make server pings not block each other

common/src/main/java/us/ajg0702/queue/common/QueueManagerImpl.java

@@ -19,6 +19,8 @@ import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.ThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
 
 public class QueueManagerImpl implements QueueManager {
@@ -474,9 +476,14 @@ public class QueueManagerImpl implements QueueManager {
 
     @Override
     public void updateServers() {
+        ExecutorService pool = main.getTaskManager().getServersUpdateExecutor();
+        if (pool instanceof ThreadPoolExecutor && main.getConfig().getBoolean("pinger-debug")) {
+            main.getLogger().info("[pinger] Server update thread pool has "
+                    +((ThreadPoolExecutor) pool).getActiveCount()+" threads");
+        }
         try {
             for(QueueServer server : servers) {
-                server.updatePing();
+                pool.submit(server::updatePing);
             }
         } catch(Exception e) {
             e.printStackTrace();

common/src/main/java/us/ajg0702/queue/common/TaskManager.java

@@ -2,10 +2,7 @@ package us.ajg0702.queue.common;
 
 import java.util.Arrays;
 import java.util.List;
-import java.util.concurrent.Executors;
-import java.util.concurrent.ScheduledExecutorService;
-import java.util.concurrent.ScheduledFuture;
-import java.util.concurrent.TimeUnit;
+import java.util.concurrent.*;
 
 public class TaskManager {
 
@@ -13,6 +10,8 @@ public class TaskManager {
     final ScheduledExecutorService executor = Executors.newScheduledThreadPool(1);
     final ScheduledExecutorService updateExecutor = Executors.newScheduledThreadPool(1);
 
+    final ExecutorService serversUpdateExecutor = Executors.newCachedThreadPool();
+
     final QueueMain main;
     public TaskManager(QueueMain main) {
         this.main = main;
@@ -21,6 +20,11 @@ public class TaskManager {
     public void shutdown() {
         executor.shutdown();
         updateExecutor.shutdown();
+        serversUpdateExecutor.shutdown();
+    }
+
+    public ExecutorService getServersUpdateExecutor() {
+        return serversUpdateExecutor;
     }
 
     public String taskStatus() {
@@ -52,7 +56,7 @@ public class TaskManager {
         updateTask = scheduleAtFixedRate(updateExecutor,
                 main.getQueueManager()::updateServers,
                 500L,
-                (long) (Math.max(main.getTimeBetweenPlayers()/2, 2)*1000L),
+                (long) (Math.max(main.getTimeBetweenPlayers()/2, 1)*1000L),
                 TimeUnit.MILLISECONDS
         );