分手長切換

Question

我有這樣的代碼：

public void addSkillXp(SkillType attribute, int value) { 
    final SkillDatabaseEntity skillDatabaseEntity = skillValueCache.getEntity(); 

    switch (attribute) { 
     case TWO_HANDED_CRUSHING_WEAPONS: 
      skillDatabaseEntity.setTwoHandedCrushingWeaponsXp(value); 

      skillMapper.addTwoHandedCrushingWeaponsXp(userEntity.getId(), value); 
      break; 
     case ONE_HANDED_CRUSHING_WEAPONS: 
      skillDatabaseEntity.setOneHandedCrushingWeaponsXp(value); 

      skillMapper.addOneHandedCrushingWeaponsXp(userEntity.getId(), value); 
      break; 
     case TWO_HANDED_AXES: 
      skillDatabaseEntity.setTwoHandedAxesXp(value); 

      skillMapper.addTwoHandedAxesXp(userEntity.getId(), value); 
      break; 
     case ONE_HANDED_AXES: 
      skillDatabaseEntity.setOneHandedAxesXp(value); 

      skillMapper.addOneHandedAxesXp(userEntity.getId(), value); 
      break; 
     case THROWING_WEAPONS: 
      skillDatabaseEntity.setThrowingWeaponsXp(value); 

      skillMapper.addThrowingWeaponsXp(userEntity.getId(), value); 
      break; 
     case FISTFIGHT: 
      skillDatabaseEntity.setFistfightXp(value); 

      skillMapper.addFistfightXp(userEntity.getId(), value); 
      break; 
     ... 
} 

的開關推移更多的20例該SkillDatabaseEntity是一個簡單的DAO類：

public class SkillDatabaseEntity { 

    private int twoHandedCrushingWeaponsXp; 
    private int oneHandedCrushingWeaponsXp; 
    private int twoHandedAxesXp; 
    private int oneHandedAxesXp; 
    private int throwingWeaponsXp; 
    private int fistfightXp; 
    private int longswordsXp; 
    private int shortswordsXp; 
    private int polearmsXp; 
    private int daggersXp; 
    private int longbowsXp; 
    private int showrtbowsXp; 
    private int crossbowsXp; 
    private int lightArmorXp; 
    private int heavyArmorXp; 
    private int robeArmorXp; 
    private int armorlessDefenseXp; 
    private int shieldDefenseXp; 
    private int staffsXp; 
    private int wandsXp; 
    private int spectresXp; 
    private int scavengingXp; 
    private int cookingXp; 

    public int getTwoHandedCrushingWeaponsXp() { 
     return twoHandedCrushingWeaponsXp; 
    } 

    public void setTwoHandedCrushingWeaponsXp(int twoHandedCrushingWeaponsXp) { 
     this.twoHandedCrushingWeaponsXp = twoHandedCrushingWeaponsXp; 
    } 

    public int getOneHandedCrushingWeaponsXp() { 
     return oneHandedCrushingWeaponsXp; 
    } 

    public void setOneHandedCrushingWeaponsXp(int oneHandedCrushingWeaponsXp) { 
     this.oneHandedCrushingWeaponsXp = oneHandedCrushingWeaponsXp; 
    } 

    public int getTwoHandedAxesXp() { 
     return twoHandedAxesXp; 
    } 

    public void setTwoHandedAxesXp(int twoHandedAxesXp) { 
     this.twoHandedAxesXp = twoHandedAxesXp; 
    } 

    public int getOneHandedAxesXp() { 
     return oneHandedAxesXp; 
    } 

    public void setOneHandedAxesXp(int oneHandedAxesXp) { 
     this.oneHandedAxesXp = oneHandedAxesXp; 
    } 

    public int getThrowingWeaponsXp() { 
     return throwingWeaponsXp; 
    } 

    public void setThrowingWeaponsXp(int throwingWeaponsXp) { 
     this.throwingWeaponsXp = throwingWeaponsXp; 
    } 
    ... 
} 

我需要添加removeSkillXp但真正要避免這種巨大的交換機並且如果我在這裏我想提高老scwitch了。我怎樣才能做到這一點？

我有什麼作爲計劃是創建這樣一個新的類：

SkillModifier：

• increaseExperience（UserEntity，值）
• decreaseExperience（UserEntity，值）
• getExperience （UserEntity，value）
• getSupportedSkillType（）

而創建這個類在開關任何情況下的一個實例，添加實例到地圖（可以使用Spring DI輕鬆完成），並使用這樣的：

public void addSkillXp(SkillType attribute, int value) { 
    skillMap.get(attribute).increaseExperience(userEntity, value); 
} 

能否這項工作？還是有更好的模式？

Answer 1

整個開關似乎是多餘的，因爲每個案件都做同樣的事情。爲什麼不創建一個抽象類武器，它有一個方法增加XP並且由每個武器類擴展（2h等）。
通過這種方式，實現在抽象類中，其他子類只需調用.increaseXP。

順便說一句，數據庫類似乎是不必要的，只是爲每個玩家保留一個武器列表/數組。

一些更多的背景信息，請參閱：

https://sourcemaking.com/refactoring/replace-conditional-with-polymorphism

Answer 2

如果從移動代碼的功能到對象，事情就變得容易多了。

例如：

enum SkillType { 
    TWO_HANDED_CRUSHING_WEAPONS { 
     @Override 
     void updateEntity(SkillDatabaseEntity entity, int value) { 
      entity.setTwoHandedCrushingWeaponsXp(value); 
     } 

     @Override 
     void mapSkill(SkillMapper mapper, int userId, int value) { 
      mapper.addTwoHandedCrushingWeaponsXp(userId, value); 

     } 
    }, 
    ONE_HANDED_CRUSHING_WEAPONS { 
     @Override 
     void updateEntity(SkillDatabaseEntity entity, int value) { 
      entity.addOneHandedCrushingWeaponsXp(value); 
     } 

     @Override 
     void mapSkill(SkillMapper mapper, int userId, int value) { 
      mapper.addOneHandedCrushingWeaponsXp(userId, value); 

     } 
    }, 
    TWO_HANDED_AXES { 
     @Override 
     void updateEntity(SkillDatabaseEntity entity, int value) { 
      entity.setTwoHandedAxesXp(value); 
     } 
     @Override 
     void mapSkill(SkillMapper mapper, int userId, int value) { 
      mapper.addTwoHandedAxesXp(userId, value); 

     } 
    }; 

    abstract void updateEntity(SkillDatabaseEntity entity, int value); 

    abstract void mapSkill(SkillMapper mapper, int userId, int value); 
} 

public void addSkillXp(SkillType skill, int value) { 
    final SkillDatabaseEntity skillDatabaseEntity = skillValueCache.getEntity(); 
    skill.updateEntity(skillDatabaseEntity, value); 
    skill.mapSkill(skillMapper, userEntity.getId(), value); 
} 

這裏addSkillXp已經變成了三行代碼。

另一個優雅的好處是，所有的技能代碼都在同一個enum。