Hi Koen,
I think this is a perfect issue to bring up on the new JSF 2.3 Expert
Group list, I have copied them.
Experts please weigh in and keep Koen on your responses.
Note I have removed dev_at_javaserverfaces.java.net to avoid cross posting.
Thanks!
Manfred
On 10/15/14, 9:08 AM, Koen Serneels wrote:
>
> Hi,
>
> When binding a JSF input text to a String property of a JSF
> ManagedBean, I want that an empty value is mapped to null and not ""
> (empty string).
>
> So, on tomcat7 (7.0.56) with JSF(2.2 RI) I can get this to work nicely
> by controlling the coercing behavior with the JVM property
> org.apache.el.parser.COERCE_TO_ZERO icw JSF
> javax.faces.INTERPRET_EMPTY_STRING_SUBMITTED_VALUES_AS_NULL as context
> param.
>
> When javax.faces.INTERPRET_EMPTY_STRING_SUBMITTED_VALUES_AS_NULL is
> set to true, JSF will set the local component value for the input
> component as null when the input if left empty.
>
> Next, when the value is actually set by tomcat's EL parser, it will
> NOT try to coerce the value when org.apache.el.parser.COERCE_TO_ZERO
> is set to false and the value remains null as I want (= OK)
>
> However (as I first posted this on the tomcat dev mailinglist) as of
> Tomcat8 and EL3 , a null value is coerced to "" (empty String) by the
> EL parser and the COERCE_TO_ZERO property has no longer any effect.
>
> This is as the specification now by default converts "" to null in
> case of a non-primitive number. But, in case of String, the specs says
> that a empty string ("") is not coerced to null and remains empty String.
>
> The relevant parts from the EL 3 spec:
>
> 1.23.2 Coerce A to String
>
> If A is null: return ""
>
> 1.23.3 Coerce A to Number type N
>
> If A is null and N is not a primitive type, return null.
>
> If A is null or "", return 0.
>
> My questions:
>
> -Wrt EL3, does the JSF param
> javax.faces.INTERPRET_EMPTY_STRING_SUBMITTED_VALUES_AS_NULL has any
> use left?
> Since the EL impl converts the null resulting from this property to
> empty String according to the spec
>
> -Is there a way that I can change this behavior in any way so that I
> can have null instead of empty String for empty text fields with
> Tomcat8/JSF2.2 RI?
>
> Thanks,
>
> Koen.
>