使用session.setAttribute复制会话对象

Question

I have a Cluster as Standalone Instances with Hazelcast and Payara, I added a Session Replication and a Load Balancer with HAProxy. Everything works fine.

When I use a Session Bean all global variables are replicated to the nodes of the cluster but when I try to share an object in a no-SessionBean a few times it doesn't work. This below is my simple example:

I have a simple page that retrieve 2 list of "String" (Hazelcast Distributed List and Session List):

Index Page

The Bean behind the page has a custom scope.

@Named
@RomeoScoped  //this is my custom scope
public class RomeoBean implements Serializable {

The "increase" method is called when I click on the "add" button:

public void increase(){
    FacesContext currentInstance = FacesContext.getCurrentInstance();
    HttpServletRequest request = (HttpServletRequest) currentInstance.getExternalContext().getRequest();
    HttpSession session = request.getSession();

    String example  = Math.random() + "";

    if(session != null){
       CopyOnWriteArrayList<String> list = (CopyOnWriteArrayList<String>) session.getAttribute("List");
       list.add(example);
       session.setAttribute("List", list);
    }

    try {
       Context ctx = new InitialContext();
       HazelcastInstance instance = (HazelcastInstance)    ctx.lookup("payara/Hazelcast");
       IList<String> list = instance.getList("list");
       list.add(example);
    } catch (NamingException ex) {
       Logger.getLogger(RomeoBean.class.getName()).log(Level.SEVERE, null, ex);
    }
}

After 4 clicks on the button, the situazione is this:

Click for view Example

Only 2 Strings are shared in Session List, while all Strings with Hazelcast. I need to use my custom scope and in same case the objects must be shared only in the session and not in application (as Hazelcast Distributed List).

Can I fix the problem with "setAttribute" method?

Thanks in advance for the support.

Answer 1

In order to make session replication working over Hazelcast in Payara Server, you need to enable Web Container Availability over Hazelcast. See this screenshot .

You also need to include the <distributable/> element into the web.xml in your application, otherwise the session will not be distributed.