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How to use enums?

开发者 https://www.devze.com 2023-02-09 06:19 出处:网络
I\'m not sure how to use enum in Java. Am I using it right in the following example? enum Sex {M, F}; public class person{

I'm not sure how to use enum in Java. Am I using it right in the following example?

enum Sex {M, F};

public class person{  
    private person mom;  
    private Sex sex;

    public person(Sex sex){  
        this.sex = sex;  
        //is this how i'd set sex?  
    }  

    public void setMom(person mom){  
        if(mom.sex == 'M'){}  
        //is this how i would check to see if the sex of the passed person a开发者_高级运维rgument is male?  
   }  
}


This is what you want to use:

 if(mom.sex == Sex.M)

however, I would definitely spell out the enum constants as MALE and FEMALE.


In your case you should simply write:

public void setMom(person mom){  
    if(mom.sex == Sex.M){}  
    //is this how i would check to see if the sex of the passed person argument is male?  

}

Please note that enums allow you to check equality with ==

You can have a look to http://download.oracle.com/javase/tutorial/java/javaOO/enum.html for more information.


There is third possibility you might not have considered is null. e.g. mom.sex could be MALE, FEMALE or null

If you what to validate I would write it as

if(mom.sex != Sex.FEMALE) // not the only valid option.

As an enum type may get more options over time, this is best practice IMHO.

A Person should have a mom when created/born. I would add this to the constructor and possibly not allow it to be changed. i.e. make the mom and/or sex final and drop the setter.

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