From 9a66fe79df826ba787ce85df6393d2794c460576 Mon Sep 17 00:00:00 2001
From: Zhihong Yu <tedyu@apache.org>
Date: Wed, 31 Aug 2011 03:05:05 +0000
Subject: [PATCH] HBASE-4307  race condition in CacheTestUtils (Li Pi)

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1163476 13f79535-47bb-0310-9956-ffa450edef68
---
 CHANGES.txt                                                | 1 +
 .../org/apache/hadoop/hbase/io/hfile/CacheTestUtils.java   | 7 ++++++-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/CHANGES.txt b/CHANGES.txt
index d7cf0f51911..a07196c7ff5 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -227,6 +227,7 @@ Release 0.91.0 - Unreleased
    HBASE-4290  HLogSplitter doesn't mark its MonitoredTask as complete in
                non-distributed case (todd)
    HBASE-4303  HRegionInfo.toString has bad quoting (todd)
+   HBASE-4307  race condition in CacheTestUtils (Li Pi)
 
   IMPROVEMENTS
    HBASE-3290  Max Compaction Size (Nicolas Spiegelberg via Stack)  
diff --git a/src/test/java/org/apache/hadoop/hbase/io/hfile/CacheTestUtils.java b/src/test/java/org/apache/hadoop/hbase/io/hfile/CacheTestUtils.java
index 895a9fe7780..ed315039f0a 100644
--- a/src/test/java/org/apache/hadoop/hbase/io/hfile/CacheTestUtils.java
+++ b/src/test/java/org/apache/hadoop/hbase/io/hfile/CacheTestUtils.java
@@ -56,7 +56,12 @@ public class CacheTestUtils {
         @Override
         public void doAnAction() throws Exception {
           if (!blocksToTest.isEmpty()) {
-            HFileBlockPair ourBlock = blocksToTest.remove();
+            HFileBlockPair ourBlock = blocksToTest.poll();
+            //if we run out of blocks to test, then we should stop the tests.
+            if(ourBlock == null){
+              ctx.stop();
+              return;
+            }
             toBeTested.cacheBlock(ourBlock.blockName, ourBlock.block);
             Cacheable retrievedBlock = toBeTested.getBlock(ourBlock.blockName,
                 false);