How to set auto trim on EntityManager?

[cash1981]

Hello.

Is there a way to set auto trim on the entityManager in components.xml or something like that?
Or maybe this is automatically done, I am not sure.

I would like to say entity.setValue(  hello ) to be persisted automatically as hello in the database.

[berat]

I am also interesting in this topic.
But I think it is not good to trim the value in data access tier.
This should be done by view/controller tier.
Maybe you can define an annotation your self such as @Trim for javabeans which will automatically trim string value
on getter methods.

[swd847]

You could add an Entity Listener in orm.xml that will accomplish this, you want it to listen to the pre-update and pre-persist events.

I would have this entity listener use component.getInstance to call out to a custom application scoped seam component. In this components create method you do something like this:

@Name("hibernateTrimmer")
@Scope(ScopeType.APPLICATION)
@AutoCreate
@Startup
public class HibernateTrimmer
{

    class Prop
    {
       Method getter, setter;
    }


    Map<Class, List<Prop>> propMap = new HashMap<Class, List<Prop>>();

    @In
    EntityManager entityManager;

    @Create
    public void findAnnotatedClasses() throws NoSuchMethodException
    {
     HibernateSessionProxy es = (HibernateSessionProxy) entityManager
          .getDelegate();
     Map<String, ClassMetadata> map = es.getSessionFactory()
          .getAllClassMetadata();
     for (String s : map.keySet())
     {

         ClassMetadata m = map.get(s);
         
         Class c = m.getMappedClass(EntityMode.POJO);

         //scan through the properties using m.getPropertyNames() and m.getPropertyType()
            //add all strink proiperties that you want to trim to the list
            //using reflection to get the appropriate setter and getter
         
     }
    }

    @BypassInterceptors
    public void doTrim(Object o) throws InvocationTargetException,
         IllegalAccessException
    {
     List<Prop> cls = propMap.get(o.getClass());
     if (cls == null)
     {
         return;
     }
     for (Prop m : cls)
     {
         
         String pb = m.getter.invoke(o);
            m.setter.invoke(o,pb.trim());
     }

    }
}

the code above is not complete, as I just ripped it out of a class of mine that does something similar (annotation based cache invalidation), but should give you the general idea.

[cash1981]

Hmm, if it is that difficult then I will just write trim() manually :-)

[stephen]

If the problem are blanks that users accidentally enter into form fields, then a JSF converter would be the cleanest solution.
Seam even makes this a little easier with an annotation:

@Converter(forClass = String.class) registers a seam component as default converter for all string valued properties.