Hi,
Without it, the BV's @NotNull wouldn't have any use anymore in JSF and
models would keep getting polluted with empty strings (which has quite
different semantics as compared to null), so I don't see why it should be
phased out.
I'd rather alter JSF impl's own EL resolver to do the desired job based on
INTERPRET_EMPTY_STRING_SUBMITTED_VALUES_AS_NULL during update model values
phase.
On the other hand, if we make
INTERPRET_EMPTY_STRING_SUBMITTED_VALUES_AS_NULL=true
the default setting, then we could perhaps indeed phase it out.
Cheers, B
On Thu, Oct 16, 2014 at 5:36 PM, manfred riem <manfred.riem_at_oracle.com>
wrote:
> Hi Bauke,
>
> Is that the only use case that would still require this setting?
>
> If so could we phase this setting out in 2.3 and tell people that would
> need this to register their own EL resolver and make sure that the JSF
> runtime always uses EL coercion to determine the actual value?
>
> What do you think?
>
> Manfred
>
>
> On 10/15/14, 10:37 AM, Bauke Scholtz wrote:
>
> Hi,
>
> The INTERPRET_EMPTY_STRING_SUBMITTED_VALUES_AS_NULL has still any use.
> Without it, BV's @NotNull wouldn't have any effect.
>
> The problem here is that COERCE_TO_ZERO has in Tomcat been changed to
> not be applied on java.lang.String anymore. See Tomcat 8 source:
> http://grepcode.com/file/repo1.maven.org/maven2/org.apache.tomcat/tomcat-jasper-el/8.0.11/org/apache/el/lang/ELSupport.java#ELSupport.coerceToType%28java.lang.Object%2Cjava.lang.Class%29
> Compare it to Tomcat 7 source where it get applied on everything, including
> String:
> http://grepcode.com/file/repo1.maven.org/maven2/org.apache.tomcat/tomcat-jasper-el/7.0.55/org/apache/el/parser/AstValue.java#AstValue.setValue%28org.apache.el.lang.EvaluationContext%2Cjava.lang.Object%29
>
> This change is indeed a major drawback. I tried to reproduce this on
> WildFly 8.1.0 which uses com.sun EL impl. It unfortunately also pollutes
> the model with empty strings during update model values phase after
> EL-coercing the null submitted value to empty string. I see one possible
> theoretical trick: fool the EL ValueExpression by telling that we want to
> resolve it as java.lang.Object instead of java.lang.String.
>
> Cheers, Bauke
>
>
>
> On Wed, Oct 15, 2014 at 5:23 PM, manfred riem <manfred.riem_at_oracle.com>
> wrote:
>
>> 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.
>>
>>
>>
>>
>