Casts in JPQL with EclipseLink

Is it possible to use casts in JPQL? In HQL it seems to be supported

cast(... as ...), where the second argument is the name of a Hibernate type, and extract(... from ...) if ANSI cast() and extract() is supported by the underlying database

source : Hibernate reference

My target JPA provider is EclipseLink, so any EclipseLink specific s开发者_运维问答olution is ok as well.

According to the specification of JPA/JPA2, JPQL is not supporting query casts. However, the most recent EclipseLink Release 2.1.0 does have a propritary support for downcasts in JPQL and expressions, please look here

Literal downcasts in EclipseLink JPQL are currently not supported, but might be if the following issue gets resolved : https://bugs.eclipse.org/bugs/show_bug.cgi?id=315087

It should be supported using JPA 2.1 TREAT operator.