OO-1052: use a concurrent list to maintain the messages history of a chat

src/main/java/org/olat/core/dispatcher/mapper/MapperDispatcher.java

@@ -98,11 +98,13 @@ public class MapperDispatcher extends LogDelegator implements Dispatcher {
 		UserSession usess = CoreSpringFactory.getImpl(UserSessionManager.class).getUserSession(hreq);
 		Mapper m = CoreSpringFactory.getImpl(MapperService.class).getMapperById(usess, smappath);
 		if (m == null) {
-			logWarn(
-					"Call to mapped resource, but mapper does not exist for path::"
-							+ pathInfo, null);
-			DispatcherModule.sendNotFound(pathInfo, hres);
-			return;
+			//an anonymous mapper?
+			m = CoreSpringFactory.getImpl(MapperService.class).getMapperById(null, smappath);
+			if(m == null) {
+				logWarn("Call to mapped resource, but mapper does not exist for path::" + smappath, null);
+				DispatcherModule.sendNotFound(pathInfo, hres);
+				return;
+			}
 		}
 		String mod = slashPos > 0 ? subInfo.substring(slashPos) : "";
 		if (mod.indexOf("..") != -1) {

src/main/java/org/olat/core/gui/control/controller/BasicController.java

@@ -48,6 +48,7 @@ import org.olat.core.id.Identity;
 import org.olat.core.logging.AssertException;
 import org.olat.core.logging.OLog;
 import org.olat.core.logging.Tracing;
+import org.olat.core.util.UserSession;
 import org.olat.core.util.Util;
 
 /**
@@ -229,12 +230,13 @@ public abstract class BasicController extends DefaultController {
 		if (mappers == null) {
 			mappers = new ArrayList<Mapper>(2);
 		}
-		String mapperBaseURL; 
+		String mapperBaseURL;
+		UserSession usess = ureq == null ? null : ureq.getUserSession();
 		if (cacheableMapperID == null) {
 			// use non cacheable as fallback
-			mapperBaseURL =  CoreSpringFactory.getImpl(MapperService.class).register(ureq.getUserSession(), m);			
+			mapperBaseURL =  CoreSpringFactory.getImpl(MapperService.class).register(usess, m);			
 		} else {
-			mapperBaseURL =  CoreSpringFactory.getImpl(MapperService.class).register(ureq.getUserSession(), cacheableMapperID, m, expirationTime);
+			mapperBaseURL =  CoreSpringFactory.getImpl(MapperService.class).register(usess, cacheableMapperID, m, expirationTime);
 		}
 		// registration was successful, add to our mapper list
 		mappers.add(m);

src/main/java/org/olat/instantMessaging/ui/ChatController.java

@@ -28,9 +28,11 @@ package org.olat.instantMessaging.ui;
 import java.util.ArrayList;
 import java.util.Calendar;
 import java.util.Date;
+import java.util.Deque;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.concurrent.LinkedBlockingDeque;
 
 import javax.servlet.http.HttpServletRequest;
 
@@ -79,7 +81,7 @@ public class ChatController extends BasicController implements GenericEventListe
 	private final VelocityContainer chatMsgFieldContent;
 
 	private Map<Long,String> avatarKeyCache = new HashMap<Long,String>();
-	private List<ChatMessage> messageHistory = new ArrayList<ChatMessage>();
+	private Deque<ChatMessage> messageHistory = new LinkedBlockingDeque<>();
 
 	private Link refresh, todayLink, lastWeek, lastMonth;
 	private JSAndCSSComponent jsc;
@@ -343,25 +345,21 @@ public class ChatController extends BasicController implements GenericEventListe
 			creationDate = formatter.formatDateAndTime(message.getCreationDate());
 		}
 
+		boolean first = true;
 		String from = message.getFromNickName();
-		
-		synchronized (messageHistory) {
-			boolean first = true;
-			if(!messageHistory.isEmpty()) {
-				ChatMessage last = messageHistory.get(messageHistory.size() - 1);
-				if(from.equals(last.getFrom())) {
-					first = false;
-				}
-			}
+		ChatMessage last = messageHistory.peekLast();
+		if(last != null && from.equals(last.getFrom())) {
+			first = false;
+		}
 
-			boolean anonym = message.isAnonym();
-			Long fromKey = message.getFromKey();
-			ChatMessage msg = new ChatMessage(creationDate, from, fromKey, m, first, anonym);
-			if(!anonym ) {
-				msg.setAvatarKey(getAvatarKey(message.getFromKey()));
-			}
-			messageHistory.add(msg);
+		boolean anonym = message.isAnonym();
+		Long fromKey = message.getFromKey();
+		ChatMessage msg = new ChatMessage(creationDate, from, fromKey, m, first, anonym);
+		if(!anonym ) {
+			msg.setAvatarKey(getAvatarKey(message.getFromKey()));
 		}
+		messageHistory.addLast(msg);
+
 		chatMsgFieldContent.contextPut("chatMessages", messageHistory);
 		chatMsgFieldContent.contextPut("focus", new Boolean(focus));
 	}