Merge -c 1241319 from trunk to branch-0.23 to fix MAPREDUCE-3697. Support binary compatibility for Counters after MAPREDUCE-901.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-0.23@1241321 13f79535-47bb-0310-9956-ffa450edef68

hadoop-mapreduce-project/CHANGES.txt

@@ -688,6 +688,9 @@ Release 0.23.1 - Unreleased
     MAPREDUCE-3794. Support mapred.Task.Counter and mapred.JobInProgress.Counter 
     enums for compatibility (Tom White via mahadev)
 
+    MAPREDUCE-3697. Support binary compatibility for Counters after
+    MAPREDUCE-901. (mahadev via acmurthy) 
+
 Release 0.23.0 - 2011-11-01 
 
   INCOMPATIBLE CHANGES

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapred/Counters.java

@@ -21,8 +21,14 @@ package org.apache.hadoop.mapred;
 import static org.apache.hadoop.mapreduce.util.CountersStrings.parseEscapedCompactString;
 import static org.apache.hadoop.mapreduce.util.CountersStrings.toEscapedCompactString;
 
+import java.io.DataInput;
+import java.io.DataOutput;
+import java.io.IOException;
 import java.text.ParseException;
+import java.util.Collection;
+import java.util.Iterator;
 
+import org.apache.commons.collections.IteratorUtils;
 import org.apache.commons.logging.Log;
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.classification.InterfaceStability;
@@ -36,6 +42,9 @@ import org.apache.hadoop.mapreduce.counters.FrameworkCounterGroup;
 import org.apache.hadoop.mapreduce.counters.GenericCounter;
 import org.apache.hadoop.mapreduce.counters.Limits;
 import org.apache.hadoop.mapreduce.lib.input.FileInputFormatCounter;
+import org.apache.hadoop.mapreduce.util.CountersStrings;
+
+import com.google.common.collect.Iterators;
 
 /**
  * A set of named counters.
@@ -51,7 +60,9 @@ import org.apache.hadoop.mapreduce.lib.input.FileInputFormatCounter;
 @InterfaceStability.Stable
 public class Counters
     extends AbstractCounters<Counters.Counter, Counters.Group> {
-
+  
+  public static int MAX_COUNTER_LIMIT = Limits.COUNTERS_MAX;
+  
   public Counters() {
     super(groupFactory);
   }
@@ -69,17 +80,82 @@ public class Counters
     return new Counters(newCounters);
   }
 
+  public synchronized Group getGroup(String groupName) {
+    return super.getGroup(groupName);
+  }
+
+  @SuppressWarnings("unchecked")
+  public synchronized Collection<String> getGroupNames() {
+    return IteratorUtils.toList(super.getGroupNames().iterator());
+  }
+
+  public synchronized String makeCompactString() {
+    return CountersStrings.toEscapedCompactString(this);
+  }
+  
   /**
    * A counter record, comprising its name and value.
    */
-  public interface Counter extends org.apache.hadoop.mapreduce.Counter {
+  public static class Counter implements org.apache.hadoop.mapreduce.Counter {
+    org.apache.hadoop.mapreduce.Counter realCounter;
+
+    Counter(org.apache.hadoop.mapreduce.Counter counter) {
+      this.realCounter = counter;
+    }
+
+    public Counter() {
+      this(new GenericCounter());
+    }
+
+    @SuppressWarnings("deprecation")
+    @Override
+    public void setDisplayName(String displayName) {
+      realCounter.setDisplayName(displayName);
+    }
+
+    @Override
+    public String getName() {
+      return realCounter.getName();
+    }
+
+    @Override
+    public String getDisplayName() {
+      return realCounter.getDisplayName();
+    }
+
+    @Override
+    public long getValue() {
+      return realCounter.getValue();
+    }
+
+    @Override
+    public void setValue(long value) {
+      realCounter.setValue(value);
+    }
+
+    @Override
+    public void increment(long incr) {
+      realCounter.increment(incr);
+    }
+
+    @Override
+    public void write(DataOutput out) throws IOException {
+      realCounter.write(out);
+    }
+
+    @Override
+    public void readFields(DataInput in) throws IOException {
+      realCounter.readFields(in);
+    }
 
