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Posted to common-commits@hadoop.apache.org by sz...@apache.org on 2012/10/19 04:27:38 UTC

svn commit: r1399950 [10/17] - in /hadoop/common/branches/HDFS-2802/hadoop-common-project: hadoop-annotations/ hadoop-annotations/src/main/java/org/apache/hadoop/classification/tools/ hadoop-auth-examples/ hadoop-auth/ hadoop-auth/src/main/java/org/apa...

Modified: hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/spi/AbstractMetricsContext.java
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/spi/AbstractMetricsContext.java?rev=1399950&r1=1399949&r2=1399950&view=diff
==============================================================================
--- hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/spi/AbstractMetricsContext.java (original)
+++ hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/spi/AbstractMetricsContext.java Fri Oct 19 02:25:55 2012
@@ -1,481 +1,491 @@
-/*
- * AbstractMetricsContext.java
- *
- * 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.metrics.spi;
-
-import java.io.IOException;
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.HashMap;
-import java.util.HashSet;
-import java.util.Iterator;
-import java.util.List;
-import java.util.Map;
-import java.util.Set;
-import java.util.Timer;
-import java.util.TimerTask;
-import java.util.TreeMap;
-import java.util.Map.Entry;
-
-import org.apache.hadoop.classification.InterfaceAudience;
-import org.apache.hadoop.classification.InterfaceStability;
-import org.apache.hadoop.metrics.ContextFactory;
-import org.apache.hadoop.metrics.MetricsContext;
-import org.apache.hadoop.metrics.MetricsException;
-import org.apache.hadoop.metrics.MetricsRecord;
-import org.apache.hadoop.metrics.Updater;
-
-/**
- * The main class of the Service Provider Interface.  This class should be
- * extended in order to integrate the Metrics API with a specific metrics
- * client library. <p/>
- *
- * This class implements the internal table of metric data, and the timer
- * on which data is to be sent to the metrics system.  Subclasses must
- * override the abstract <code>emitRecord</code> method in order to transmit
- * the data. <p/>
- */
-@InterfaceAudience.Public
-@InterfaceStability.Evolving
-public abstract class AbstractMetricsContext implements MetricsContext {
-    
-  private int period = MetricsContext.DEFAULT_PERIOD;
-  private Timer timer = null;
-    
-  private Set<Updater> updaters = new HashSet<Updater>(1);
-  private volatile boolean isMonitoring = false;
-    
-  private ContextFactory factory = null;
-  private String contextName = null;
-    
-  @InterfaceAudience.Private
-  public static class TagMap extends TreeMap<String,Object> {
-    private static final long serialVersionUID = 3546309335061952993L;
-    TagMap() {
-      super();
-    }
-    TagMap(TagMap orig) {
-      super(orig);
-    }
-    /**
-     * Returns true if this tagmap contains every tag in other.
-     */
-    public boolean containsAll(TagMap other) {
-      for (Map.Entry<String,Object> entry : other.entrySet()) {
-        Object value = get(entry.getKey());
-        if (value == null || !value.equals(entry.getValue())) {
-          // either key does not exist here, or the value is different
-          return false;
-        }
-      }
-      return true;
-    }
-  }
-  
-  @InterfaceAudience.Private
-  public static class MetricMap extends TreeMap<String,Number> {
-    private static final long serialVersionUID = -7495051861141631609L;
-    MetricMap() {
-      super();
-    }
-    MetricMap(MetricMap orig) {
-      super(orig);
-    }
-  }
-            
-  static class RecordMap extends HashMap<TagMap,MetricMap> {
-    private static final long serialVersionUID = 259835619700264611L;
-  }
-    
-  private Map<String,RecordMap> bufferedData = new HashMap<String,RecordMap>();
-    
-
-  /**
-   * Creates a new instance of AbstractMetricsContext
-   */
-  protected AbstractMetricsContext() {
-  }
-    
-  /**
-   * Initializes the context.
