remove dead clients

refactor the injector out to the servlet context

WebContent/WEB-INF/web.xml

@@ -0,0 +1,44 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" version="3.0">
+  <display-name>cah</display-name>
+  <welcome-file-list>
+    <welcome-file>index.html</welcome-file>
+    <welcome-file>index.htm</welcome-file>
+    <welcome-file>index.jsp</welcome-file>
+  </welcome-file-list>
+  <servlet>
+    <servlet-name>TestServlet</servlet-name>
+    <servlet-class>net.socialgamer.cah.TestServlet</servlet-class>
+  </servlet>
+  <servlet>
+    <servlet-name>LongPollServlet</servlet-name>
+    <servlet-class>net.socialgamer.cah.LongPollServlet</servlet-class>
+  </servlet>
+  <servlet>
+    <servlet-name>AjaxServlet</servlet-name>
+    <servlet-class>net.socialgamer.cah.AjaxServlet</servlet-class>
+  </servlet>
+  <servlet>
+    <servlet-name>Schema</servlet-name>
+    <servlet-class>net.socialgamer.cah.Schema</servlet-class>
+  </servlet>
+  <servlet-mapping>
+    <servlet-name>TestServlet</servlet-name>
+    <url-pattern>/TestServlet</url-pattern>
+  </servlet-mapping>
+  <servlet-mapping>
+    <servlet-name>LongPollServlet</servlet-name>
+    <url-pattern>/LongPollServlet</url-pattern>
+  </servlet-mapping>
+  <servlet-mapping>
+    <servlet-name>AjaxServlet</servlet-name>
+    <url-pattern>/AjaxServlet</url-pattern>
+  </servlet-mapping>
+  <servlet-mapping>
+    <servlet-name>Schema</servlet-name>
+    <url-pattern>/Schema</url-pattern>
+  </servlet-mapping>
+  <listener>
+    <listener-class>net.socialgamer.cah.StartupUtils</listener-class>
+  </listener>
+</web-app>

src/net/socialgamer/cah/AjaxServlet.java

@@ -4,11 +4,8 @@ import java.io.IOException;
 import java.io.PrintWriter;
 import java.util.Map;
 
-import javax.servlet.Servlet;
-import javax.servlet.ServletConfig;
 import javax.servlet.ServletException;
 import javax.servlet.annotation.WebServlet;
-import javax.servlet.http.HttpServlet;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 import javax.servlet.http.HttpSession;
@@ -16,9 +13,6 @@ import javax.servlet.http.HttpSession;
 import net.socialgamer.cah.handlers.Handler;
 import net.socialgamer.cah.handlers.Handlers;
 
-import com.google.inject.Guice;
-import com.google.inject.Injector;
-
 
 /**
  * Servlet implementation class AjaxServlet
@@ -29,25 +23,6 @@ import com.google.inject.Injector;
 public class AjaxServlet extends CahServlet {
   private static final long serialVersionUID = 1L;
 
-  private final Injector injector;
-
-  /**
-   * @see HttpServlet#HttpServlet()
-   */
-  public AjaxServlet() {
-    super();
-
-    injector = Guice.createInjector();
-  }
-
-  /**
-   * @see Servlet#init(ServletConfig)
-   */
-  @Override
-  public void init(final ServletConfig config) throws ServletException {
-    // TODO Auto-generated method stub
-  }
-
   /**
    * @see CahServlet#doPost(HttpServletRequest request, HttpServletResponse response, HttpSession
    *      hSession)
@@ -76,7 +51,7 @@ public class AjaxServlet extends CahServlet {
 
     final Handler handler;
     try {
-      handler = injector.getInstance(Handlers.LIST.get(op));
+      handler = getInjector().getInstance(Handlers.LIST.get(op));
     } catch (final Exception e) {
       returnError(out, "bad_op", "Invalid operation.", serial);
       return;

src/net/socialgamer/cah/CahModule.java

@@ -8,7 +8,6 @@ public class CahModule extends AbstractModule {
 
   @Override
   protected void configure() {
-    // TODO Auto-generated method stub
     bind(Server.class).in(Singleton.class);
   }
 }

src/net/socialgamer/cah/CahServlet.java

@@ -13,6 +13,8 @@ import javax.servlet.http.HttpSession;
 import org.json.simple.JSONObject;
 import org.json.simple.JSONValue;
 
+import com.google.inject.Injector;
+
 
 /**
  * Servlet implementation class CahServlet
@@ -109,4 +111,7 @@ public abstract class CahServlet extends HttpServlet {
     writer.println(JSONValue.toJSONString(data));
   }
 
