Overview
The Code
For this example we have a simple Stateful bean called TelephoneBean as defined below. As a simple way of demonstrating the state we have to methods: speak and listen. You call speak and pass in some text, then you call listen to get your answer.
bean
business interface
EJB3 Notes
The bean class uses the annotation @Remote but does not specify a list of interfaces as is normally required. Per EJB3 rules, if the bean implements exactly one business interface it may use @Remote with no other values and that business interface is then implied to be a remote business interface. The same rule applies to identical usage of @Local.
The critical thing to know is that if you add another interface the rules change and require that you specify both interfaces in the @Remote annotation as in @Remote({Telephone.class, SecondInterface.class}).
Embedding
We're going to embed OpenEJB3 into a plain JUnit TestCase as a simple means of demonstrating the remote capabilities. We'll do the embedding in our test setUp method, then will make two test methods:
- one for invoking the bean's remote interface via the LocalInitialContextFactory which goes straight against the embedded container system
- one for invoking the bean's remote interface via the RemoteInitialContextFactory which connects to a Socket and communicates to the embedded container system over the ejbd protocol.
setUp
LocalInitialContextFactory: making in-vm calls to a remote business interface
RemoteInitialContextFactory: making networked calls to a remote business interface
This is the part you would want to do in apps that are running a different VM than the one in which the ejb container is embedded. These "client" VMs need only have the the openejb-client jar in their classpath and connect to OpenEJB via the RemoteInitialContextFactory like any other remote EJB client.