From 07295260b10cd2376660a673ceb9d8ce0570b528 Mon Sep 17 00:00:00 2001
From: Uma Maheswara Rao G <umamahesh@apache.org>
Date: Sun, 8 Jul 2012 18:39:09 +0000
Subject: [PATCH] HDFS-3482. hdfs balancer throws
 ArrayIndexOutOfBoundsException if option is specified without values.
 Contributed by Madhukara Phatak.

Submitted by:	Madhukara Phatak.
Reviewed by:	Uma Maheswara Rao G.


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1358812 13f79535-47bb-0310-9956-ffa450edef68
---
 hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt   |  3 ++
 .../hadoop/hdfs/server/balancer/Balancer.java |  2 ++
 .../hdfs/server/balancer/TestBalancer.java    | 33 +++++++++++++++++++
 3 files changed, 38 insertions(+)

diff --git a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
index 94f6d9a71f..4b47924caf 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
+++ b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
@@ -177,6 +177,9 @@ Trunk (unreleased changes)
 
     HDFS-3541. Deadlock between recovery, xceiver and packet responder (Vinay via umamahesh)
 
+    HDFS-3482. hdfs balancer throws ArrayIndexOutOfBoundsException 
+    if option is specified without values. ( Madhukara Phatak via umamahesh) 
+
 Branch-2 ( Unreleased changes )
 
   INCOMPATIBLE CHANGES
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/balancer/Balancer.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/balancer/Balancer.java
index 0576f895c3..e38320e7b0 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/balancer/Balancer.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/balancer/Balancer.java
@@ -74,6 +74,7 @@
 import org.apache.hadoop.util.StringUtils;
 import org.apache.hadoop.util.Tool;
 import org.apache.hadoop.util.ToolRunner;
+import static com.google.common.base.Preconditions.checkArgument;
 
 /** <p>The balancer is a tool that balances disk space usage on an HDFS cluster
  * when some datanodes become full or when new empty nodes join the cluster.
@@ -1501,6 +1502,7 @@ static Parameters parse(String[] args) {
       if (args != null) {
         try {
           for(int i = 0; i < args.length; i++) {
+            checkArgument(args.length >= 2, "args = " + Arrays.toString(args));           
             if ("-threshold".equalsIgnoreCase(args[i])) {
               i++;
               try {
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/balancer/TestBalancer.java b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/balancer/TestBalancer.java
index 11dbfc89e0..8f1077e73e 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/balancer/TestBalancer.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/balancer/TestBalancer.java
@@ -453,6 +453,39 @@ private void testBalancerDefaultConstructor(Configuration conf,
     }
   }
 
+  /**
+   * Test parse method in Balancer#Cli class with wrong number of params
+   */
+
+  @Test
+  public void testBalancerCliParseWithWrongParams() {
+    String parameters[] = new String[] { "-threshold" };
+    String reason =
+        "IllegalArgumentException is expected when value is not specified";
+    try {
+      Balancer.Cli.parse(parameters);
+      fail(reason);
+    } catch (IllegalArgumentException e) {
+
+    }
+    parameters = new String[] { "-policy" };
+    try {
+      Balancer.Cli.parse(parameters);
+      fail(reason);
+    } catch (IllegalArgumentException e) {
+
+    }
+    parameters = new String[] { "-threshold 1 -policy" };
+    try {
+      Balancer.Cli.parse(parameters);
+      fail(reason);
+    } catch (IllegalArgumentException e) {
+
+    }
+
+  }
+
+
   /**
    * @param args
    */