则可以创建一个静态方法来遍历所有附件并找到名称正确的附件 returns。或者使用静态 Hashmap.

Answer 2

您通常可以消除具有 class 继承的语言中的 switch 语句，例如 Java。特别是 Java 的灵活枚举。我碰巧有一个例子可以做到这一点：

import java.util.Arrays;
import java.util.Map;
import java.util.stream.Collectors;

public enum CommandEnum
{
    AUTHENTICATE("authenticate") {
        public Command newCommand(final String newMessageName) {
            return new Authenticate(newMessageName);
        }
    },

    ADD("add") {
        public Command newCommand(final String newMessageName) {
            return new Add(newMessageName);
        }
    },
    // ...bunch deleted for brevity    

    public final String messageName;

    // Collect all enumerations into a map you
    // can look up by name.    
    private static final Map<String, CommandEnum> messageNameMap =
        Arrays.stream(CommandEnum.values())
            .collect(
                Collectors.toMap(
                    commandEnum -> commandEnum.messageName,
                    commandEnum -> commandEnum
                )
            );


    CommandEnum(final String newMessageName) {
        messageName = newMessageName;
    }


    public abstract Command newCommand(final String newMessageName);

    public Command newCommand() {
        return newCommand(messageName);
    }


    public static CommandEnum getEnum(String messageName) {
        return messageNameMap.get(messageName);
    }
}

在这种情况下，您可以通过以下方式从字符串中获取枚举：

CommandEnum ce = CommandEnum.getEnum(...string...);

然后你把它转换成这样的命令：

if (null != ce) {
    Command c = ce.newCommand();
    ...
}

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