Purging stale broadcasts moved to getStatus

rather than periodically on schedule.  This change has
no impact on user experience, and has improved logic,
and slight improvement in performance.

Also made all changes to the broadcasts structure under
synchronized control.

src/main/java/altk/comm/engine/CommEngine.java

@@ -7,12 +7,11 @@ import java.io.IOException;
 import java.io.PrintWriter;
 import java.util.Enumeration;
 import java.util.HashMap;
+import java.util.Iterator;
 import java.util.Map;
 import java.util.Properties;
 import java.util.Vector;
-import java.util.concurrent.Executors;
 import java.util.concurrent.ScheduledExecutorService;
-import java.util.concurrent.TimeUnit;
 
 import javax.servlet.ServletContext;
 import javax.servlet.http.HttpServlet;
@@ -195,10 +194,6 @@ public abstract class CommEngine extends HttpServlet
         CommonLogger.activity.info("Postback threadpool size = " + getPostbackSenderPoolSize());
         CommonLogger.activity.info("Postback max batch size = " + getPostbackMaxBatchSize());
         
-        scheduler = Executors.newScheduledThreadPool(SCHEDULER_THREAD_POOL_SIZE);
-        scheduler.scheduleAtFixedRate(new Runnable() { public void run() { purgeStaleBroadcasts();}},
-                deadBroadcastViewingMinutes, deadBroadcastViewingMinutes, TimeUnit.MINUTES);
-
         initChild();
     }
     
@@ -261,13 +256,14 @@ public abstract class CommEngine extends HttpServlet
         long now = System.currentTimeMillis();
         synchronized (broadcasts)
         {
-            for (String id : broadcasts.keySet())
+            Iterator<String> iter = broadcasts.keySet().iterator();
+            while (iter.hasNext())
             {
-                if (now - broadcasts.get(id).changeStateTime > deadBroadcastViewingMinutes * 60 * 1000)
+            	Broadcast broadcast = broadcasts.get(iter.next());
+				if (now - broadcast.changeStateTime > deadBroadcastViewingMinutes * 60 * 1000)
                 {
-                    Broadcast broadcast = broadcasts.get(id);
                     completedJobCount += broadcast.getCompletedJobCount();
-                    broadcasts.remove(id);
+                    iter.remove();
                 }
             }
         }
@@ -393,6 +389,7 @@ public abstract class CommEngine extends HttpServlet
      */
     private void getStatus(HttpServletRequest request, PrintWriter out)
     {
+    	purgeStaleBroadcasts();
         String broadcastId = request.getParameter("broadcast_id");
         if (broadcastId != null)
         {
@@ -515,11 +512,13 @@ public abstract class CommEngine extends HttpServlet
         // Shutdown threads that periodically purge stale broadcasts.
         scheduler.shutdownNow();
         
-        for (Broadcast broadcast : broadcasts.values())
+        synchronized(broadcasts)
         {
-        	broadcast.terminate(BroadcastState.ABORTED, "Platform termination");
+	        for (Broadcast broadcast : broadcasts.values())
+	        {
+	        	broadcast.terminate(BroadcastState.ABORTED, "Platform termination");
+	        }
         }
-        
         destroyChild();
         super.destroy();
     }
@@ -542,8 +541,10 @@ public abstract class CommEngine extends HttpServlet
     public void addBroadcast(String broadcastId, Broadcast broadcast)
     {
         if (broadcastId == null) broadcastId = "Unknown" + unknownBroadcastIdNdx++;
-        broadcasts.put(broadcastId,  broadcast);
-        
+        synchronized (broadcasts)
+        {
+        	broadcasts.put(broadcastId,  broadcast);
+        }	
     }
 
     /**
@@ -554,7 +555,10 @@ public abstract class CommEngine extends HttpServlet
     {
         String broadcastId = broadcast.getBroadcastId();
         if (broadcastId == null) broadcastId = "Unknown" + unknownBroadcastIdNdx++;
-        broadcasts.put(broadcastId,  broadcast);
+        synchronized (broadcasts)
+        {
+        	broadcasts.put(broadcastId,  broadcast);
+        }
     }
 
 }