Question

I’m new to using Servlets so please forgive me if I use incorrect terminology. I have an Object called “Provider” in JSF Bean Class “Detector” which needs to be instantiated once and then can be used for all other requests. I’ve done some searching and found the ServletContextListener interface which seems to do what I need. Ive mentioned it in my web.xml file like so:

<listener>
    <listener-class>
        p1.ContextListener
    </listener-class>
</listener>

and the class looks like this:

package p1;

import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;

public class ContextListener implements ServletContextListener{

   @Override
   public void contextInitialized(ServletContextEvent sce) {
      Detector.startProvider();
   }

   @Override
   public void contextDestroyed(ServletContextEvent sce) {
     Provider.dispose();
   }  
}

And here is my Detector Class:

package p1;

import javax.faces.bean.ManagedBean;
import javax.faces.context.FacesContext;
import javax.servlet.http.HttpServletRequest;


@ManagedBean
public class Detector{

    private static Provider p;
    FacesContext context;
    String userAgent;

    public Detector() {
        context = FacesContext.getCurrentInstance();
    }

    public String getValue() {
        return p.getValue();
    }

    public String getUserAgent() {
        return ((HttpServletRequest) context.getExternalContext().getRequest()).getHeader("User-Agent");
    }

    public static void startProvider(){
        p = Creater.create();
    }
}

My code all works, but the only way that seems right to me is to have the Provider Object as a static but that seems like a bad idea in an Bean that will be used for different requests. My question is whether it is right to have the Provider Object as a static?

Answer 1

I found the answer I need on this question JSF initialize application-scope bean when context initialized. I set the Provider Object as an attribute of the ServletContextEvent in my “ContextListener” and retrieved it in my Detector class from my FacesContext Object “context”. (This is shown in more detail in the accepted answer of the link provided)