     /**
      * Returns the compact stringified version of the counter in the format
      * [(actual-name)(display-name)(value)]
      * @return the stringified result
      */
-    String makeEscapedCompactString();
+    public String makeEscapedCompactString() {
+      return toEscapedCompactString(realCounter);
+    }
 
     /**
      * Checks for (content) equality of two (basic) counters
@@ -88,39 +164,42 @@ public class Counters
      * @deprecated
      */
     @Deprecated
-    boolean contentEquals(Counter counter);
+    public boolean contentEquals(Counter counter) {
+      return realCounter.equals(counter.getUnderlyingCounter());
+    }
 
     /**
      * @return the value of the counter
      */
-    long getCounter();
-  }
-
-  static class OldCounterImpl extends GenericCounter implements Counter {
-
-    OldCounterImpl() {
-    }
-
-    OldCounterImpl(String name, String displayName, long value) {
-      super(name, displayName, value);
-    }
-
-    @Override
-    public synchronized String makeEscapedCompactString() {
-      return toEscapedCompactString(this);
-    }
-
-    @Override @Deprecated
-    public boolean contentEquals(Counter counter) {
-      return equals(counter);
-    }
-
-    @Override
     public long getCounter() {
-      return getValue();
+      return realCounter.getValue();
+    }
+
+    @Override
+    public org.apache.hadoop.mapreduce.Counter getUnderlyingCounter() {
+      return realCounter;
+    }
+    
+    @Override
+    public synchronized boolean equals(Object genericRight) {
+      if (genericRight instanceof Counter) {
+        synchronized (genericRight) {
+          Counter right = (Counter) genericRight;
+          return getName().equals(right.getName()) &&
+                 getDisplayName().equals(right.getDisplayName()) &&
+                 getValue() == right.getValue();
+        }
+      }
+      return false;
+    }
+    
+    @Override
+    public int hashCode() {
+      return realCounter.hashCode();
     }
   }
 
+
   /**
    *  <code>Group</code> of counters, comprising of counters from a particular
    *  counter {@link Enum} class.
@@ -128,21 +207,38 @@ public class Counters
    *  <p><code>Group</code>handles localization of the class name and the
    *  counter names.</p>
    */
-  public static interface Group extends CounterGroupBase<Counter> {
-
+  public static class Group implements CounterGroupBase<Counter> {
+    private CounterGroupBase<Counter> realGroup;
+    
+    Group(GenericGroup group) {
+      this.realGroup = group;
+    }
+    Group(FSGroupImpl group) {
+      this.realGroup = group;
+    }
+    
+    @SuppressWarnings({ "unchecked", "rawtypes" })
+    Group(FrameworkGroupImpl group) {
+      this.realGroup = group;
+    }
+    
     /**
      * @param counterName the name of the counter
      * @return the value of the specified counter, or 0 if the counter does
      * not exist.
      */
-    long getCounter(String counterName);
+    public long getCounter(String counterName)  {
+      return getCounterValue(realGroup, counterName);
+    }
 
     /**
      * @return the compact stringified version of the group in the format
      * {(actual-name)(display-name)(value)[][][]} where [] are compact strings
      * for the counters within.
      */
-    String makeEscapedCompactString();
+    public String makeEscapedCompactString() {
+      return toEscapedCompactString(realGroup);
+    }
 
     /**
      * Get the counter for the given id and create it if it doesn't exist.
@@ -152,172 +248,184 @@ public class Counters
      * @deprecated use {@link #findCounter(String)} instead
      */
     @Deprecated
-    Counter getCounter(int id, String name);
+    public Counter getCounter(int id, String name) {
+      return findCounter(name);
+    }
 
