svn commit: r1390680 - in /hadoop/common/branches/branch-2/hadoop-common-project/hadoop-common: CHANGES.txt src/main/java/org/apache/hadoop/io/WritableComparator.java

[bobby]

Author: bobby
Date: Wed Sep 26 19:10:40 2012
New Revision: 1390680

URL: http://svn.apache.org/viewvc?rev=1390680&view=rev
Log:
svn merge -c 1379506 FIXES: HADOOP-8684. Deadlock between WritableComparator 
and WritableComparable. Contributed by Jing Zhao

Modified:
    
hadoop/common/branches/branch-2/hadoop-common-project/hadoop-common/CHANGES.txt
    
hadoop/common/branches/branch-2/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/WritableComparator.java

Modified: 
hadoop/common/branches/branch-2/hadoop-common-project/hadoop-common/CHANGES.txt
URL: 
http://svn.apache.org/viewvc/hadoop/common/branches/branch-2/hadoop-common-project/hadoop-common/CHANGES.txt?rev=1390680&r1=1390679&r2=1390680&view=diff
==============================================================================
--- 
hadoop/common/branches/branch-2/hadoop-common-project/hadoop-common/CHANGES.txt 
(original)
+++ 
hadoop/common/branches/branch-2/hadoop-common-project/hadoop-common/CHANGES.txt 
Wed Sep 26 19:10:40 2012
@@ -750,6 +750,9 @@ Release 0.23.4 - UNRELEASED
     HADOOP-8843. Old trash directories are never deleted on upgrade
     from 1.x (jlowe)
 
+    HADOOP-8684. Deadlock between WritableComparator and WritableComparable.
+    (Jing Zhao via suresh)
+
 Release 0.23.3 - UNRELEASED
 
   INCOMPATIBLE CHANGES

Modified: 
hadoop/common/branches/branch-2/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/WritableComparator.java
URL: 
http://svn.apache.org/viewvc/hadoop/common/branches/branch-2/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/WritableComparator.java?rev=1390680&r1=1390679&r2=1390680&view=diff
==============================================================================
--- 
hadoop/common/branches/branch-2/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/WritableComparator.java
 (original)
+++ 
hadoop/common/branches/branch-2/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/WritableComparator.java
 Wed Sep 26 19:10:40 2012
@@ -18,8 +18,9 @@
 
 package org.apache.hadoop.io;
 
-import java.io.*;
-import java.util.*;
+import java.io.DataInput;
+import java.io.IOException;
+import java.util.concurrent.ConcurrentHashMap;
 
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.classification.InterfaceStability;
@@ -38,12 +39,11 @@ import org.apache.hadoop.util.Reflection
 @InterfaceStability.Stable
 public class WritableComparator implements RawComparator {
 
-  private static HashMap<Class, WritableComparator> comparators =
-    new HashMap<Class, WritableComparator>(); // registry
+  private static final ConcurrentHashMap<Class, WritableComparator> 
comparators 
+          = new ConcurrentHashMap<Class, WritableComparator>(); // registry
 
   /** Get a comparator for a {@link WritableComparable} implementation. */
-  public static synchronized 
-  WritableComparator get(Class<? extends WritableComparable> c) {
+  public static WritableComparator get(Class<? extends WritableComparable> c) {
     WritableComparator comparator = comparators.get(c);
     if (comparator == null) {
       // force the static initializers to run
@@ -76,12 +76,10 @@ public class WritableComparator implemen
   /** Register an optimized comparator for a {@link WritableComparable}
    * implementation. Comparators registered with this method must be
    * thread-safe. */
-  public static synchronized void define(Class c,
-                                         WritableComparator comparator) {
+  public static void define(Class c, WritableComparator comparator) {
     comparators.put(c, comparator);
   }
 
-
   private final Class<? extends WritableComparable> keyClass;
   private final WritableComparable key1;
   private final WritableComparable key2;