Hi everyone!
Apparently there is no immediate interest in this subject, however this is a major issue for me since I have generic managed beans.
I’m willing to fix this myself but I need some pointers to where the type of the properties are evaluated.
Any help?
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.
From: Freire, Jose Luis (PT - Lisbon) [mailto:jfreire_at_deloitte.pt]
Sent: terça-feira, 9 de Junho de 2009 14:56
To: dev_at_javaserverfaces.dev.java.net
Subject: Is JSF incompatible with generics?
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.
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