     /**
      * Get the counter for the given name and create it if it doesn't exist.
      * @param name the internal counter name
      * @return the counter
      */
-    Counter getCounterForName(String name);
+    public Counter getCounterForName(String name) {
+      return findCounter(name);
+    }
+
+    @Override
+    public void write(DataOutput out) throws IOException {
+     realGroup.write(out); 
+    }
+
+    @Override
+    public void readFields(DataInput in) throws IOException {
+      realGroup.readFields(in);
+    }
+
+    @Override
+    public Iterator<Counter> iterator() {
+      return realGroup.iterator();
+    }
+
+    @Override
+    public String getName() {
+      return realGroup.getName();
+    }
+
+    @Override
+    public String getDisplayName() {
+      return realGroup.getDisplayName();
+    }
+
+    @Override
+    public void setDisplayName(String displayName) {
+      realGroup.setDisplayName(displayName);
+    }
+
+    @Override
+    public void addCounter(Counter counter) {
+      realGroup.addCounter(counter);
+    }
+
+    @Override
+    public Counter addCounter(String name, String displayName, long value) {
+      return realGroup.addCounter(name, displayName, value);
+    }
+
+    @Override
+    public Counter findCounter(String counterName, String displayName) {
+      return realGroup.findCounter(counterName, displayName);
+    }
+
+    @Override
+    public Counter findCounter(String counterName, boolean create) {
+      return realGroup.findCounter(counterName, create);
+    }
+
+    @Override
+    public Counter findCounter(String counterName) {
+      return realGroup.findCounter(counterName);
+    }
+
+    @Override
+    public int size() {
+      return realGroup.size();
+    }
+
+    @Override
+    public void incrAllCounters(CounterGroupBase<Counter> rightGroup) {
+      realGroup.incrAllCounters(rightGroup);
+    }
+    
+    @Override
+    public CounterGroupBase<Counter> getUnderlyingGroup() {
+      return realGroup;
+    }
+
+    @Override
+    public synchronized boolean equals(Object genericRight) {
+      if (genericRight instanceof CounterGroupBase<?>) {
+        @SuppressWarnings("unchecked")
+        CounterGroupBase<Counter> right = ((CounterGroupBase<Counter>) 
+        genericRight).getUnderlyingGroup();
+        return Iterators.elementsEqual(iterator(), right.iterator());
+      }
+      return false;
+    }
+
+    @Override
+    public int hashCode() {
+      return realGroup.hashCode();
+    }
   }
 
   // All the group impls need this for legacy group interface
-  static long getCounterValue(Group group, String counterName) {
+  static long getCounterValue(CounterGroupBase<Counter> group, String counterName) {
     Counter counter = group.findCounter(counterName, false);
     if (counter != null) return counter.getValue();
     return 0L;
   }
 
   // Mix the generic group implementation into the Group interface
-  private static class GenericGroup extends AbstractCounterGroup<Counter>
-                                    implements Group {
+  private static class GenericGroup extends AbstractCounterGroup<Counter> {
 
     GenericGroup(String name, String displayName, Limits limits) {
       super(name, displayName, limits);
     }
 
-    @Override
-    public long getCounter(String counterName) {
-      return getCounterValue(this, counterName);
-    }
-
-    @Override
-    public String makeEscapedCompactString() {
-      return toEscapedCompactString(this);
-    }
-
-    @Override
-    public Counter getCounter(int id, String name) {
-      return findCounter(name);
-    }
-
-    @Override
-    public Counter getCounterForName(String name) {
-      return findCounter(name);
-    }
-
     @Override
     protected Counter newCounter(String counterName, String displayName,
                                  long value) {
-      return new OldCounterImpl(counterName, displayName, value);
+      return new Counter(new GenericCounter(counterName, displayName, value));
     }
 
     @Override
     protected Counter newCounter() {
-      return new OldCounterImpl();
+      return new Counter();
+    }
+    
+    @Override
+    public CounterGroupBase<Counter> getUnderlyingGroup() {
+     return this;
     }
   }
 
   // Mix the framework group implementation into the Group interface
   private static class FrameworkGroupImpl<T extends Enum<T>>
-      extends FrameworkCounterGroup<T, Counter> implements Group {
-
-    // Mix the framework counter implmementation into the Counter interface
-    class FrameworkCounterImpl extends FrameworkCounter implements Counter {
+      extends FrameworkCounterGroup<T, Counter> {
 
+    // Mix the framework counter implementation into the Counter interface
+    class FrameworkCounterImpl extends FrameworkCounter {
       FrameworkCounterImpl(T key) {
         super(key);
       }
 
-      @Override
-      public String makeEscapedCompactString() {
-        return toEscapedCompactString(this);
-      }
-
-      @Override
-      public boolean contentEquals(Counter counter) {
-        return equals(counter);
-      }
-
-      @Override
-      public long getCounter() {
-        return getValue();
-      }
     }
 
