Grails "don't flush the Session after an exception occurs" error message - grails

Question

I see that this error message has been posted several times already in the context of hibernate.
I am getting this error while using grails service and a domain class, any help will be really appreciated
Domain class
class Coupon {
Date dateCreated
Date lastUpdated
String code
String email
String address
String state
String city
String zip
def couponCodeGeneratorService
def beforeValidate() {
println code+"---------8-"
code = couponCodeGeneratorService.generate()
println code+"----------"
}
static constraints = {
email blank:false,email:true
address blank:false
state blank:false
city blank:false
zip blank:false
}
}
Service
class CouponCodeGeneratorService {
Random randomGenerator = new Random()
def serviceMethod() {
}
def generate(){
def group1 = randomGenerator.nextInt(9999)+"";
def group2 = randomGenerator.nextInt(9999)+"";
def group3 = randomGenerator.nextInt(9999)+"";
def group4 = randomGenerator.nextInt(9999)+"";
return group1.padLeft(4,"0") +group2.padLeft(4,"0")+group3.padLeft(4,"0")+group4.padLeft(4,"0")
}
}
The error I am getting is
---------8-
4844634041715590----------
4844634041715590---------8-
| Error 2012-09-10 11:32:54,938 [http-bio-8080-exec-7] ERROR hibernate.AssertionFailure - an assertion failure occured (this may indicate a bug in Hibernate, but is more likely due to unsafe use of the session)
Message: null id in com.easytha.Coupon entry (don't flush the Session after an exception occurs)
Line | Method
->> 19 | beforeValidate in com.easytha.Coupon
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
| 46 | onApplicationEvent in org.grails.datastore.mapping.engine.event.AbstractPersistenceEventListener
| 24 | save . . . . . . . in com.easytha.CouponController
| 186 | doFilter in grails.plugin.cache.web.filter.PageFragmentCachingFilter
| 63 | doFilter . . . . . in grails.plugin.cache.web.filter.AbstractFilter
| 886 | runTask in java.util.concurrent.ThreadPoolExecutor$Worker
| 908 | run . . . . . . . in ''
^ 662 | run in java.lang.Thread
| Error 2012-09-10 11:32:54,944 [http-bio-8080-exec-7] ERROR errors.GrailsExceptionResolver - AssertionFailure occurred when processing request: [POST] /EasyTha/coupon/save - parameters:
zip: asdf
address: asd
email: s.s#s.xom
state: asd
code:
create: Create
city: asdf
null id in com.easytha.Coupon entry (don't flush the Session after an exception occurs). Stacktrace follows:
Message: null id in com.easytha.Coupon entry (don't flush the Session after an exception occurs)
Line | Method
->> 19 | beforeValidate in com.easytha.Coupon
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
| 46 | onApplicationEvent in org.grails.datastore.mapping.engine.event.AbstractPersistenceEventListener
| 24 | save . . . . . . . in com.easytha.CouponController
| 186 | doFilter in grails.plugin.cache.web.filter.PageFragmentCachingFilter
| 63 | doFilter . . . . . in grails.plugin.cache.web.filter.AbstractFilter
| 886 | runTask in java.util.concurrent.ThreadPoolExecutor$Worker
| 908 | run . . . . . . . in ''
^ 662 | run in java.lang.Thread
I am not very familiar with Hibernate, also is this a correct way to create a coupon code that looks like a credit card number?

Answer 1

I suspect the problem may be that the CouponCodeGeneratorService is transactional. Therefore, when you call the service method from inside your beforeValidate you're opening and closing a transaction (even though you don't touch the database inside the method), which among other things will cause another flush of the session.
Try making the service non-transactional:
static transactional = false