Question

I have a domain class with a bunch of non nullable strings. For one of the domain properties I call a custom validator which does a database check. When my original domain object has a field nulled in it, during the custom validate the domain object attempts to flush. This causing a ‘not-null property references a null or transient value’ error. I have my hibernate flush mode set to manual, so I have no idea why it is attempting to flush.

    String id
String name
String type
String description


static constraints =
{
    id unique: true, nullable:false
    type unique:false, nullable: false
    name(unique:['type'] nullable: false, blank:false,
        validator:{val, obj ->
            if(val != null)
            {
                    def result = OtherDomain.findByType(val)
                    if(result == null)
                    {
                        return 'foreignkey'
                    }

            }

        })


    description unique:false,nullable: false

}

static mapping =
{
    table 'track'
    id column:'id', type: 'string', generator: 'assigned'
    version false
}

There is no other domain modification going on. This is the only domain edited during this transaction.

Answer 1

Grails will normally flush the hibernate session before any query, so OtherDomain.findByType(val) is causing the flush. You can work around this by doing the query in a separate hibernate session like this:

OtherDomain.withNewSession { session ->
    def result = OtherDomain.findByType(val)
    if (result == null) {
        return 'foreignkey'
    }
}