UserTypes should implement Serializable?

ljagged · **Joined:** Mon Nov 22, 2004 5:55 pm **Posts:** 5

I'm getting warnings in my log file to the effect of:

Code:

13:15:14,335  WARN CustomType:49 - custom type does not implement Serializable: class com.foo.bar.TimeIntervalUserType

My TimeInterval class implements Serializable but the TimeIntervalUserType does not. The code in net.sf.hibernate.type.CustomType seems to want the UserType to be Serializable:

Code:

    public CustomType(Class userTypeClass) throws MappingException {
        name = userTypeClass.getName();
        try {
            userType = (UserType)userTypeClass.newInstance();
        }
        catch(InstantiationException ie) {
            throw new MappingException("Cannot instantiate custom type: " + userTypeClass.getName());
        }
        catch(IllegalAccessException iae) {
            throw new MappingException("IllegalAccessException trying to instantiate custom type: " + userTypeClass.getName());
        }
        catch(ClassCastException cce) {
            throw new MappingException(userTypeClass.getName() + " must implement net.sf.hibernate.UserType");
        }
        types = userType.sqlTypes();
        if(!(java.io.Serializable.class).isAssignableFrom(userType.returnedClass())) {
            LogFactory.getLog(net.sf.hibernate.type.CustomType.class).warn("custom type does not implement Serializable: " + userTypeClass);
        }
    }

but the section in Hibernate In Action that describes UserType (Section 6.1.2) doesn't mention anything about custom user types having to be serializable. I'd appreciate it if someone could resolve the discrepency and maybe even explain why UserTypes need to be Serializable (if indeed they do).

Thanks,
Alex

christian · **Posted:** Tue Nov 23, 2004 3:26 pm

Just make it serializable, the error message couldn't be easier to understand.

christian · **Posted:** Tue Nov 23, 2004 3:31 pm

And this error message (as well as the code you have shown) means that the domain model class that is mapped _by_ the UserType has to implement Serializable. Yours doesn't, and from the exception, it looks like your UserType implementation is broken.

ljagged · **Joined:** Mon Nov 22, 2004 5:55 pm **Posts:** 5

Perhaps I was unclear.

My question is: which is correct -- the book or the code? The answer seems obvious, but not mentioning that custom mapping types need to be serializable seems to be a glaring omission and inconsistent with the careful detail evident in the rest of the book. I was hoping that you could confirm that UserType implementing classes also need to implement Serializable and perhaps briefly explain why.

Thanks,
Alex

ljagged · **Joined:** Mon Nov 22, 2004 5:55 pm **Posts:** 5

I'm sorry, you're right. I didn't read the code carefully and I see your point. Thanks for taking the time to reply.

Alex