Author: rmannibucau
Date: Sun Oct 16 20:46:43 2011
New Revision: 1184925
URL: http://svn.apache.org/viewvc?rev=1184925&view=rev
Log:
updating dynamic datasource example markdown
Modified:
openejb/trunk/openejb/examples/dynamic-datasource-routing/README.md
Modified: openejb/trunk/openejb/examples/dynamic-datasource-routing/README.md
URL:
http://svn.apache.org/viewvc/openejb/trunk/openejb/examples/dynamic-datasource-routing/README.md?rev=1184925&r1=1184924&r2=1184925&view=diff
==============================================================================
--- openejb/trunk/openejb/examples/dynamic-datasource-routing/README.md
(original)
+++ openejb/trunk/openejb/examples/dynamic-datasource-routing/README.md Sun Oct
16 20:46:43 2011
@@ -5,7 +5,23 @@
The openejb dynamic datasource api aims to allow to use multiple data sources
as one from an application point of view.
It can be useful for technical reasons (load balancing for example) or more
generally
-functionnal reasons (filtering, aggregation, enriching...).
+functionnal reasons (filtering, aggregation, enriching...). However please
note you can choose
+only one datasource by transaction. It means the goal of this feature is not
to switch more than
+once of datasource in a transaction. The following code will not work:
+
+ @Stateless
+ public class MyEJB {
+ @Resource private MyRouter router;
+ @PersistenceContext private EntityManager em;
+
+ public void workWithDataSources() {
+ router.setDataSource("ds1");
+ em.persist(new MyEntity());
+
+ router.setDataSource("ds2"); // same transaction -> this
invocation doesn't work
+ em.persist(new MyEntity());
+ }
+ }
In this example the implementation simply use a datasource from its name and
needs to be set before using any JPA
operation in the transaction (to keep the logic simple in the example).
