在使用枚举之前检查有效的枚举值 [英] Check valid enum values before using enum

问题描述

我试图查找一个枚举集，知道通常会有一个非匹配引发异常：我想在执行查找之前检查存在的值以避免异常。我的枚举看起来像这样：

  public enum Fruit {
 APPLE（apple），
 ORANGE（ 橙色）; 
; 
 private final String fruitname; 
水果（String fruitname）{
 this.fruitname = fruitname; 
} 
 public String fruitname（）{return fruitname;} 
} 
  

我想检查一下，在尝试使用相关枚举之前，是否说香蕉是我的枚举值之一。我可以通过将我的字符串与

  Compare.values（）[i] .fruitname 
  

但我想要像（pseduo-code）这样做：

  if（Fruit.values（）。contains（myStringHere））{... 
  

可以吗？我应该完全使用别的吗（Arrays？Maps？）？

编辑：最后我和NawaMan的建议一起走了，但感谢大家所有的帮助输入。

解决方案

我真的不知道一个内置的解决方案。所以你可能需要自己写一个静态方法。

  public enum Fruit {
 ... 
 static public boolean isMember（String aName）{
 Fruit [] aFruits = Fruit.values（）; 
（水果aFruit：aFruits）
 if（aFruit.fruitname.equals（aName））
返回true; 
返回false; 
} 
 ... 
} 
  

I'm trying to lookup against an Enum set, knowing that there will often be a non-match which throws an exception: I would like to check the value exists before performing the lookup to avoid the exceptions. My enum looks something like this:

public enum Fruit {
    APPLE("apple"),
    ORANGE("orange");
    ;
    private final String fruitname;
    Fruit(String fruitname) {
        this.fruitname = fruitname;
    }
    public String fruitname() {return fruitname;}
}

and I want to check if, say, "banana" is one of my enum values before attempting to use the relevant enum. I could iterate through the permissible values comparing my string to

Fruit.values()[i].fruitname

but I'd like to be able to do something like (pseduo-code):

if (Fruit.values().contains(myStringHere)) {...

Is that possible? Should I be using something else entirely (Arrays? Maps?)?

EDIT: in the end I've gone with NawaMan's suggestion, but thanks to everyone for all the helpful input.

解决方案

I really don't know a built-in solution. So you may have to write it yourself as a static method.

public enum Fruit {
   ...
   static public boolean isMember(String aName) {
       Fruit[] aFruits = Fruit.values();
       for (Fruit aFruit : aFruits)
           if (aFruit.fruitname.equals(aName))
               return true;
       return false;
   }
   ...
}

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