Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>You are running while loop inside <strong><em>contextInitialized()</em></strong> method which is wrong. <strong><em>contextInitialized()</em></strong> is invoked by Servlet Container as part of the application startup, having while loop there will block your app start. </p> <p>Modified the code such the ContextListener will start one daemon thread which publishes the messages to the watchers</p> <pre><code>@WebListener public class ChatPushService implements ServletContextListener { @Override public void contextInitialized(ServletContextEvent sce) { final List&lt;AsyncContext&gt; watchers = new ArrayList&lt;AsyncContext&gt;(); sce.getServletContext().setAttribute("watchers", watchers); // store new messages not published yet Queue&lt;String&gt; messages = new ConcurrentLinkedQueue&lt;String&gt;(); sce.getServletContext().setAttribute("messages", messages); new chatManager(sce.getServletContext()).start(); //START DAEMON } } public class ChatManager implements Runnable { ServletContext servletCtx; public ChatManager(ServletContext ctx) { this.servletCtx = ctx; } public void run() { List&lt;AsyncContext&gt; watchers = (List&lt;AsyncContext&gt;) servletCtx.getAttribute("watchers"); Queue&lt;String&gt; messages = (Queue&lt;String&gt;)appScope.getAttribute("messages"); Executor messageExecutor = Executors.newCachedThreadPool(); final Executor watcherExecutor = Executors.newCachedThreadPool(); while(true) { if(!messages.isEmpty()) { System.out.println("notEmpty"); String message = messages.poll(); messageExecutor.execute(new Runnable(){ @Override public void run() { for(final AsyncContext aCtx : watchers){ watcherExecutor.execute(new Runnable(){ @Override public void run() { try { aCtx.getResponse().getWriter().print("brrrrr"); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } }); } } }); } } } } </code></pre>
    singulars
    1. This table or related slice is empty.
    1. POServlet 3 Async task on Tomcat 7
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USRamesh PVK
    1. USRamesh PVK
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. POServlet 3 Async task on Tomcat 7
      singulars
      1. PTQuestion
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTAcceptedByOriginator
    3. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. COThat part also surprised me, but that code was presented as such in the Javaworld's article which the OP copied from, so the OP isn't to blame here.
      singulars
      1. PO
      1. USBalusC
    2. COI'm trying to create chat where each message submitted by POST will be delivered to all clients Subscribed there, So kind of queue created and while(true) block monitors if this new message already in queue.
      singulars
      1. PO
      1. USdanny.lesnik
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload