From 8a0157a506997d8be5b2fd371ab5019b76e45992 Mon Sep 17 00:00:00 2001
From: James Strachan <jstrachan@apache.org>
Date: Tue, 26 Jun 2007 13:06:32 +0000
Subject: [PATCH] added better synchronization

git-svn-id: https://svn.apache.org/repos/asf/activemq/trunk@550797 13f79535-47bb-0310-9956-ffa450edef68
---
 .../java/org/apache/activemq/memory/UsageManager.java  | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/activemq-core/src/main/java/org/apache/activemq/memory/UsageManager.java b/activemq-core/src/main/java/org/apache/activemq/memory/UsageManager.java
index beb99a60d6..9b7f3d85c8 100755
--- a/activemq-core/src/main/java/org/apache/activemq/memory/UsageManager.java
+++ b/activemq-core/src/main/java/org/apache/activemq/memory/UsageManager.java
@@ -307,10 +307,12 @@ public class UsageManager  implements Service{
     }
     
     private void setPercentUsage(int value) {
-        int oldValue = percentUsage;
-        percentUsage = value;
-        if( oldValue!=value ) {
-            fireEvent(oldValue, value);
+        synchronized (usageMutex) {
+            int oldValue = percentUsage;
+            percentUsage = value;
+            if( oldValue!=value ) {
+                fireEvent(oldValue, value);
+            }
         }
     }