Return-Path: Delivered-To: apmail-commons-commits-archive@minotaur.apache.org Received: (qmail 11639 invoked from network); 26 Sep 2009 15:03:30 -0000 Received: from hermes.apache.org (HELO mail.apache.org) (140.211.11.3) by minotaur.apache.org with SMTP; 26 Sep 2009 15:03:30 -0000 Received: (qmail 55235 invoked by uid 500); 26 Sep 2009 15:03:30 -0000 Delivered-To: apmail-commons-commits-archive@commons.apache.org Received: (qmail 55140 invoked by uid 500); 26 Sep 2009 15:03:30 -0000 Mailing-List: contact commits-help@commons.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: dev@commons.apache.org Delivered-To: mailing list commits@commons.apache.org Received: (qmail 55131 invoked by uid 99); 26 Sep 2009 15:03:30 -0000 Received: from nike.apache.org (HELO nike.apache.org) (192.87.106.230) by apache.org (qpsmtpd/0.29) with ESMTP; Sat, 26 Sep 2009 15:03:30 +0000 X-ASF-Spam-Status: No, hits=-2000.0 required=10.0 tests=ALL_TRUSTED X-Spam-Check-By: apache.org Received: from [140.211.11.4] (HELO eris.apache.org) (140.211.11.4) by apache.org (qpsmtpd/0.29) with ESMTP; Sat, 26 Sep 2009 15:03:27 +0000 Received: by eris.apache.org (Postfix, from userid 65534) id 731B92388906; Sat, 26 Sep 2009 15:03:06 +0000 (UTC) Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: svn commit: r819146 - /commons/proper/lang/trunk/src/java/org/apache/commons/lang/concurrent/LazyInitializer.java Date: Sat, 26 Sep 2009 15:03:06 -0000 To: commits@commons.apache.org From: oheger@apache.org X-Mailer: svnmailer-1.0.8 Message-Id: <20090926150306.731B92388906@eris.apache.org> X-Virus-Checked: Checked by ClamAV on apache.org Author: oheger Date: Sat Sep 26 15:03:06 2009 New Revision: 819146 URL: http://svn.apache.org/viewvc?rev=819146&view=rev Log: [LANG-496] Added a comment why a temporary variable is used in get(). Modified: commons/proper/lang/trunk/src/java/org/apache/commons/lang/concurrent/LazyInitializer.java Modified: commons/proper/lang/trunk/src/java/org/apache/commons/lang/concurrent/LazyInitializer.java URL: http://svn.apache.org/viewvc/commons/proper/lang/trunk/src/java/org/apache/commons/lang/concurrent/LazyInitializer.java?rev=819146&r1=819145&r2=819146&view=diff ============================================================================== --- commons/proper/lang/trunk/src/java/org/apache/commons/lang/concurrent/LazyInitializer.java (original) +++ commons/proper/lang/trunk/src/java/org/apache/commons/lang/concurrent/LazyInitializer.java Sat Sep 26 15:03:06 2009 @@ -42,9 +42,11 @@ * to this class, a subclass of {@code LazyInitializer} has to be created: * * 
- * public class ComplexObjectInitializer extends LazyInitializer<ComplexObject> {
+ * public class ComplexObjectInitializer extends LazyInitializer<ComplexObject>
+ * {
  *     @Override
- *     protected ComplexObject initialize() {
+ *     protected ComplexObject initialize()
+ *     {
  *         return new ComplexObject();
  *     }
  * }
@@ -75,7 +77,8 @@
  * @version $Id$
  * @param  the type of the object managed by this initializer class
  */
-public abstract class LazyInitializer {
+public abstract class LazyInitializer
+{
     /** Stores the managed object. */
     private volatile T object;
 
@@ -85,13 +88,19 @@
      *
      * @return the object initialized by this {@code LazyInitializer}
      */
-    public T get() {
+    public T get()
+    {
+        // use a temporary variable to reduce the number of reads of the
+        // volatile field
         T result = object;
 
-        if (result == null) {
-            synchronized (this) {
+        if (result == null)
+        {
+            synchronized (this)
+            {
                 result = object;
-                if (result == null) {
+                if (result == null)
+                {
                     object = result = initialize();
                 }
             }