I do not succeed in passing EL expressions as attributes of a custom
component used in a tag file.
I could not find a clear doc on how to do that with EL 2.2.
My use case is the following :
1. a tag file taking attribute "context" as a parameter
2. inside the tag file, using a home made custom component taking
"bean" as a parameter
Context is an instance of an in-house class hierarchy. Bean is most
often in this case #{context.selected}.
If I use my tag file the following way in a top level f:view :
|<my:tag context="#{adminContext}"/>|
And inside my:tag definition :
|<my:custom bean="#{context.selected}"/>|
In my custom component, I have tried accessors like
|public ValueExpression getBean() {
return (ValueExpression) getStateHelper().eval(PropertyKeys.bean);
}
public void setBean(ValueExpression param) {
getStateHelper().put(PropertyKeys.bean, param);
}|
and attribute declaration of custom component in taglib like :
|<attribute>
<description>Nom du bean à afficher</description>
<name>bean</name>
<required>true</required>
<deferred-value>
<type>java.lang.Object</type>
</deferred-value>
</attribute>|
and attribute declaration of the tag file like :
|<attribute>
<name>context</name>
<deferred-value>
<type>java.lang.Object</type>
</deferred-value>
<required>true</required>
</attribute>|
I always get a "cast to ValueExpression exception" when calling getBean().
In a method of the custom component called by encodeBegin, I noticed
that I can access the attribute using getValueExpression("bean").
It returns an instance of ContextAwareTagValueExpressionUEL. Its
_wrapped attribute points to an instance of WrappedValueExpression,
encapsulating a ValueExpressionImpl whose value (expr) is
#{context.selected}. This instance of ValueExpressionImpl also has a
VariableMapper handling the translation of "context" to "adminContext".
Its expected type is javax.el.ValueExpression. This must cause my
exception...
How can I make it works ?
Thanks in advance.
I am using MyFaces 2.1.9, CODI 1.0.5, OpenWebBeans 1.1.6, Tomcat 7.0.32.
(question also asked on
http://stackoverflow.com/questions/15229708/el-expressions-as-custom-component-attributes
|
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