Can I reuse a session bean with another injected classes?

Question

I have an application which consists of message driven bean and a couple of session beans. One of them has a DAO object, that is responsible for accessing database or FTP server.

I need to have two applications. The only difference between them is the instance of DAO class. Can I specify that instance during the deployment phase?

My purpose is to avoid code duplication.

What exactly do you mean by the word instance? A class file or an existing object already in memory? — home, Jun 09 '12 at 12:52
I mean an existing object in memory. Let's say that DAO is an interface and I want to choose the implementation during deployment — Dmitry D, Jun 09 '12 at 13:37

score 1 · Accepted Answer · answered Jun 10 '12 at 15:53

If the DAO is just a POJO, then I would suggest a Class env-entry if you're using EE6 (or a String env-entry if you're not, and then do the Class.forName yourself):

<env-entry>
  <env-entry-name>daoClass</env-entry-name>
  <env-entry-type>java.lang.Class</env-entry-type>
  <!-- Specify a default, override at deployment time. -->
  <env-entry-value>com.example.project.DefaultDAO</env-entry-value>
</env-entry>

@Resource(name="daoClass")
private void setDAOClass(Class<com.example.project.DAO> daoClass) {
    this.dao = daoClass.newInstance();
}

Alternatively, if your DAO implementation were an EJB, then you could use @EJB injection, and specify the binding name at deployment time.

Can I reuse a session bean with another injected classes?

1 Answers1