Hi

I have a class with an enum field persisted as STRING



I'm getting a Class Cast Exception when using this kind of query:



Exception:




Looking at the source code

the line String enumString = ( (Enum) value ).name();
I see the cast without a check to see if VALUE is a String

with normal queries (select a from A a), things go very well in respect to enums

Is this a bug or am I doing something wrong?

thanks in advance

Junico

Just more info

I changed EnumType to this:


it works...

but I still don't know if this is good or not

thanks in advance

Junico

Obviously value is a String (as annotated) and the rest is just unreachable code. So you just avoiding your Exception by not executing your else clause.

If you select single attributes, you will get them. Hibernate only replacing them with the enum type, if the whole entity is loaded.

Greetings Michael

Thanks for the answer Michael

If I understood your explanation, It is correct the enum value coming as a String, but even if I have a constructor like that



the exception still occurs.

In debug I don't know what is happening, but even my setter nor the constructor is called before the exception being thrown.

How can I execute this kind of query?

Thank You very much Michael

Junico

Hi, don't try to fetch the attirbutes by hand!

Normally hibernate uses the empty constructor and uses the setter/getter-methods or direct access (which you have chosen by your annotations on the attributes!) to the attributes to rebuild the object.

So your parametrized constructor and getter/setters won't be called at all.

A Query like this, should be enough:

Coded it by hand, so it may not be correct.
The result of this Query will be a list of Objects of the type you need. (Cast is required) Use where clause to limit the results. See Dokumentation for further details.


You don't have to use such an expression in your queries and it is not allowed. Should be rejected.

Use HQL or Criteria not SQL directly!

Greetings Michael

thank You urmech for your explanations!

I will show You why I am using this query:




As my app is i18n'd I need to show the products with the name in the current user Locale;

So what I do is



I need this new Product(....) because the NAME value will come from the ProductTranslated, not from the Product

Is this the right way to do that?

thanks in advance

Junico

Hi, how about declaring name @Transient and to resolve the current translation in your getter- or toString-Method ?

Same in your enum Color. (By the way @Transient isn't required there.)

Cause you can be sure that the string will be empty unless you have initialized it with the current language, so you have to do this only once.

If you want to change it, while your app is running and the products were already loaded, I would use the Observer/Observable-Pattern (see java.uitl).
So you can notify the products to update their describing. (Similar to Event-listeners)

By the way, you can do it by hand (not recommended). with your


But then you can't use Color as enum, you have to pass it as String and use
to resolve it. (Or use the valueOf-Method before you call the constructor, then you can keep your method signature unchanged.)

By the way, I wouldn't store the locale as attribute of PrroductXYZ.
It's a global variable, so place in an singleton class, so it is common to all objects. (If don't know what a singelton is, refer to "Effective Java" from Josuha Bloch.)

You surely don't want to display product1 in English and product 2 in German.

Greetings Michael