-   */
-  public void init(String contextName, ContextFactory factory) 
-  {
-    this.contextName = contextName;
-    this.factory = factory;
-  }
-    
-  /**
-   * Convenience method for subclasses to access factory attributes.
-   */
-  protected String getAttribute(String attributeName) {
-    String factoryAttribute = contextName + "." + attributeName;
-    return (String) factory.getAttribute(factoryAttribute);  
-  }
-    
-  /**
-   * Returns an attribute-value map derived from the factory attributes
-   * by finding all factory attributes that begin with 
-   * <i>contextName</i>.<i>tableName</i>.  The returned map consists of
-   * those attributes with the contextName and tableName stripped off.
-   */
-  protected Map<String,String> getAttributeTable(String tableName) {
-    String prefix = contextName + "." + tableName + ".";
-    Map<String,String> result = new HashMap<String,String>();
-    for (String attributeName : factory.getAttributeNames()) {
-      if (attributeName.startsWith(prefix)) {
-        String name = attributeName.substring(prefix.length());
-        String value = (String) factory.getAttribute(attributeName);
-        result.put(name, value);
-      }
-    }
-    return result;
-  }
-    
-  /**
-   * Returns the context name.
-   */
-  public String getContextName() {
-    return contextName;
-  }
-    
-  /**
-   * Returns the factory by which this context was created.
-   */
-  public ContextFactory getContextFactory() {
-    return factory;
-  }
-    
-  /**
-   * Starts or restarts monitoring, the emitting of metrics records.
-   */
-  public synchronized void startMonitoring()
-    throws IOException {
-    if (!isMonitoring) {
-      startTimer();
-      isMonitoring = true;
-    }
-  }
-    
-  /**
-   * Stops monitoring.  This does not free buffered data. 
-   * @see #close()
-   */
-  public synchronized void stopMonitoring() {
-    if (isMonitoring) {
-      stopTimer();
-      isMonitoring = false;
-    }
-  }
-    
-  /**
-   * Returns true if monitoring is currently in progress.
-   */
-  public boolean isMonitoring() {
-    return isMonitoring;
-  }
-    
-  /**
-   * Stops monitoring and frees buffered data, returning this
-   * object to its initial state.  
-   */
-  public synchronized void close() {
-    stopMonitoring();
-    clearUpdaters();
-  } 
-    
-  /**
-   * Creates a new AbstractMetricsRecord instance with the given <code>recordName</code>.
-   * Throws an exception if the metrics implementation is configured with a fixed
-   * set of record names and <code>recordName</code> is not in that set.
-   * 
-   * @param recordName the name of the record
-   * @throws MetricsException if recordName conflicts with configuration data
-   */
-  public final synchronized MetricsRecord createRecord(String recordName) {
-    if (bufferedData.get(recordName) == null) {
-      bufferedData.put(recordName, new RecordMap());
-    }
-    return newRecord(recordName);
-  }
-    
-  /**
-   * Subclasses should override this if they subclass MetricsRecordImpl.
-   * @param recordName the name of the record
-   * @return newly created instance of MetricsRecordImpl or subclass
-   */
-  protected MetricsRecord newRecord(String recordName) {
-    return new MetricsRecordImpl(recordName, this);
-  }
-    
-  /**
-   * Registers a callback to be called at time intervals determined by
-   * the configuration.
-   *
-   * @param updater object to be run periodically; it should update
-   * some metrics records 
-   */
-  public synchronized void registerUpdater(final Updater updater) {
-    if (!updaters.contains(updater)) {
-      updaters.add(updater);
-    }
-  }
-    
-  /**
-   * Removes a callback, if it exists.
