I have a problem to refresh or reload an application scoped managed bean. It behaves as cached data bean. So once data is changed on db side, i want to reload the the list in the bean. Is there anyway to refresh/reload t开发者_开发技巧he list, say once a day based on given time? Thanks
Just add a method to the aplication scoped bean which does exactly that.
public void reload() {
list = dao.list();
}
Then grab/inject this bean in another bean and call the method.
data.reload();
Update sorry, I overlooked the "once a day" bit. You mean automatic reloading in the background? This is best to be achieved by a background thread which is managed by ScheduledExecutorService
. Create a ServletContextListener
like follows:
@WebListener
public class Config implements ServletContextListener {
private ScheduledExecutorService scheduler;
@Override
public void contextInitialized(ServletContextEvent event) {
Reloader reloader = new Reloader(event.getServletContext());
scheduler = Executors.newSingleThreadScheduledExecutor();
scheduler.scheduleAtFixedRate(reloader, 1, 1, TimeUnit.DAYS);
}
@Override
public void contextDestroyed(ServletContextEvent event) {
scheduler.shutdownNow();
}
}
Where the class Reloader
look like this (assuming that the managed bean name is data
)
public class Reloader implements Runnable {
private ServletContext context;
public Reloader(ServletContext context) {
this.context = context;
}
@Override
public void run() {
Data data = (Data) context.getAttribute("data");
if (data != null) {
data.reload();
}
}
}
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