Re: svn commit: r608235 - /cayenne/main/trunk/framework/cayenne-jdk1.5-unpublished/src/main/java/org/apache/cayenne/access/DataContext.java

[Andrus Adamchik]

Also I think the article quoted predates java 5 which (I think) makes  
double checked locking safe for "volatile" ivars??

Andrus
On Jan 2, 2008, at 11:51 PM, Tore Halset wrote:

Hello.

Interesting. Is it possible to use the "Making it work for static  
singletons" variant to get rid of the synchronization?

Btw, this is also very well described in "Effective Java Programming  
Language guide" by Joshua Bloch - a must-have book for me.

- Tore.

On Jan 2, 2008, at 22:26, [EMAIL PROTECTED] wrote:

Author: mgentry
Date: Wed Jan  2 13:26:15 2008
New Revision: 608235

URL: http://svn.apache.org/viewvc?rev=608235&view=rev
Log:
Removed double-checked locking of queryCache.  See http://www.cs.umd.edu/~pugh/java/memoryModel/DoubleCheckedLocking.html 
 for details.

Modified:
  cayenne/main/trunk/framework/cayenne-jdk1.5-unpublished/src/main/ 
java/org/apache/cayenne/access/DataContext.java

Modified: cayenne/main/trunk/framework/cayenne-jdk1.5-unpublished/ 
src/main/java/org/apache/cayenne/access/DataContext.java
URL: 
http://svn.apache.org/viewvc/cayenne/main/trunk/framework/cayenne-jdk1.5-unpublished/src/main/java/org/apache/cayenne/access/DataContext.java?rev=608235&r1=608234&r2=608235&view=diff
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=====================================================================
--- cayenne/main/trunk/framework/cayenne-jdk1.5-unpublished/src/ 
main/java/org/apache/cayenne/access/DataContext.java (original)
+++ cayenne/main/trunk/framework/cayenne-jdk1.5-unpublished/src/ 
main/java/org/apache/cayenne/access/DataContext.java Wed Jan  2  
13:26:15 2008
@@ -257,16 +257,11 @@
    *
    * @since 3.0
    */
-    public QueryCache getQueryCache() {
-
+    public synchronized QueryCache getQueryCache() {
       if (queryCache == null) {
-            synchronized (this) {
-                if (queryCache == null) {
-                    queryCache = getParentDataDomain()
-                            .getQueryCacheFactory()
-                            .getQueryCache(Collections.EMPTY_MAP);
-                }
-            }
+            queryCache = getParentDataDomain()
+                    .getQueryCacheFactory()
+                    .getQueryCache(Collections.EMPTY_MAP);
       }

       return queryCache;
@@ -277,7 +272,7 @@
    *
    * @since 3.0
    */
-    public void setQueryCache(QueryCache queryCache) {
+    public synchronized void setQueryCache(QueryCache queryCache) {
       this.queryCache = queryCache;
   }