world hopper: change ping task to ping one world

This will allow other tasks that are scheduled on the hopper executor to
not be blocked for long periods of time due to the world pinger.

This pings, at fixed delay, each world every 3 seconds, which for 200
worlds is at most as often as the previous mass-ping every 10 minutes.

runelite-client/src/main/java/net/runelite/client/plugins/worldhopper/WorldHopperPlugin.java

@@ -96,7 +96,6 @@ import org.apache.commons.lang3.ArrayUtils;
 public class WorldHopperPlugin extends Plugin
 {
 	private static final int WORLD_FETCH_TIMER = 10;
-	private static final int WORLD_PING_TIMER = 10;
 	private static final int REFRESH_THROTTLE = 60_000; // ms
 	private static final int TICK_THROTTLE = (int) Duration.ofMinutes(10).toMillis();
 
@@ -146,6 +145,7 @@ public class WorldHopperPlugin extends Plugin
 
 	private ScheduledFuture<?> worldResultFuture, pingFuture;
 	private WorldResult worldResult;
+	private int currentWorld;
 	private Instant lastFetch;
 	private boolean firstRun;
 
@@ -201,10 +201,14 @@ public class WorldHopperPlugin extends Plugin
 		}
 
 		panel.setFilterMode(config.subscriptionFilter());
+
+		// The plugin has its own executor for pings, as it blocks for a long time
+		hopperExecutorService = new ExecutorServiceExceptionLogger(Executors.newSingleThreadScheduledExecutor());
+		// On first run this schedules an initial ping on hopperExecutorService
 		worldResultFuture = executorService.scheduleAtFixedRate(this::tick, 0, WORLD_FETCH_TIMER, TimeUnit.MINUTES);
 
-		hopperExecutorService = new ExecutorServiceExceptionLogger(Executors.newSingleThreadScheduledExecutor());
-		pingFuture = hopperExecutorService.scheduleAtFixedRate(this::pingWorlds, WORLD_PING_TIMER, WORLD_PING_TIMER, TimeUnit.MINUTES);
+		// Give some initial delay - this won't run until after pingInitialWorlds finishes from tick() anyway
+		pingFuture = hopperExecutorService.scheduleWithFixedDelay(this::pingNextWorld, 15, 3, TimeUnit.SECONDS);
 	}
 
 	@Override
@@ -459,7 +463,8 @@ public class WorldHopperPlugin extends Plugin
 		if (firstRun)
 		{
 			firstRun = false;
-			hopperExecutorService.execute(this::pingWorlds);
+			// On first run we ping all of the worlds at once to initialize the ping values
+			hopperExecutorService.execute(this::pingInitialWorlds);
 		}
 	}
 
@@ -755,7 +760,10 @@ public class WorldHopperPlugin extends Plugin
 		return null;
 	}
 
-	private void pingWorlds()
+	/**
+	 * Ping all worlds. This takes a long time and is only run on first run.
+	 */
+	private void pingInitialWorlds()
 	{
 		if (worldResult == null || !config.showSidebar() || !config.ping())
 		{
@@ -774,4 +782,33 @@ public class WorldHopperPlugin extends Plugin
 
 		log.debug("Done pinging worlds in {}", stopwatch.elapsed());
 	}
+
+	/**
+	 * Ping the next world
+	 */
+	private void pingNextWorld()
+	{
+		if (worldResult == null || !config.showSidebar() || !config.ping())
+		{
+			return;
+		}
+
+		List<World> worlds = worldResult.getWorlds();
+		if (worlds.isEmpty())
+		{
+			return;
+		}
+
+		if (currentWorld >= worlds.size())
+		{
+			// Wrap back around
+			currentWorld = 0;
+		}
+
+		World world = worlds.get(currentWorld++);
+
+		int ping = Ping.ping(world);
+		log.trace("Ping for world {} is: {}", world.getId(), ping);
+		SwingUtilities.invokeLater(() -> panel.updatePing(world.getId(), ping));
+	}
 }