+  protected Injector getInjector() {
+    return (Injector) getServletContext().getAttribute(StartupUtils.INJECTOR);
+  }
 }

src/net/socialgamer/cah/StartupUtils.java

@@ -0,0 +1,48 @@
+package net.socialgamer.cah;
+
+import java.util.Timer;
+
+import javax.servlet.ServletContext;
+import javax.servlet.ServletContextEvent;
+
+import com.google.inject.Guice;
+import com.google.inject.Injector;
+import com.google.inject.servlet.GuiceServletContextListener;
+
+
+public class StartupUtils extends GuiceServletContextListener {
+
+  public static final String INJECTOR = "injector";
+
+  private static final long PING_START_DELAY = 60 * 1000;
+
+  private static final long PING_CHECK_DELAY = 5 * 1000;
+
+  private static final String PING_TIMER_NAME = "ping_timer";
+
+  @Override
+  public void contextDestroyed(final ServletContextEvent contextEvent) {
+    final ServletContext context = contextEvent.getServletContext();
+    final Timer timer = (Timer) context.getAttribute(PING_TIMER_NAME);
+    assert (timer != null);
+    timer.cancel();
+    context.removeAttribute(PING_TIMER_NAME);
+    context.removeAttribute(INJECTOR);
+  }
+
+  @Override
+  public void contextInitialized(final ServletContextEvent contextEvent) {
+    final ServletContext context = contextEvent.getServletContext();
+    final Injector injector = getInjector();
+    final UserPing ping = injector.getInstance(UserPing.class);
+    final Timer timer = new Timer();
+    timer.schedule(ping, PING_START_DELAY, PING_CHECK_DELAY);
+    context.setAttribute(PING_TIMER_NAME, timer);
+    context.setAttribute(INJECTOR, injector);
+  }
+
+  @Override
+  protected Injector getInjector() {
+    return Guice.createInjector();
+  }
+}

src/net/socialgamer/cah/UserPing.java

@@ -0,0 +1,23 @@
+package net.socialgamer.cah;
+
+import java.util.TimerTask;
+
+import net.socialgamer.cah.data.ConnectedUsers;
+
+import com.google.inject.Inject;
+
+
+public class UserPing extends TimerTask {
+
+  private final ConnectedUsers users;
+
+  @Inject
+  public UserPing(final Server server) {
+    users = server.getConnectedUsers();
+  }
+
+  @Override
+  public void run() {
+    users.checkForPingTimeouts();
+  }
+}

src/net/socialgamer/cah/data/ConnectedUsers.java

@@ -2,9 +2,11 @@ package net.socialgamer.cah.data;
 
 import java.util.Collection;
 import java.util.HashMap;
+import java.util.Iterator;
 import java.util.Map;
 
 import net.socialgamer.cah.data.QueuedMessage.Type;
+import net.socialgamer.cah.data.User.DisconnectReason;
 
 
 /**
@@ -16,6 +18,11 @@ import net.socialgamer.cah.data.QueuedMessage.Type;
  */
 public class ConnectedUsers {
 
+  /**
+   * Duration of a ping timeout, in nanoseconds.
+   */
+  public static final long PING_TIMEOUT = 3L * 60L * 1000L * 1000000L;
+
   private final Map<String, User> users = new HashMap<String, User>();
 
   public boolean hasUser(final String userName) {
@@ -33,10 +40,31 @@ public class ConnectedUsers {
   }
 
   public void removeUser(final User user, final User.DisconnectReason reason) {
-    // TODO fire an event for a disconnected user to interested parties
+    synchronized (users) {
-    //    synchronized (users) {
+      users.remove(user.getNickname());
-    //
+      notifyRemoveUser(user, reason);
-    //    }
+    }
+  }
+
+  private void notifyRemoveUser(final User user, final User.DisconnectReason reason) {
+    final HashMap<String, Object> data = new HashMap<String, Object>();
+    data.put("event", "player_leave");
+    data.put("nickname", user.getNickname());
+    data.put("reason", reason.toString());
+    broadcastToAll(Type.PLAYER_DISCONNECT, data);
+  }
+
+  public void checkForPingTimeouts() {
+    synchronized (users) {
+      final Iterator<User> iterator = users.values().iterator();
+      while (iterator.hasNext()) {
+        final User u = iterator.next();
+        if (System.nanoTime() - u.getLastHeardFrom() > PING_TIMEOUT) {
+          notifyRemoveUser(u, DisconnectReason.PING_TIMEOUT);
+          iterator.remove();
+        }
+      }
+    }
   }
 
   /**