Java enum in Constructor

Question

i have a class person with a enum Gender and in the Person Constructor i want to initialize the gender and age. How can i instantiate a new Person in main() method?

class Person  {

   public enum Gender { M,F }

   int age;
   Gender gender;

   public Person(int age, Gender gender) {
       this.age=age; this.gender=gender;
   }           
}

public static void main(String[] args) {
    Person p = new Person(20, ?);        
}

Best Regards.

`Person p = new Person(20, Person.Gender.M);` just like any nested static class (which is what a nested enum is). — DontKnowMuchBut Getting Better, Apr 02 '18 at 20:59
ah thanks a lot, i have only tried Gender.M and other stuff. — , Apr 02 '18 at 21:01
Answer provided since someone just copied my comment word for word and presented it as an answer. Not cool. — DontKnowMuchBut Getting Better, Apr 02 '18 at 21:03
@DontKnowMuchButGettingBetter And completely permissible here on SO. You want to write an answer, write an answer. — chrylis -cautiouslyoptimistic-, Apr 02 '18 at 21:08
@chrylis: permissible maybe, but doesn't really pass the "smell test". At least he should have changed the wording a little bit, no? — DontKnowMuchBut Getting Better, Apr 02 '18 at 21:24

score 8 · Accepted Answer · answered Apr 02 '18 at 21:03

8

Use

Person p = new Person(20, Person.Gender.M);

Note that a nested enum is accessed like a nested static class.

answered Apr 02 '18 at 21:03

DontKnowMuchBut Getting Better

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score 2 · Answer 2 · answered Apr 02 '18 at 21:35

2

Person p = new Person(20, Person.Gender.M); works of course.

But it is clumsy enough to prefix the enum by the Person enclosing class at each time you need to specify an enum value.

So add the correct import in the client class. The IDE automatic imports feature should do it for you.

import Person.Gender;

and use a straighter way :

Person p = new Person(20, Gender.M);

answered Apr 02 '18 at 21:35

davidxxx

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Nice, 1+. You could also static import the Gender and then pass in M or F, useful if used a lot in the program. – DontKnowMuchBut Getting Better Apr 02 '18 at 21:38
2

@DontKnowMuchBut Getting Better Indeed ! Import features may make the code much more readable as used finely. – davidxxx Apr 02 '18 at 21:41

Java enum in Constructor

2 Answers2