Re: [eclipselink-users] How to use the criteria api metamodel in a java

["Michael O'Brien" <michael.obrien@xxxxxxxxxx>]

Gabriele,
   Yes, the Criteria and Metamodel API's are part of JPA 2.0 which is 
part of JEE6.  JPA 1.0/2.0 has always supported SE persistence via the 
javax.persistence specification package import.
   Your code on the stackoverflow post looks fine, you do not require 
canonical generated classes as your EntityType<Meaning> dynamic 
metamodel Type class is ok to use.

   A Java SE test model is in SVN below.
http://fisheye2.atlassian.com/browse/eclipselink/trunk/jpa/eclipselink.jpa.test/src/org/eclipse/persistence/testing/models/jpa/metamodel

   The Java SE metamodel (dynamic in-memory non-canonical) test cases 
are below.
http://fisheye2.atlassian.com/browse/eclipselink/trunk/jpa/eclipselink.jpa.test/src/org/eclipse/persistence/testing/models/jpa/metamodel

   For persistence.xml you do not need to use the JPA 2.0 schema unless 
you require use of new elements/attributes introduced in 2.0 - there are 
none for Criteria/Metamodel except for canonical generation (if you 
require it).  The "em.getMetamodel()" call does not require static 
generated classes - it will generate them in-memory as your Meaning_ 
variable.
http://wiki.eclipse.org/UserGuide/JPA/Using_the_Canonical_Model_Generator_(ELUG)#EclipseLink_custom_processor_options

   Either of these headers will work in persistence.xml - use the 2.0 
one if you use one of the 5 canonical metamodel properties introduced in 2.0

<!-- persistence version="2.0" 
xmlns="http://java.sun.com/xml/ns/persistence"; 
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"; 
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence 
http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd"-->
<persistence version="1.0" 
xmlns="http://java.sun.com/xml/ns/persistence"; 
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"; 
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence 
http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd";>

   For usage, there are 3 ways to use the Metamodel API detailed below 
(Static - via canonical modelgen generated "_" classes, dynamic in 
memory typesafe and dynamic in memory non-typesafe (using String get 
methods)
http://wiki.eclipse.org/EclipseLink/Development/JPA_2.0/metamodel_api#API_Usage

   I do not see anything JPA 2.0 related in your Entity.
   If you are seeing compile-time or run-time errors running this query 
- you may post the stacktrace and logs if you would like.
   thank you
   /michael


Gabriele Kahlout wrote:
> http://stackoverflow.com/questions/3458742/why-the-compiler-doesnt-recognize-the-metamodel-attributes
>