Drop previous match requests from the bot on a new connection; Run matches in parallel

Author: episarenko

server/src/main/java/ru/croccode/hypernull/server/HyperNull.java

@@ -63,18 +63,19 @@ public HyperNull(Properties properties) throws IOException {
 	public void run() {
 		List<MatchMode> modes = Arrays.asList(MatchMode.FRIENDLY, MatchMode.DEATHMATCH);
 		while (true) {
-			List<MatchRequest> matchRequests = Collections.emptyList();
 			Collections.shuffle(modes);
+			boolean matchStarted = false;
 			for (MatchMode mode : modes) {
-				matchRequests = server.pollRequests(
+				List<MatchRequest> matchRequests = server.pollRequests(
 						mode,
 						mode == MatchMode.FRIENDLY ? MIN_FRIENDLY_BOTS : MIN_DEATHMATCH_BOTS,
 						mode == MatchMode.FRIENDLY ? MAX_FRIENDLY_BOTS : MAX_DEATHMATCH_BOTS);
 				if (!matchRequests.isEmpty()) {
 					runMatch(mode, matchRequests);
+					matchStarted = true;
 				}
 			}
-			if (matchRequests.isEmpty()) {
+			if (!matchStarted) {
 				try {
 					Thread.sleep(1_000L);
 				} catch (InterruptedException e) {
@@ -118,7 +119,7 @@ private void runMatch(MatchMode mode, List<MatchRequest> matchRequests) {
 					.map(r -> r.getBotName() + " [" + r.getMode() + "]")
 					.collect(Collectors.joining(", "));
 			System.out.println("Starting match " + matchId + ": " + bots);
-			new MatchRunner(match, botSessions).run();
+			ThreadPools.matchPool().submit(new MatchRunner(match, botSessions));
 		}
 	}
 

server/src/main/java/ru/croccode/hypernull/server/Server.java

@@ -9,8 +9,10 @@
 import java.util.Collections;
 import java.util.Deque;
 import java.util.HashMap;
+import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 import java.util.concurrent.locks.Lock;
 import java.util.concurrent.locks.ReentrantLock;
 
@@ -95,6 +97,21 @@ private void sessionOpened(SocketSession session) {
 	private void offerRequest(MatchRequest request) {
 		lock.lock();
 		try {
+			// discard previous match requests of the bot (by name)
+			queues.values().forEach(q -> {
+				Iterator<MatchRequest> it = q.iterator();
+				while (it.hasNext()) {
+					MatchRequest prev = it.next();
+					if (!Objects.equals(prev.getBotName(), request.getBotName()))
+						continue;
+					// close request session
+					try {
+						prev.getSession().close();
+					} catch (IOException ignore) {
+					}
+					it.remove();
+				}
+			});
 			queues
 					.computeIfAbsent(request.getMode(), k -> new ArrayDeque<>())
 					.offer(request);

server/src/main/java/ru/croccode/hypernull/server/ThreadPools.java

@@ -5,16 +5,25 @@
 
 public final class ThreadPools {
 
+	private static final int MAX_PARALLEL_MATCHES = 20;
+
 	private static final ExecutorService DEFAULT_POOL = Executors.newCachedThreadPool();
 
+	private static final ExecutorService MATCH_POOL = Executors.newFixedThreadPool(MAX_PARALLEL_MATCHES);
+
 	private ThreadPools() {
 	}
 
 	public static ExecutorService defaultPool() {
 		return DEFAULT_POOL;
 	}
 
+	public static ExecutorService matchPool() {
+		return MATCH_POOL;
+	}
+
 	public static void shutdownAll() {
+		MATCH_POOL.shutdownNow();
 		DEFAULT_POOL.shutdownNow();
 	}
 }