[Bigdata-commit] SF.net SVN: bigdata:[4282] branches/QUADS_QUERY_BRANCH/bigdata/src/java/com /bigdata

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

Revision: 4282
          http://bigdata.svn.sourceforge.net/bigdata/?rev=4282&view=rev
Author:   thompsonbry
Date:     2011-03-08 15:15:03 +0000 (Tue, 08 Mar 2011)

Log Message:
-----------
Javadoc edit to RWStore's reopen.
A

Modified Paths:
--------------
    branches/QUADS_QUERY_BRANCH/bigdata/src/java/com/bigdata/journal/WORMStrategy.java
    branches/QUADS_QUERY_BRANCH/bigdata/src/java/com/bigdata/rwstore/RWStore.java

Modified: branches/QUADS_QUERY_BRANCH/bigdata/src/java/com/bigdata/journal/WORMStrategy.java
===================================================================
--- branches/QUADS_QUERY_BRANCH/bigdata/src/java/com/bigdata/journal/WORMStrategy.java	2011-03-08 15:12:43 UTC (rev 4281)
+++ branches/QUADS_QUERY_BRANCH/bigdata/src/java/com/bigdata/journal/WORMStrategy.java	2011-03-08 15:15:03 UTC (rev 4282)
@@ -1426,8 +1426,24 @@
      */
     private FileChannel reopenChannel() throws IOException {
 
-        synchronized (opener) {
+		/*
+		 * Note: This is basically a double-checked locking pattern. It is
+		 * used to avoid synchronizing when the backing channel is already
+		 * open.
+		 */
+		{
+			final RandomAccessFile tmp = raf;
+			if (tmp != null) {
+				final FileChannel channel = tmp.getChannel();
+				if (channel.isOpen()) {
+					// The channel is still open.
+					return channel;
+				}
+			}
+		}
 
+		synchronized (opener) {
+
             assertOpen();
 
             if (raf != null && raf.getChannel().isOpen()) {

Modified: branches/QUADS_QUERY_BRANCH/bigdata/src/java/com/bigdata/rwstore/RWStore.java
===================================================================
--- branches/QUADS_QUERY_BRANCH/bigdata/src/java/com/bigdata/rwstore/RWStore.java	2011-03-08 15:12:43 UTC (rev 4281)
+++ branches/QUADS_QUERY_BRANCH/bigdata/src/java/com/bigdata/rwstore/RWStore.java	2011-03-08 15:15:03 UTC (rev 4282)
@@ -3149,14 +3149,7 @@
 				if (tmp != null) {
 					final FileChannel channel = tmp.getChannel();
 					if (channel.isOpen()) {
-						/*
-						 * The channel is still open. If you are allowing
-						 * concurrent reads on the channel, then this could
-						 * indicate that two readers each found the channel
-						 * closed and that one was able to re-open the channel
-						 * before the other such that the channel was open again
-						 * by the time the 2nd reader got here.
-						 */
+						// The channel is still open.
 						return channel;
 					}
 				}
@@ -3167,6 +3160,14 @@
 				if (raf != null) {
 					final FileChannel channel = raf.getChannel();
 					if (channel.isOpen()) {
+						/*
+						 * The channel is still open. If you are allowing
+						 * concurrent reads on the channel, then this could
+						 * indicate that two readers each found the channel
+						 * closed and that one was able to re-open the channel
+						 * before the other such that the channel was open again
+						 * by the time the 2nd reader got here.
+						 */
 						return channel;
 					}
 				}


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