Passing DataSources to EclipseLink JPA

When you hear the same question twice it's time to blog the answer so the third time it comes up you can point to the blog. ;-) This time it's whether you can pass a DataSource to EclipseLink JPA and have it use that instead of what's configured in persistence.xml (or perhaps not configured in persistence.xml).

Yes, you can pass a DataSource. Here's a code sample that illustrates creating a Derby DataSource and passing it as a property to createEntityManagerFactory. Works like a charm.

--Shaun

private DataSource createDataSource() {
   ClientDataSource dataSource = new ClientDataSource();
   dataSource.setServerName("localhost");
   dataSource.setPortNumber(1527);
   dataSource.setDatabaseName("sample");
   dataSource.setUser("app");
   dataSource.setPassword("app");
   return dataSource;
}

private EntityManagerFactory getEntityManagerFactory() {
   if (emf == null) {
      Map properties = new HashMap();
      properties
         .put(PersistenceUnitProperties.NON_JTA_DATASOURCE,createDataSource());
      emf = Persistence.createEntityManagerFactory(PU_NAME, properties);
   }
   return emf;
}