Setting ENUM value at runtime

Question

I have a ENUM defined as;

public enum YesNoEnum {
    Y,
    N
}

I am using this for one of my values voted.

So I use it within a loop (looping over object array from query response)

person.setVoted(responseArray[1] != null ? YesNoEnum.valueOf((String)responseArray[1]) : null);

I have the setter as

public void setVoted(YesNoEnum voted) {
    this.voted = voted;
}

Now I am getting an exception if the value for responseArray[1] is Y/N

If I debug/watch responseArray[1] , it shows type as YesNoEnum and shows value as "Y" It says

cannot cast an instance of YesNoEnum to an instance of String

So the code is while i am iterating using for(Object[] responseArray : response.getRecords()) — copenndthagen
– copenndthagen, Commented Nov 21, 2013 at 9:55
Never, ever, cast anything to String in Java, always use `toString()'. Casting is in general a bad idea in Java except when you have checked the type beforehand. — Neet
– Neet, Commented Nov 21, 2013 at 9:55

Maxim Shoustin · Accepted Answer · 2013-11-21 10:02:12Z

1

If I debug/watch responseArray[1] , it shows type as YesNoEnum and shows value as "Y" It says

If I understand right the responseArray is array of enum YesNoEnum.

Therefore you get error on casting enum instance to String:

(String)responseArray[1]

You can write just:

person.setVoted(responseArray[1]);

As a side note

to handle null I would change enum to:

public enum YesNoEnum {
    Y,
    N,
    UNKNOWN
}

and write:

person.setVoted(responseArray[1] != null ? responseArray[1] : YesNoEnum.UNKNOWN);

edited Nov 21, 2013 at 10:02

answered Nov 21, 2013 at 9:56

Maxim Shoustin

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1 Comment

Holger Over a year ago

If responseArray is of type Object[]as said in the question’s comments, a type cast is unavoidable. So it would be person.setVoted((YesNoEnum)responseArray[1]);

Neet · Accepted Answer · 2013-11-21 09:57:09Z

0

Use responseArray[1].toString() instead of (String)responseArray[1].

answered Nov 21, 2013 at 9:57

Neet

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3 Comments

Maxim Shoustin Over a year ago

YesNoEnum.valueOf(responseArray[1].toString()) = responseArray[1] right?

Neet Over a year ago

Look at the answer above, IMHO it's a much better solution.

Maxim Shoustin Over a year ago

well, in this case you dont need to ask if its null because you anyways provide null to method

Chris Knight · Accepted Answer · 2013-11-21 10:03:37Z

A YesNoEnum is not a String, it's an enum and you cannot cast from enum to String. You can either change the enum to a String by calling .toString(), or if you know that all objects in your array are of YesNoEnum types then you can skip the casting alltogether and do this:

person.setVoted(responseArray[1] != null ? responseArray[1] : null);

However, if the contents of responseArray are of a variety of types (some YesNoEnum, some String, some Object...), you will need to determine a way to transfrom each type into YesNoEnum objects, something better done in another method. As an aside, I highly recommend avoiding the use of mixed object types in your array. It creates all sorts of problems. Keep you arrays all of the same type. If you need to use mixed types, then take a differnt approach.

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