fixed bug: double answering with deferred message if user prints into chat very quickly

pom.xml

@@ -6,7 +6,7 @@
 
     <groupId>ru.bvn13</groupId>
     <artifactId>jircbot</artifactId>
-    <version>2.2.1</version>
+    <version>2.2.2</version>
     <packaging>jar</packaging>
 
     <parent>
@@ -18,8 +18,6 @@
 
 
     <properties>
-        <bot.version>2.2.1</bot.version>
-
         <java.version>1.8</java.version>
 
         <pircbotx.version>2.3-SNAPSHOT</pircbotx.version>

src/main/java/ru/bvn13/jircbot/listeners/DeferredMessagesListener.java

@@ -16,7 +16,10 @@ import ru.bvn13.jircbot.documentation.DocumentationProvider;
 import ru.bvn13.jircbot.documentation.ListenerDescription;
 
 import java.text.SimpleDateFormat;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
 
 import static ru.bvn13.jircbot.documentation.ListenerDescription.CommandDescription;
 
@@ -36,6 +39,8 @@ public class DeferredMessagesListener extends ImprovedListenerAdapter implements
 
     private DeferredMessageService deferredMessageService;
 
+    private Map<String, Object> mutexes = new ConcurrentHashMap<>();
+
     @Autowired
     public DeferredMessagesListener(DocumentationProvider documentationProvider) {
         registerDescription(documentationProvider);
@@ -127,12 +132,14 @@ public class DeferredMessagesListener extends ImprovedListenerAdapter implements
 
     }
 
-
     private void sendDeferredMessage(final MessageEvent event) {
 
         if (event.getUser() != null) {
             String userIdent = event.getUser().getNick() + "!" + event.getUser().getLogin() + "@" + event.getUser().getHostname();
+            Object mutex = mutexes.containsKey(userIdent) ? mutexes.get(userIdent) : new Object();
+            mutexes.put(userIdent, mutex);
 
+            synchronized (mutex) {
                 List<DeferredMessage> deferredMessages = deferredMessageService.getDeferredMessagesForUser(this.getChannelName(event), event.getUser().getNick().toLowerCase(), userIdent);
                 if (deferredMessages != null && deferredMessages.size() > 0) {
                     DeferredMessage msg = deferredMessages.get(0);
@@ -142,6 +149,7 @@ public class DeferredMessagesListener extends ImprovedListenerAdapter implements
                 }
             }
         }
+    }
 
     @Override
     public void onJoin(JoinEvent event) throws Exception {

src/main/resources/application.properties

@@ -1,5 +1,5 @@
 
-jircbot.version=2.2.1
+jircbot.version=2.2.2
 
 jircbot.config=config.json