-   *
-   * @param updater object to be removed from the callback list
-   */
-  public synchronized void unregisterUpdater(Updater updater) {
-    updaters.remove(updater);
-  }
-    
-  private synchronized void clearUpdaters() {
-    updaters.clear();
-  }
-    
-  /**
-   * Starts timer if it is not already started
-   */
-  private synchronized void startTimer() {
-    if (timer == null) {
-      timer = new Timer("Timer thread for monitoring " + getContextName(), 
-                        true);
-      TimerTask task = new TimerTask() {
-          public void run() {
-            try {
-              timerEvent();
-            }
-            catch (IOException ioe) {
-              ioe.printStackTrace();
-            }
-          }
-        };
-      long millis = period * 1000;
-      timer.scheduleAtFixedRate(task, millis, millis);
-    }
-  }
-    
-  /**
-   * Stops timer if it is running
-   */
-  private synchronized void stopTimer() {
-    if (timer != null) {
-      timer.cancel();
-      timer = null;
-    }
-  }
-    
-  /**
-   * Timer callback.
-   */
-  private void timerEvent() throws IOException {
-    if (isMonitoring) {
-      Collection<Updater> myUpdaters;
-      synchronized (this) {
-        myUpdaters = new ArrayList<Updater>(updaters);
-      }     
-      // Run all the registered updates without holding a lock
-      // on this context
-      for (Updater updater : myUpdaters) {
-        try {
-          updater.doUpdates(this);
-        }
-        catch (Throwable throwable) {
-          throwable.printStackTrace();
-        }
-      }
-      emitRecords();
-    }
-  }
-    
-  /**
-   *  Emits the records.
-   */
-  private synchronized void emitRecords() throws IOException {
-    for (String recordName : bufferedData.keySet()) {
-      RecordMap recordMap = bufferedData.get(recordName);
-      synchronized (recordMap) {
-        Set<Entry<TagMap, MetricMap>> entrySet = recordMap.entrySet ();
-        for (Entry<TagMap, MetricMap> entry : entrySet) {
-          OutputRecord outRec = new OutputRecord(entry.getKey(), entry.getValue());
-          emitRecord(contextName, recordName, outRec);
-        }
-      }
-    }
-    flush();
-  }
-  
-  /**
-   * Retrieves all the records managed by this MetricsContext.
-   * Useful for monitoring systems that are polling-based.
-   * @return A non-null collection of all monitoring records.
-   */
-  public synchronized Map<String, Collection<OutputRecord>> getAllRecords() {
-    Map<String, Collection<OutputRecord>> out = new TreeMap<String, Collection<OutputRecord>>();
-    for (String recordName : bufferedData.keySet()) {
-      RecordMap recordMap = bufferedData.get(recordName);
-      synchronized (recordMap) {
-        List<OutputRecord> records = new ArrayList<OutputRecord>();
-        Set<Entry<TagMap, MetricMap>> entrySet = recordMap.entrySet();
-        for (Entry<TagMap, MetricMap> entry : entrySet) {
-          OutputRecord outRec = new OutputRecord(entry.getKey(), entry.getValue());
-          records.add(outRec);
-        }
-        out.put(recordName, records);
-      }
-    }
-    return out;
-  }
-
-  /**
-   * Sends a record to the metrics system.
-   */
-  protected abstract void emitRecord(String contextName, String recordName, 
-                                     OutputRecord outRec) throws IOException;
-    
-  /**
-   * Called each period after all records have been emitted, this method does nothing.
-   * Subclasses may override it in order to perform some kind of flush.
-   */
-  protected void flush() throws IOException {
-  }
-    
-  /**
-   * Called by MetricsRecordImpl.update().  Creates or updates a row in
-   * the internal table of metric data.
-   */
-  protected void update(MetricsRecordImpl record) {
-    String recordName = record.getRecordName();
-    TagMap tagTable = record.getTagTable();
-    Map<String,MetricValue> metricUpdates = record.getMetricTable();
-        
-    RecordMap recordMap = getRecordMap(recordName);
-    synchronized (recordMap) {
-      MetricMap metricMap = recordMap.get(tagTable);
-      if (metricMap == null) {
-        metricMap = new MetricMap();
-        TagMap tagMap = new TagMap(tagTable); // clone tags
-        recordMap.put(tagMap, metricMap);
-      }
-
-      Set<Entry<String, MetricValue>> entrySet = metricUpdates.entrySet();
-      for (Entry<String, MetricValue> entry : entrySet) {
-        String metricName = entry.getKey ();
-        MetricValue updateValue = entry.getValue ();
-        Number updateNumber = updateValue.getNumber();
-        Number currentNumber = metricMap.get(metricName);
-        if (currentNumber == null || updateValue.isAbsolute()) {
-          metricMap.put(metricName, updateNumber);
-        }
-        else {
-          Number newNumber = sum(updateNumber, currentNumber);
-          metricMap.put(metricName, newNumber);
-        }
-      }
-    }
-  }
-    
-  private synchronized RecordMap getRecordMap(String recordName) {
-    return bufferedData.get(recordName);
-  }
-    
-  /**
-   * Adds two numbers, coercing the second to the type of the first.