     FrameworkGroupImpl(Class<T> cls) {
       super(cls);
     }
 
-    @Override
-    public long getCounter(String counterName) {
-      return getCounterValue(this, counterName);
-    }
-
-    @Override
-    public String makeEscapedCompactString() {
-      return toEscapedCompactString(this);
-    }
-
-    @Override @Deprecated
-    public Counter getCounter(int id, String name) {
-      return findCounter(name);
-    }
-
-    @Override
-    public Counter getCounterForName(String name) {
-      return findCounter(name);
-    }
-
     @Override
     protected Counter newCounter(T key) {
-      return new FrameworkCounterImpl(key);
+      return new Counter(new FrameworkCounterImpl(key));
+    }
+
+    @Override
+    public CounterGroupBase<Counter> getUnderlyingGroup() {
+      return this;
     }
   }
 
   // Mix the file system counter group implementation into the Group interface
-  private static class FSGroupImpl extends FileSystemCounterGroup<Counter>
-                                   implements Group {
+  private static class FSGroupImpl extends FileSystemCounterGroup<Counter> {
 
-    private class FSCounterImpl extends FSCounter implements Counter {
+    private class FSCounterImpl extends FSCounter {
 
       FSCounterImpl(String scheme, FileSystemCounter key) {
         super(scheme, key);
       }
 
-      @Override
-      public String makeEscapedCompactString() {
-        return toEscapedCompactString(this);
-      }
-
-      @Override @Deprecated
-      public boolean contentEquals(Counter counter) {
-        throw new UnsupportedOperationException("Not supported yet.");
-      }
-
-      @Override
-      public long getCounter() {
-        return getValue();
-      }
-
     }
 
     @Override
     protected Counter newCounter(String scheme, FileSystemCounter key) {
-      return new FSCounterImpl(scheme, key);
+      return new Counter(new FSCounterImpl(scheme, key));
     }
 
     @Override
-    public long getCounter(String counterName) {
-      return getCounterValue(this, counterName);
+    public CounterGroupBase<Counter> getUnderlyingGroup() {
+      return this;
     }
-
-    @Override
-    public String makeEscapedCompactString() {
-      return toEscapedCompactString(this);
-    }
-
-    @Override @Deprecated
-    public Counter getCounter(int id, String name) {
-      return findCounter(name);
-    }
-
-    @Override
-    public Counter getCounterForName(String name) {
-      return findCounter(name);
-    }
-
   }
 
   public synchronized Counter findCounter(String group, String name) {
@@ -342,7 +450,7 @@ public class Counters
     FrameworkGroupFactory<Group> newFrameworkGroupFactory(final Class<T> cls) {
       return new FrameworkGroupFactory<Group>() {
         @Override public Group newGroup(String name) {
-          return new FrameworkGroupImpl<T>(cls); // impl in this package
+          return new Group(new FrameworkGroupImpl<T>(cls)); // impl in this package
         }
       };
     }
@@ -350,12 +458,12 @@ public class Counters
     @Override
     protected Group newGenericGroup(String name, String displayName,
                                     Limits limits) {
-      return new GenericGroup(name, displayName, limits);
+      return new Group(new GenericGroup(name, displayName, limits));
     }
 
     @Override
     protected Group newFileSystemGroup() {
-      return new FSGroupImpl();
+      return new Group(new FSGroupImpl());
     }
   }
 

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/Counter.java

@@ -72,4 +72,10 @@ public interface Counter extends Writable {
    * @param incr the value to increase this counter by
    */
   void increment(long incr);
+ 
+  /**
+   * Return the underlying object if this is a facade.
+   * @return the undelying object.
+   */
+  Counter getUnderlyingCounter();
 }

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/Counters.java

@@ -52,6 +52,11 @@ public class Counters extends AbstractCounters<Counter, CounterGroup> {
     protected FrameworkCounter newCounter(T key) {
       return new FrameworkCounter(key);
     }
+
+    @Override
+    public CounterGroupBase<Counter> getUnderlyingGroup() {
+      return this;
+    }
   }
 
