dev@javaserverfaces.java.net

Re: Is JSF incompatible with generics?

From: Mike Kienenberger <mkienenb_at_gmail.com>
Date: Tue, 9 Jun 2009 11:09:05 -0400

My guess is that it's not a bug.

Generics don't exist at run-time, only compile-time, so your
getters/setters would be of type java.lang.Object.

A "non-converted" value binding would be of String type since that's
what HTML forms submit by default.

I can't think of a way to make it work any better than manually
specifying a converter.

On Tue, Jun 9, 2009 at 10:53 AM, Freire, Jose Luis (PT -
Lisbon)<jfreire_at_deloitte.pt> wrote:
> Hi Manfred!
>
> Manually forcing the converter to "javax.faces.Integer" works.
>
> Did a little debugging and inspecting MethodBindingMethodExpressionAdapter.java, the methodExpression property has expectedType=String.class.
>
> It looks like generic based properties are incorrectly evaluated as String.
>
> Should I file a bug?
>
> José Freire
> Consulting - Financial Services Industry
> Deloitte Consultores, S.A.
> Deloitte | Edifício Atrium Saldanha, Praça Duque de Saldanha, 1 - 7º, 1050-094 Lisboa, Portugal
> Tel/Direct: +(351) 210 422 500 | Fax: +(351) 210 422 950
> jfreire_at_deloitte.pt | www.deloitte.pt
>
> Please consider the environment before printing.
>
>
>
> -----Original Message-----
> From: Manfred Riem [mailto:mriem_at_manorrock.org]
> Sent: terça-feira, 9 de Junho de 2009 15:16
> To: dev_at_javaserverfaces.dev.java.net
> Subject: RE: Is JSF incompatible with generics?
>
> Uhhh since when is the reference developer list deprecated? Note he
> is talking about the Mojarra implementation not anything from JBoss.
>
> I don't know exactly why it is not working, but having you
> tried registering the converter manually on the h:inputText?
>
> Manfred
>
>> -------- Original Message --------
>> Subject: Re: Is JSF incompatible with generics?
>> From: Ilya Shaikovsky <ishaikovsky_at_exadel.com>
>> Date: Tue, June 09, 2009 8:02 am
>> To: dev_at_javaserverfaces.dev.java.net
>>
>>
>> This list is deprecated. Use Jboss.org resources in order to get support.
>>
>> Regards!
>>
>> Freire, Jose Luis (PT - Lisbon) пишет:
>> >
>> > Using JSF 1.2.12, Facelets 1.1.14, Tomcat 6.0.18.
>> >
>> >
>> >
>> > I’m not sure where to open this bug, since I’m not sure if it’s JSF,
>> > Facelets, or EL related.
>> >
>> >
>> >
>> > If we have this simple class:
>> >
>> > *public* *class* GenericsTestController<E *extends* Object> {
>> >
>> >
>> >
>> >        *private* E value;
>> >
>> >
>> >
>> >        *public* E getValue() {
>> >
>> >               *return* value;
>> >
>> >        }
>> >
>> >
>> >
>> >        *public* *void* setValue(E value) {
>> >
>> >               *this*.value = value;
>> >
>> >        }
>> >
>> > }
>> >
>> >
>> >
>> > And we have this class to use as a managed bean (integerTest):
>> >
>> > *public* *class* IntegerTestController *extends*
>> > GenericsTestController<Integer> {
>> >
>> >
>> >
>> >        *public* String add() {
>> >
>> >               setValue(getValue()+1);
>> >
>> >               *return* *null*;
>> >
>> >        }
>> >
>> >        *public* String subtract() {
>> >
>> >               setValue(getValue()-1);
>> >
>> >               *return* *null*;
>> >
>> >        }
>> >
>> > }
>> >
>> >
>> >
>> > This JSF code will not work:
>> >
>> > <h:form>
>> >
>> >        Value:
>> >
>> >        <h:inputText value="#{integerTest.value}" />
>> >
>> >        <h:commandButton action="#{integerTest.add}" value="+" />
>> >
>> >        <h:commandButton action="#{integerTest.subtract}" value="-" />
>> >
>> > </h:form>
>> >
>> >
>> >
>> > With this error:
>> >
>> > _java.lang.ClassCastException_: java.lang.String cannot be cast to
>> > java.lang.Integer
>> >
>> >        at
>> > genericstest.IntegerTestController.add(_IntegerTestController.java:18_)
>> >
>> >        at sun.reflect.NativeMethodAccessorImpl.invoke0(_Native Method_)
>> >
>> >        at
>> > sun.reflect.NativeMethodAccessorImpl.invoke(_NativeMethodAccessorImpl.java:39_)
>> >
>> >        at
>> > sun.reflect.DelegatingMethodAccessorImpl.invoke(_DelegatingMethodAccessorImpl.java:25_)
>> >
>> >        at java.lang.reflect.Method.invoke(_Method.java:597_)
>> >
>> >        at org.apache.el.parser.AstValue.invoke(_AstValue.java:172_)
>> >
>> >        at
>> > org.apache.el.MethodExpressionImpl.invoke(_MethodExpressionImpl.java:276_)
>> >
>> >        at
>> > com.sun.facelets.el.TagMethodExpression.invoke(_TagMethodExpression.java:68_)
