HADOOP-6004. Fixes BlockLocation deserialization. Contributed by Jakob Homan

git-svn-id: https://svn.apache.org/repos/asf/hadoop/core/trunk@786264 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -838,6 +838,9 @@ Trunk (unreleased changes)
     HADOOP-6076. Fix a broken compilation of Forrest documentation due to
     misplaced tags in commands_manual.xml. (yhemanth)
 
+    HADOOP-6004. Fixes BlockLocation deserialization.  (Jakob Homan via
+    szetszwo)
+
 Release 0.20.1 - Unreleased
 
   INCOMPATIBLE CHANGES
@@ -935,9 +938,6 @@ Release 0.20.1 - Unreleased
     available memory on a tasktracker.
     (Vinod Kumar Vavilapalli via yhemanth)
 
-    HADOOP-5937. Correct a safemode message in FSNamesystem.  (Ravi Phulari
-    via szetszwo)
-
     HADOOP-5908. Fixes a problem to do with ArithmeticException in the 
     JobTracker when there are jobs with 0 maps. (Amar Kamat via ddas)
 
@@ -956,6 +956,9 @@ Release 0.20.1 - Unreleased
     HADOOP-5884. Fixes accounting in capacity scheduler so that high RAM jobs
     take more slots. (Vinod Kumar Vavilapalli via yhemanth)
 
+    HADOOP-5937. Correct a safemode message in FSNamesystem.  (Ravi Phulari
+    via szetszwo)
+
     HADOOP-5869. Fix bug in assignment of setup / cleanup task that was
     causing TestQueueCapacities to fail.
     (Sreekanth Ramakrishnan via yhemanth)

src/core/org/apache/hadoop/fs/BlockLocation.java

@@ -17,9 +17,14 @@
  */
 package org.apache.hadoop.fs;
 
-import org.apache.hadoop.io.*;
+import java.io.DataInput;
+import java.io.DataOutput;
+import java.io.IOException;
 
-import java.io.*;
+import org.apache.hadoop.io.Text;
+import org.apache.hadoop.io.Writable;
+import org.apache.hadoop.io.WritableFactories;
+import org.apache.hadoop.io.WritableFactory;
 
 /*
  * A BlockLocation lists hosts, offset and length
@@ -213,15 +218,19 @@ public class BlockLocation implements Writable {
       name.readFields(in);
       names[i] = name.toString();
     }
+    
     int numHosts = in.readInt();
+    this.hosts = new String[numHosts];
     for (int i = 0; i < numHosts; i++) {
       Text host = new Text();
       host.readFields(in);
       hosts[i] = host.toString();
     }
+    
     int numTops = in.readInt();
-    Text path = new Text();
+    topologyPaths = new String[numTops];
     for (int i = 0; i < numTops; i++) {
+      Text path = new Text();
       path.readFields(in);
       topologyPaths[i] = path.toString();
     }

src/test/core/org/apache/hadoop/fs/TestBlockLocation.java

@@ -0,0 +1,78 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.fs;
+
+import java.io.ByteArrayInputStream;
+import java.io.DataInput;
+import java.io.DataInputStream;
+import java.io.IOException;
+
+import junit.framework.TestCase;
+
+import org.apache.hadoop.io.DataOutputBuffer;
+
+public class TestBlockLocation extends TestCase {
+  // Verify fix of bug identified in HADOOP-6004
+  public void testDeserialization() throws IOException {
+    // Create a test BlockLocation
+    String[] names = {"one", "two" };
+    String[] hosts = {"three", "four" };
+    String[] topologyPaths = {"five", "six"};
+    long offset = 25l;
+    long length = 55l;
+    
+    BlockLocation bl = new BlockLocation(names, hosts, topologyPaths, 
+                                         offset, length);
+    
+    DataOutputBuffer dob = new DataOutputBuffer();
+    
+    // Serialize it
+    try {
+      bl.write(dob);
+    } catch (IOException e) {
+      fail("Unable to serialize data: " + e.getMessage());
+    }
+
+    byte[] bytes = dob.getData();
+    DataInput da = new DataInputStream(new ByteArrayInputStream(bytes));
+
+    // Try to re-create the BlockLocation the same way as is done during
+    // deserialization
+    BlockLocation bl2 = new BlockLocation();
+    
+    try {
+      bl2.readFields(da);
+    } catch (IOException e) {
+      fail("Unable to deserialize BlockLocation: " + e.getMessage());
+    }
+    
+    // Check that we got back what we started with
+    verifyDeserialization(bl2.getHosts(), hosts);
+    verifyDeserialization(bl2.getNames(), names);
+    verifyDeserialization(bl2.getTopologyPaths(), topologyPaths);
+    assertEquals(bl2.getOffset(), offset);
+    assertEquals(bl2.getLength(), length);
+  }
+
+  private void verifyDeserialization(String[] ar1, String[] ar2) {
+    assertEquals(ar1.length, ar2.length);
+    
+    for(int i = 0; i < ar1.length; i++)
+      assertEquals(ar1[i], ar2[i]);
+  }
+}