Java中的Enum类中的简化方法 [英] Simplify method in an Enum class in Java

问题描述

我有一个包含Enum进行计算的类。
每个Enum使用外部类的一些或全部非静态变量。但是，由于它们无法访问实例变量，因此我必须将它们作为参数传递。

I have a class that contains an Enum to do calculation. Each Enum uses some or all of the non-static variables from the outer class. However since they can't access instance variable, I have to pass in them as parameters.

public class Outer{
    ClassA a;
    ClassB b;
    ClassC c;
    Map<MyEnum,Double> results= new EnumMap(MyEnum.class);
    private enum MyEnum{
        X{  public double calc(ClassA _a){ dostuff }           },
        Y{  public double calc(ClassB _b,ClassC _c){ dostuff } },
        Z{  public double calc(ClassA _a,ClassB _b){ dostuff } };
    }

    public void doCalc(){
        for(MyEnum item:MyEnum.values()){
            result.get(item) = item.calc(...);//Not uniform here
        }
    }
}

我的问题是我无法以统一的方式在for循环中传递参数。我可以让每个Enum方法都接受所有类，例如

My problem is that I can't have a uniform way to pass in the parameters in the for-loop. I could make each Enum method takes all classes like

public double calc(ClassA _a,ClassB _b,ClassC _c){ dostuff}

但是，如果我有更多的类，则该参数看起来很难看。

But if I have more classes, the parameter will look too ugly. Is there a better way to do this kind of thing?

推荐答案

为什么不将外部实例传递给 calc（）方法。在这种情况下，每个特定的枚举都有相应的逻辑来处理 Outer 对象，新的枚举不需要任何更改。

Why don't you pass the instance of outer to the calc() method. In that case, each specific enum will have the logic to deal with the Outer object accordingly and new enums wouldn't require any change.

class Outer {

    ClassA a;
    ClassB b;
    ClassC c;
    Map<MyEnum,Double> results= new EnumMap<MyEnum, Double>(MyEnum.class);
    private enum MyEnum{
        X{  public void calc(Outer o){ }           },
        Y{  public void calc(Outer o){  } },
        Z{  public void calc(Outer o){ } };
        abstract void calc(Outer o);
    }

    public void doCalc(){
        for(MyEnum item:MyEnum.values()){
            item.calc(this);
        }
    }
}


class ClassA {}
class ClassB {}
class ClassC {}

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