>> >
>> >        at
>> > javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(_MethodBindingMethodExpressionAdapter.java:88_)
>> >
>> >        at
>> > com.sun.faces.application.ActionListenerImpl.processAction(_ActionListenerImpl.java:102_)
>> >
>> >        at javax.faces.component.UICommand.broadcast(_UICommand.java:387_)
>> >
>> >        at
>> > javax.faces.component.UIViewRoot.broadcastEvents(_UIViewRoot.java:475_)
>> >
>> >        at
>> > javax.faces.component.UIViewRoot.processApplication(_UIViewRoot.java:756_)
>> >
>> >        at
>> > com.sun.faces.lifecycle.InvokeApplicationPhase.execute(_InvokeApplicationPhase.java:82_)
>> >
>> >        at com.sun.faces.lifecycle.Phase.doPhase(_Phase.java:100_)
>> >
>> >        at
>> > com.sun.faces.lifecycle.LifecycleImpl.execute(_LifecycleImpl.java:118_)
>> >
>> >        at javax.faces.webapp.FacesServlet.service(_FacesServlet.java:265_)
>> >
>> >        at
>> > org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(_ApplicationFilterChain.java:290_)
>> >
>> >        at
>> > org.apache.catalina.core.ApplicationFilterChain.doFilter(_ApplicationFilterChain.java:206_)
>> >
>> >        at
>> > org.apache.catalina.core.StandardWrapperValve.invoke(_StandardWrapperValve.java:233_)
>> >
>> >        at
>> > org.apache.catalina.core.StandardContextValve.invoke(_StandardContextValve.java:191_)
>> >
>> >        at
>> > org.apache.catalina.core.StandardHostValve.invoke(_StandardHostValve.java:128_)
>> >
>> >        at
>> > org.apache.catalina.valves.ErrorReportValve.invoke(_ErrorReportValve.java:102_)
>> >
>> >        at
>> > org.apache.catalina.core.StandardEngineValve.invoke(_StandardEngineValve.java:109_)
>> >
>> >        at
>> > org.apache.catalina.connector.CoyoteAdapter.service(_CoyoteAdapter.java:286_)
>> >
>> >        at
>> > org.apache.coyote.http11.Http11Processor.process(_Http11Processor.java:845_)
>> >
>> >        at
>> > org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(_Http11Protocol.java:583_)
>> >
>> >        at
>> > org.apache.tomcat.util.net.JIoEndpoint$Worker.run(_JIoEndpoint.java:447_)
>> >
>> >        at java.lang.Thread.run(_Thread.java:619_)
>> >
>> >
>> >
>> > In fact, it fails with the same error even if we override getValue and
>> > setValue on IntegerTestController.
>> >
>> >
>> >
>> > The only workaround is not to extend from GenericsTestController and
>> > implement the “value” property as Integer in the IntegerTestController.
>> >
>> >
>> >
>> > Help anyone?**
>> >
>> > * *
>> >
>> > *José Freire
>> > *Consulting - Financial Services Industry
>> > Deloitte Consultores, S.A.
>> > Deloitte | Edifício Atrium Saldanha, Praça Duque de Saldanha, 1 - 7º,
>> > 1050-094 Lisboa, Portugal
>> > Tel/Direct: +(351) 210 422 500 | Fax: +(351) 210 422 950
>> > jfreire_at_deloitte.pt | www.deloitte.pt
>> >
>> > Please consider the environment before printing.
>> >
>> >
>> >
>> >
>> >
>> > *Disclaimer:*
>> > Deloitte refers to one or more of Deloitte Touche Tohmatsu, a Swiss
>> > Verein, its member firms, and their respective subsidiaries and
>> > affiliates.  As a Swiss Verein (association), neither Deloitte Touche
>> > Tohmatsu nor any of its member firms has any liability for each
>> > other's acts or omissions.  Each of the member firms is a separate and
>> > independent legal entity operating under the names "Deloitte,"
>> > "Deloitte & Touche," "Deloitte Touche Tohmatsu," or other related
>> > names.  Services are provided by the member firms or their
>> > subsidiaries or affiliates and not by the Deloitte Touche Tohmatsu Verein.
>> > Privileged/Confidential Information may be contained in this message.
>> > If you are not the addressee indicated in this message (or responsible
>> > for delivery of the message to such person), you may not copy or
>> > deliver this message to anyone. In such case, you should destroy this
>> > message and kindly notify the sender by reply email. Please advise
>> > immediately if you or your employer do not consent to Internet email
>> > for messages of this kind. Opinions, conclusions and other information
>> > in this message that do not relate to the official business of my firm
>> > shall be understood as neither given nor endorsed by it.
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: dev-unsubscribe_at_javaserverfaces.dev.java.net
> For additional commands, e-mail: dev-help_at_javaserverfaces.dev.java.net
>
>