From 14bd82872dac0a7b6de487b1c71a332dabfe4243 Mon Sep 17 00:00:00 2001
From: Michael Stack <stack@apache.org>
Date: Thu, 9 Jun 2011 22:34:32 +0000
Subject: [PATCH] HBASE-3871 Compression.java uses
 ClassLoader.getSystemClassLoader() to load codec

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1134119 13f79535-47bb-0310-9956-ffa450edef68
---
 CHANGES.txt                                   |  2 ++
 .../hadoop/hbase/io/hfile/Compression.java    | 22 +++++++++++++++++--
 2 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/CHANGES.txt b/CHANGES.txt
index ec60c012b0b..2c27d24a3b1 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -115,6 +115,8 @@ Release 0.91.0 - Unreleased
    HBASE-3894  Thread contention over row locks set monitor (Dave Latham)
    HBASE-3959  hadoop-snappy version in the pom.xml is incorrect
                (Alejandro Abdelnur)
+   HBASE-3971  Compression.java uses ClassLoader.getSystemClassLoader()
+               to load codec (Alejandro Abdelnur)
 
   IMPROVEMENTS
    HBASE-3290  Max Compaction Size (Nicolas Spiegelberg via Stack)  
diff --git a/src/main/java/org/apache/hadoop/hbase/io/hfile/Compression.java b/src/main/java/org/apache/hadoop/hbase/io/hfile/Compression.java
index 4d04b66eba8..c0de5fc07e8 100644
--- a/src/main/java/org/apache/hadoop/hbase/io/hfile/Compression.java
+++ b/src/main/java/org/apache/hadoop/hbase/io/hfile/Compression.java
@@ -70,6 +70,24 @@ public final class Compression {
     }
   }
 
+  /**
+   * Returns the classloader to load the Codec class from.
+   * @return
+   */
+  private static ClassLoader getClassLoaderForCodec() {
+    ClassLoader cl = Thread.currentThread().getContextClassLoader();
+    if (cl == null) {
+      cl = Compression.class.getClassLoader();
+    }
+    if (cl == null) {
+      cl = ClassLoader.getSystemClassLoader();
+    }
+    if (cl == null) {
+      throw new RuntimeException("A ClassLoader to load the Codec could not be determined");
+    }
+    return cl;
+  }
+
   /**
    * Compression algorithms. The ordinal of these cannot change or else you
    * risk breaking all existing HFiles out there.  Even the ones that are
@@ -85,7 +103,7 @@ public final class Compression {
         if (lzoCodec == null) {
           try {
             Class<?> externalCodec =
-                ClassLoader.getSystemClassLoader().loadClass("com.hadoop.compression.lzo.LzoCodec");
+                getClassLoaderForCodec().loadClass("com.hadoop.compression.lzo.LzoCodec");
             lzoCodec = (CompressionCodec) ReflectionUtils.newInstance(externalCodec, 
                 new Configuration(conf));
           } catch (ClassNotFoundException e) {
@@ -150,7 +168,7 @@ public final class Compression {
           if (snappyCodec == null) {
             try {
               Class<?> externalCodec =
-                  ClassLoader.getSystemClassLoader().loadClass("org.apache.hadoop.io.compress.SnappyCodec");
+                  getClassLoaderForCodec().loadClass("org.apache.hadoop.io.compress.SnappyCodec");
               snappyCodec = (CompressionCodec) ReflectionUtils.newInstance(externalCodec, 
                   conf);
             } catch (ClassNotFoundException e) {