HDFS-3482. Merging r1358812 from trunk to branch-2

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1614814 13f79535-47bb-0310-9956-ffa450edef68

hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

@@ -146,6 +146,9 @@ Release 2.6.0 - UNRELEASED
     XmlEditsVisitor.java is JVM vendor specific. Breaks IBM JAVA.
     (Amir Sanjar via stevel)
 
+    HDFS-3482. hdfs balancer throws ArrayIndexOutOfBoundsException 
+    if option is specified without values. ( Madhukara Phatak via umamahesh) 
+
 Release 2.5.0 - UNRELEASED
 
   INCOMPATIBLE CHANGES

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/balancer/Balancer.java

@@ -87,6 +87,7 @@ import org.apache.hadoop.util.StringUtils;
 import org.apache.hadoop.util.Time;
 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.
@@ -1584,6 +1585,7 @@ public class Balancer {
       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 {

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/balancer/TestBalancer.java

@@ -538,6 +538,39 @@ public class TestBalancer {
     oneNodeTest(conf, true);
   }
   
+  /**
+   * 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
    */