MAPREDUCE-465. Fix a bug in MultithreadedMapRunner. Contributed by Amareshwari Sriramadasu.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-0.20@794218 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -178,6 +178,9 @@ Release 0.20.1 - Unreleased
     MAPREDUCE-565. Fix partitioner to work with new API. (Owen O'Malley via
     cdouglas)
 
+    MAPREDUCE-465. Fix a bug in MultithreadedMapRunner. (Amareshwari 
+    Sriramadasu via sharad)
+
 Release 0.20.0 - 2009-04-15
 
   INCOMPATIBLE CHANGES

src/mapred/org/apache/hadoop/mapreduce/lib/map/MultithreadedMapper.java

@@ -56,7 +56,7 @@ public class MultithreadedMapper<K1, V1, K2, V2>
   extends Mapper<K1, V1, K2, V2> {
 
   private static final Log LOG = LogFactory.getLog(MultithreadedMapper.class);
-  private Class<Mapper<K1,V1,K2,V2>> mapClass;
+  private Class<? extends Mapper<K1,V1,K2,V2>> mapClass;
   private Context outer;
   private List<MapRunner> runners;
 
@@ -108,7 +108,7 @@ public class MultithreadedMapper<K1, V1, K2, V2>
    */
   public static <K1,V1,K2,V2> 
   void setMapperClass(Job job, 
-                      Class<Mapper<K1,V1,K2,V2>> cls) {
+                      Class<? extends Mapper<K1,V1,K2,V2>> cls) {
     if (MultithreadedMapper.class.isAssignableFrom(cls)) {
       throw new IllegalArgumentException("Can't have recursive " + 
                                          "MultithreadedMapper instances.");
@@ -134,7 +134,7 @@ public class MultithreadedMapper<K1, V1, K2, V2>
     for(int i=0; i < numberOfThreads; ++i) {
       MapRunner thread = new MapRunner(context);
       thread.start();
-      runners.set(i, thread);
+      runners.add(i, thread);
     }
     for(int i=0; i < numberOfThreads; ++i) {
       MapRunner thread = runners.get(i);

src/test/org/apache/hadoop/mapreduce/lib/map/TestMultithreadedMapper.java

@@ -0,0 +1,123 @@
+/**
+ * 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.mapreduce.lib.map;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.FileSystem;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.io.LongWritable;
+import org.apache.hadoop.io.Text;
+import org.apache.hadoop.mapred.HadoopTestCase;
+import org.apache.hadoop.mapreduce.*;
+import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
+import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
+
+import java.io.DataOutputStream;
+import java.io.IOException;
+
+public class TestMultithreadedMapper extends HadoopTestCase {
+
+  public TestMultithreadedMapper() throws IOException {
+    super(HadoopTestCase.LOCAL_MR, HadoopTestCase.LOCAL_FS, 1, 1);
+  }
+
+  public void testOKRun() throws Exception {
+    run(false, false);
+  }
+
+  public void testIOExRun() throws Exception {
+    run(true, false);
+  }
+  public void testRuntimeExRun() throws Exception {
+    run(false, true);
+  }
+
+  private void run(boolean ioEx, boolean rtEx) throws Exception {
+    String localPathRoot = System.getProperty("test.build.data", "/tmp");
+    Path inDir = new Path(localPathRoot, "testing/mt/input");
+    Path outDir = new Path(localPathRoot, "testing/mt/output");
+
+
+    Configuration conf = createJobConf();
+    if (ioEx) {
+      conf.setBoolean("multithreaded.ioException", true);
+    }
+    if (rtEx) {
+      conf.setBoolean("multithreaded.runtimeException", true);
+    }
+
+    Job job = new Job(conf);
+    FileSystem fs = FileSystem.get(conf);
+    if (fs.exists(outDir)) {
+      fs.delete(outDir, true);
+    }
+    if (fs.exists(inDir)) {
+      fs.delete(inDir, true);
+    }
+    fs.mkdirs(inDir);
+    String input = "The quick brown fox\n" + "has many silly\n"
+      + "red fox sox\n";
+    DataOutputStream file = fs.create(new Path(inDir, "part-" + 0));
+    file.writeBytes(input);
+    file.close();
+
+    FileInputFormat.setInputPaths(job, inDir);
+    FileOutputFormat.setOutputPath(job, outDir);
+    job.setNumReduceTasks(1);
+    job.setJobName("mt");
+
+    job.setMapperClass(MultithreadedMapper.class);
+    MultithreadedMapper.setMapperClass(job, IDMap.class);
+    MultithreadedMapper.setNumberOfThreads(job, 2);
+    job.setReducerClass(Reducer.class);
+
+    job.waitForCompletion(true);
+
+    if (job.isSuccessful()) {
+      assertFalse(ioEx || rtEx);
+    }
+    else {
+      assertTrue(ioEx || rtEx);
+    }
+  }
+
+  public static class IDMap extends 
+      Mapper<LongWritable, Text, LongWritable, Text> {
+    private boolean ioEx = false;
+    private boolean rtEx = false;
+
+    public void setup(Context context) {
+      ioEx = context.getConfiguration().
+               getBoolean("multithreaded.ioException", false);
+      rtEx = context.getConfiguration().
+               getBoolean("multithreaded.runtimeException", false);
+    }
+
+    public void map(LongWritable key, Text value, Context context)
+        throws IOException, InterruptedException {
+      if (ioEx) {
+        throw new IOException();
+      }
+      if (rtEx) {
+        throw new RuntimeException();
+      }
+      super.map(key, value, context);
+    }
+  }
+}