From 822ef8b38a63e3b351b30c382bfc77de39904c77 Mon Sep 17 00:00:00 2001
From: Robert Godfrey <rgodfrey@apache.org>
Date: Thu, 12 Feb 2015 17:57:11 +0000
Subject: QPID-6374 : avoid taking a lock when not modifying a value

git-svn-id: https://svn.apache.org/repos/asf/qpid/trunk@1659341 13f79535-47bb-0310-9956-ffa450edef68
---
 .../java/org/apache/qpid/client/AMQSession.java    | 27 ++++++++++++----------
 1 file changed, 15 insertions(+), 12 deletions(-)

(limited to 'qpid/java/client/src')

diff --git a/qpid/java/client/src/main/java/org/apache/qpid/client/AMQSession.java b/qpid/java/client/src/main/java/org/apache/qpid/client/AMQSession.java
index 86e1bb0a8b..8f5e9524b6 100644
--- a/qpid/java/client/src/main/java/org/apache/qpid/client/AMQSession.java
+++ b/qpid/java/client/src/main/java/org/apache/qpid/client/AMQSession.java
@@ -224,7 +224,7 @@ public abstract class AMQSession<C extends BasicMessageConsumer, P extends Basic
     private volatile boolean _usingDispatcherForCleanup;
 
     /** Used to indicates that the connection to which this session belongs, has been stopped. */
-    private boolean _connectionStopped;
+    private final AtomicBoolean _connectionStopped = new AtomicBoolean();
 
     /** Used to indicate that this session has a message listener attached to it. */
     private boolean _hasMessageListeners;
@@ -3410,25 +3410,28 @@ public abstract class AMQSession<C extends BasicMessageConsumer, P extends Basic
         // only call while holding lock
         final boolean connectionStopped()
         {
-            return _connectionStopped;
+            return _connectionStopped.get();
         }
 
         boolean setConnectionStopped(boolean connectionStopped)
         {
-            boolean currently;
-            synchronized (_lock)
+            boolean currently = _connectionStopped.get();
+            if(connectionStopped != currently)
             {
-                currently = _connectionStopped;
-                _connectionStopped = connectionStopped;
-                _lock.notify();
-
-                if (_dispatcherLogger.isDebugEnabled())
+                synchronized (_lock)
                 {
-                    _dispatcherLogger.debug("Set Dispatcher Connection " + (connectionStopped ? "Stopped" : "Started")
-                                            + ": Currently " + (currently ? "Stopped" : "Started"));
+                    _connectionStopped.set(connectionStopped);
+                    _lock.notify();
+
+                    if (_dispatcherLogger.isDebugEnabled())
+                    {
+                        _dispatcherLogger.debug("Set Dispatcher Connection " + (connectionStopped
+                                ? "Stopped"
+                                : "Started")
+                                                + ": Currently " + (currently ? "Stopped" : "Started"));
+                    }
                 }
             }
-
             return currently;
         }
 
-- 
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