From 939c36bfa9fda11e14101a3552400f0137ced60c Mon Sep 17 00:00:00 2001
From: Jan Belle
Date: Fri, 31 Aug 2018 12:58:10 +0200
Subject: Bug 538485 [runtime.java] Fix race condition in message service

Change-Id: Iab3011b0415fb7b50a443c39ba3c82ec1857b4cf
---
 .../runtime/java/messaging/MessageSeQueue.java     |  6 +++-
 .../runtime/java/messaging/MessageService.java     | 37 +++++++++++-----------
 2 files changed, 23 insertions(+), 20 deletions(-)

diff --git a/runtime/org.eclipse.etrice.runtime.java/src/org/eclipse/etrice/runtime/java/messaging/MessageSeQueue.java b/runtime/org.eclipse.etrice.runtime.java/src/org/eclipse/etrice/runtime/java/messaging/MessageSeQueue.java
index 4496dd928..d33c4a63a 100644
--- a/runtime/org.eclipse.etrice.runtime.java/src/org/eclipse/etrice/runtime/java/messaging/MessageSeQueue.java
+++ b/runtime/org.eclipse.etrice.runtime.java/src/org/eclipse/etrice/runtime/java/messaging/MessageSeQueue.java
@@ -74,8 +74,12 @@ public class MessageSeQueue extends RTObject{
 		return last;
 	}
 	
+	public boolean isEmpty() {
+		return last == null;
+	}
+	
 	public boolean isNotEmpty(){
-		return last != null;
+		return !isEmpty();
 	}
 
 	public long getHightWaterMark() {
diff --git a/runtime/org.eclipse.etrice.runtime.java/src/org/eclipse/etrice/runtime/java/messaging/MessageService.java b/runtime/org.eclipse.etrice.runtime.java/src/org/eclipse/etrice/runtime/java/messaging/MessageService.java
index 84a9bf98c..d8b5b58e1 100644
--- a/runtime/org.eclipse.etrice.runtime.java/src/org/eclipse/etrice/runtime/java/messaging/MessageService.java
+++ b/runtime/org.eclipse.etrice.runtime.java/src/org/eclipse/etrice/runtime/java/messaging/MessageService.java
@@ -70,34 +70,33 @@ public class MessageService extends AbstractMessageService {
 	public void run() {
 		running = true;
 
-		if(pollingScheduler != null)
+		if(pollingScheduler != null) {
 			pollingScheduler.scheduleAtFixedRate(new PollingTask(), pollingInterval, pollingInterval, TimeUnit.NANOSECONDS);
+		}
 
-		while (running) {
+		while(true) {
 			Message msg = null;
-
-			// get next Message from Queue
+			
 			synchronized(this) {
-				msg = getMessageQueue().pop();
-			}
-
-			if (msg == null) {
-				// no message in queue -> wait until Thread is notified
-				try {
-					synchronized(this) {
-						if (!running)
-							return;
+				while(getMessageQueue().isEmpty() && running) {
+					// no message in queue -> wait until Thread is notified
+					try {
 						wait();
 					}
+					catch (InterruptedException e) {}
 				}
-				catch (InterruptedException e) {
+				if(!running) {
+					return;
+				}
+				else {
+					// get next Message from Queue
+					msg = getMessageQueue().pop();
 				}
 			}
-			else {
-				// process message
-				lastMessageTimestamp = System.currentTimeMillis();
-				getMessageDispatcher().receive(msg);
-			}
+			
+			// process message
+			lastMessageTimestamp = System.currentTimeMillis();
+			getMessageDispatcher().receive(msg);
 		}
 	}
 
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