   // Mix generic group implementation into CounterGroup interface
@@ -72,6 +77,11 @@ public class Counters extends AbstractCounters<Counter, CounterGroup> {
     protected Counter newCounter() {
       return new GenericCounter();
     }
+
+    @Override
+    public CounterGroupBase<Counter> getUnderlyingGroup() {
+      return this;
+    }
   }
 
   // Mix file system group implementation into the CounterGroup interface
@@ -82,6 +92,11 @@ public class Counters extends AbstractCounters<Counter, CounterGroup> {
     protected Counter newCounter(String scheme, FileSystemCounter key) {
       return new FSCounter(scheme, key);
     }
+
+    @Override
+    public CounterGroupBase<Counter> getUnderlyingGroup() {
+      return this;
+    }
   }
 
   /**

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/counters/AbstractCounters.java

@@ -172,7 +172,8 @@ public abstract class AbstractCounters<C extends Counter,
   @InterfaceAudience.Private
   public synchronized C findCounter(String scheme, FileSystemCounter key) {
     return ((FileSystemCounterGroup<C>) getGroup(
-        FileSystemCounter.class.getName())).findCounter(scheme, key);
+        FileSystemCounter.class.getName()).getUnderlyingGroup()).
+        findCounter(scheme, key);
   }
 
   /**
@@ -243,11 +244,11 @@ public abstract class AbstractCounters<C extends Counter,
     WritableUtils.writeVInt(out, groupFactory.version());
     WritableUtils.writeVInt(out, fgroups.size());  // framework groups first
     for (G group : fgroups.values()) {
-      if (group instanceof FrameworkCounterGroup<?, ?>) {
+      if (group.getUnderlyingGroup() instanceof FrameworkCounterGroup<?, ?>) {
         WritableUtils.writeVInt(out, GroupType.FRAMEWORK.ordinal());
         WritableUtils.writeVInt(out, getFrameworkGroupId(group.getName()));
         group.write(out);
-      } else if (group instanceof FileSystemCounterGroup<?>) {
+      } else if (group.getUnderlyingGroup() instanceof FileSystemCounterGroup<?>) {
         WritableUtils.writeVInt(out, GroupType.FILESYSTEM.ordinal());
         group.write(out);
       }

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/counters/CounterGroupBase.java

@@ -98,4 +98,10 @@ public interface CounterGroupBase<T extends Counter>
    * @param rightGroup  the group to be added to this group
    */
   void incrAllCounters(CounterGroupBase<T> rightGroup);
+  
+  /**
+   * Exposes the underlying group type if a facade.
+   * @return the underlying object that this object is wrapping up.
+   */
+  CounterGroupBase<T> getUnderlyingGroup();
 }

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/counters/FileSystemCounterGroup.java

@@ -110,6 +110,11 @@ public abstract class FileSystemCounterGroup<C extends Counter>
     public void readFields(DataInput in) throws IOException {
       assert false : "shouldn't be called";
     }
+
+    @Override
+    public Counter getUnderlyingCounter() {
+      return this;
+    }
   }
 
   @Override
@@ -231,10 +236,10 @@ public abstract class FileSystemCounterGroup<C extends Counter>
   @Override
   @SuppressWarnings("unchecked")
   public void incrAllCounters(CounterGroupBase<C> other) {
-    if (checkNotNull(other, "other group")
+    if (checkNotNull(other.getUnderlyingGroup(), "other group")
         instanceof FileSystemCounterGroup<?>) {
       for (Counter counter : other) {
-        FSCounter c = (FSCounter) counter;
+        FSCounter c = (FSCounter) ((Counter)counter).getUnderlyingCounter();
         findCounter(c.scheme, c.key) .increment(counter.getValue());
       }
     }
@@ -253,7 +258,7 @@ public abstract class FileSystemCounterGroup<C extends Counter>
       for (Object counter : entry.getValue()) {
         if (counter == null) continue;
         @SuppressWarnings("unchecked")
-        FSCounter c = (FSCounter) counter;
+        FSCounter c = (FSCounter) ((Counter)counter).getUnderlyingCounter();
         WritableUtils.writeVInt(out, c.key.ordinal());  // key
         WritableUtils.writeVLong(out, c.getValue());    // value
       }

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/counters/FrameworkCounterGroup.java

@@ -18,21 +18,24 @@
 
 package org.apache.hadoop.mapreduce.counters;
 
