How to call an enum from another class?

Question

I am currently working on a grails project. I've created an enum located on a certain project folder, and wanted to access it from a class located on another project folder. My enum looks something like this:

public enum Options {  


OPTION_1("Option_1"),
OPTION_2("Option_2"),
OPTION_3("Option_3");

final String option;

Options(String option) {
    this.option = option;
}  

}

Now, I am having a problem in calling that enum from a certain class in my application. For example:

Response{
option = new Option.OPTION_1("Option_1") //not sure on how to call an enum
}

But what I wanted to do here is to assign the enum to the property option in the Response {} section..

How will I properly do that? Help please? Thanks.

Solution 1

Enums are predefined objects, it will have a private constructor, You can not create a new instance with new. You just need to call Option.OPTION_1;

Response{
option = Option.OPTION_1; 
}

Solution 2

You just need to reference it as Options.OPTION_1 there's no new on enums.

Option option = Options.OPTION_1;

Solution 3

You cannot instantiate an enum object, the only instances that are there are defined by you in the enum class.

So the correct way is:

Response {
    option = Options.OPTION_1;
}

Solution 4

You cannot create a new instance of an enum. There is no need to because it can hold only fixed number of values. So option = new Option.OPTION_1("Option_1") will do.

Solution 5

Not aware of the grails part in this, but your usage of enum seems to be incorrect

If you have an enum as

public enum Day {
    SUNDAY, MONDAY, TUESDAY, WEDNESDAY,
    THURSDAY, FRIDAY, SATURDAY 
}

You can access individual value using Day.MONDAY, Day.SUNDAY, etc.

Please check the java doc.

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Comments

[Jayan]

@ Rp- : your comment said not to use new. But the code had. I removed the 'new'. Hope that is fine.

[RP-]

Yeah.. Copied the code from OP's question, Thanks for the edit

[chemilleX3]

I think grails and java do same way in declaring enums, since grails is based in java..