How to declare Entities on the fly?

Question

I try to develop a Java Plugin application using the Java plugin framework. All plugins will have acces to a uniq database using JPA (with Eclipselink).

But each plugin will have there own Entities.

So I could not declare all Entities in one unique file persitence.xml in the core plugin.

The question is: is it possible to declare Entity class on the fly when declaring the EntityManagerFactory? I am already using a Map to get connection string and user/password from user configuration file.

Is there a way to do the same with Entities ?

Map<String, String> p = new HashMap<String, String>();
p.put("javax.persistence.jdbc.url", dns);
p.put("javax.persistence.jdbc.driver", "com.mysql.jdbc.Driver");
p.put("javax.persistence.jdbc.user", config.getProperty("com.cjrf.xbmo.db.username", ""));
p.put("javax.persistence.jdbc.password", config.getProperty("com.cjrf.xbmo.db.password", ""));
entityManagerFactory = Persistence.createEntityManagerFactory("mediamanager", p);

Thanks for your help.

Answer 1

If your only concern is not do declare the class files in the persistence.xml then you can use auto detect funcionality.

For eclipselink add this to persistence.xml

<exclude-unlisted-classes>false</exclude-unlisted-classes>

Now all annotation mapped with @Entity will be scanned automatically.

Answer 2

This might help:

http://www.dynamicjava.org/projects/dynamic-jpa