[Bigdata-commit] SF.net SVN: bigdata:[7099] branches/READ_CACHE/bigdata/src/java/com/bigdata /journal/WORMStrategy.java

[<tho...@us...>]

Revision: 7099
          http://bigdata.svn.sourceforge.net/bigdata/?rev=7099&view=rev
Author:   thompsonbry
Date:     2013-05-03 12:11:49 +0000 (Fri, 03 May 2013)
Log Message:
-----------
javadoc on the extensionLock in the WORMStrategy.

Modified Paths:
--------------
    branches/READ_CACHE/bigdata/src/java/com/bigdata/journal/WORMStrategy.java

Modified: branches/READ_CACHE/bigdata/src/java/com/bigdata/journal/WORMStrategy.java
===================================================================
--- branches/READ_CACHE/bigdata/src/java/com/bigdata/journal/WORMStrategy.java	2013-05-02 20:56:56 UTC (rev 7098)
+++ branches/READ_CACHE/bigdata/src/java/com/bigdata/journal/WORMStrategy.java	2013-05-03 12:11:49 UTC (rev 7099)
@@ -39,6 +39,8 @@
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.concurrent.locks.Lock;
 import java.util.concurrent.locks.ReentrantReadWriteLock;
+import java.util.concurrent.locks.ReentrantReadWriteLock.ReadLock;
+import java.util.concurrent.locks.ReentrantReadWriteLock.WriteLock;
 
 import com.bigdata.LRUNexus;
 import com.bigdata.btree.BTree.Counter;
@@ -192,9 +194,11 @@
 //    private final AtomicReference<Quorum<?,?>> quorumRef;
 
     /**
-     * This lock is used to exclude readers when the extent of the backing file
-     * is about to be changed. This is a workaround for an old (an unresolved as
-     * of February 2010) Sun bug.
+     * This lock is used to exclude readers/writers performing IOs against the
+     * backing file when the extent of the backing file is about to be changed.
+     * Readers and writers take the {@link ReadLock}. The {@link WriteLock} is
+     * taken when the file extent must be changed. This is a workaround for an
+     * old (an unresolved as of February 2010) Sun bug.
      * 
      * @see http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6371642
      */

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