+import static com.google.common.base.Preconditions.checkNotNull;
+
 import java.io.DataInput;
 import java.io.DataOutput;
 import java.io.IOException;
 import java.util.Arrays;
 import java.util.Iterator;
 
-import static com.google.common.base.Preconditions.*;
-import com.google.common.collect.AbstractIterator;
-import com.google.common.collect.Iterators;
-
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.io.WritableUtils;
 import org.apache.hadoop.mapreduce.Counter;
 import org.apache.hadoop.mapreduce.util.ResourceBundles;
 
+import com.google.common.collect.AbstractIterator;
+import com.google.common.collect.Iterators;
+
 /**
  * An abstract class to provide common implementation for the framework
  * counter group in both mapred and mapreduce packages.
@@ -43,7 +46,8 @@ import org.apache.hadoop.mapreduce.util.ResourceBundles;
 @InterfaceAudience.Private
 public abstract class FrameworkCounterGroup<T extends Enum<T>,
     C extends Counter> implements CounterGroupBase<C> {
-
+  private static final Log LOG = LogFactory.getLog(FrameworkCounterGroup.class);
+  
   private final Class<T> enumClass; // for Enum.valueOf
   private final Object[] counters;  // local casts are OK and save a class ref
   private String displayName = null;
@@ -95,6 +99,11 @@ public abstract class FrameworkCounterGroup<T extends Enum<T>,
     public void readFields(DataInput in) throws IOException {
       assert false : "shouldn't be called";
     }
+
+    @Override
+    public Counter getUnderlyingCounter() {
+      return this;
+    }
   }
 
   @SuppressWarnings("unchecked")

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapreduce/counters/GenericCounter.java

@@ -25,6 +25,7 @@ import java.io.IOException;
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.io.Text;
 import org.apache.hadoop.io.WritableUtils;
+import org.apache.hadoop.mapreduce.Counter;
 
 /**
  * A generic counter implementation
@@ -101,4 +102,9 @@ public class GenericCounter extends AbstractCounter {
   public synchronized void increment(long incr) {
     value += incr;
   }
+
+  @Override
+  public Counter getUnderlyingCounter() {
+    return this;
+  }
 }

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/test/java/org/apache/hadoop/mapred/TestCounters.java

@@ -24,6 +24,8 @@ import java.text.ParseException;
 import java.util.Iterator;
 import java.util.Random;
 
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.mapred.Counters.Counter;
 import org.apache.hadoop.mapred.Counters.Group;
 import org.apache.hadoop.mapreduce.FileSystemCounter;
@@ -37,6 +39,7 @@ import org.junit.Test;
 public class TestCounters {
   enum myCounters {TEST1, TEST2};
   private static final long MAX_VALUE = 10;
+  private static final Log LOG = LogFactory.getLog(TestCounters.class);
   
   // Generates enum based counters
   private Counters getEnumCounters(Enum[] keys) {

hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/test/java/org/apache/hadoop/mapred/TestJobCounters.java

@@ -18,6 +18,10 @@
 
 package org.apache.hadoop.mapred;
 
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
+
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Formatter;
@@ -25,11 +29,6 @@ import java.util.Iterator;
 import java.util.List;
 import java.util.StringTokenizer;
 
-import org.junit.AfterClass;
-import org.junit.BeforeClass;
-import org.junit.Test;
-import static org.junit.Assert.*;
-
 import org.apache.commons.lang.RandomStringUtils;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.FSDataOutputStream;
@@ -40,12 +39,14 @@ import org.apache.hadoop.io.LongWritable;
 import org.apache.hadoop.io.Text;
 import org.apache.hadoop.io.Writable;
 import org.apache.hadoop.io.WritableComparable;
-import org.apache.hadoop.mapreduce.Cluster;
 import org.apache.hadoop.mapreduce.Job;
 import org.apache.hadoop.mapreduce.TaskCounter;
 import org.apache.hadoop.mapreduce.TaskType;
 import org.apache.hadoop.mapreduce.lib.input.FileInputFormatCounter;
 import org.apache.hadoop.mapreduce.lib.output.FileOutputFormatCounter;
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+import org.junit.Test;
 
 /**
  * This is an wordcount application that tests the count of records