EL getType obj.property1.sub_property

Question

I want to get the type of the sub property of the Object "obj", which is accessible as

obj.property1.sub_property

this code works only for direct property like obj.property

FacesContext.getCurrentInstance().getApplication().
     getELResolver().getType(FacesContext.getCurrentInstance().getELContext(),
     obj, "property1");

but how to make this work

FacesContext.getCurrentInstance().getApplication().
     getELResolver().getType(FacesContext.getCurrentInstance().getELContext(),
     obj, "property1.sub_property");

or How to get the TYPE of the complete expression #{obj.property1.sub_property}

Answer 1

this work only if obj.preperty1 is not null unless we have a null pointer exception

new ExpressionFactoryImpl().createValueExpression(
     FacesUtils.getFacesContext().getELContext(),
     expr, Object.class).getType(
     FacesUtils.getFacesContext().getELContext())

because as kolossus mention it will evaluate the first part, then the second...

Answer 2

That's the way ELResolver works. Even under the covers, each member is evaluated separately.

From the the specification:

The ELResolver concept is the heart of the unified EL...For example, in rendering the component behind the tag <h:outputText value=#{user.address.street}/>, the ELResolver is called three times. Once to resolve user, again to resolve the address property of user and finally,to resolve the street property of address

Translation: You need to evaluate property1 and subproperty separately. I'm typing this on a phone so I'll add a code sample later