-   *
-   */
-  private Number sum(Number a, Number b) {
-    if (a instanceof Integer) {
-      return Integer.valueOf(a.intValue() + b.intValue());
-    }
-    else if (a instanceof Float) {
-      return new Float(a.floatValue() + b.floatValue());
-    }
-    else if (a instanceof Short) {
-      return Short.valueOf((short)(a.shortValue() + b.shortValue()));
-    }
-    else if (a instanceof Byte) {
-      return Byte.valueOf((byte)(a.byteValue() + b.byteValue()));
-    }
-    else if (a instanceof Long) {
-      return Long.valueOf((a.longValue() + b.longValue()));
-    }
-    else {
-      // should never happen
-      throw new MetricsException("Invalid number type");
-    }
-            
-  }
-    
-  /**
-   * Called by MetricsRecordImpl.remove().  Removes all matching rows in
-   * the internal table of metric data.  A row matches if it has the same
-   * tag names and values as record, but it may also have additional
-   * tags.
-   */    
-  protected void remove(MetricsRecordImpl record) {
-    String recordName = record.getRecordName();
-    TagMap tagTable = record.getTagTable();
-        
-    RecordMap recordMap = getRecordMap(recordName);
-    synchronized (recordMap) {
-      Iterator<TagMap> it = recordMap.keySet().iterator();
-      while (it.hasNext()) {
-        TagMap rowTags = it.next();
-        if (rowTags.containsAll(tagTable)) {
-          it.remove();
-        }
-      }
-    }
-  }
-    
-  /**
-   * Returns the timer period.
-   */
-  public int getPeriod() {
-    return period;
-  }
-    
-  /**
-   * Sets the timer period
-   */
-  protected void setPeriod(int period) {
-    this.period = period;
-  }
-  
-  /**
-   * If a period is set in the attribute passed in, override
-   * the default with it.
-   */
-  protected void parseAndSetPeriod(String attributeName) {
-    String periodStr = getAttribute(attributeName);
-    if (periodStr != null) {
-      int period = 0;
-      try {
-        period = Integer.parseInt(periodStr);
-      } catch (NumberFormatException nfe) {
-      }
-      if (period <= 0) {
-        throw new MetricsException("Invalid period: " + periodStr);
-      }
-      setPeriod(period);
-    }
-  }
-}
+/*
+ * AbstractMetricsContext.java
+ *
+ * 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.metrics.spi;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.Timer;
+import java.util.TimerTask;
+import java.util.TreeMap;
+import java.util.Map.Entry;
+
+import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.classification.InterfaceStability;
+import org.apache.hadoop.metrics.ContextFactory;
+import org.apache.hadoop.metrics.MetricsContext;
+import org.apache.hadoop.metrics.MetricsException;
+import org.apache.hadoop.metrics.MetricsRecord;
+import org.apache.hadoop.metrics.Updater;
+
+/**
+ * The main class of the Service Provider Interface.  This class should be
+ * extended in order to integrate the Metrics API with a specific metrics
+ * client library. <p/>
+ *
+ * This class implements the internal table of metric data, and the timer
+ * on which data is to be sent to the metrics system.  Subclasses must
+ * override the abstract <code>emitRecord</code> method in order to transmit
+ * the data. <p/>
+ */
+@InterfaceAudience.Public
+@InterfaceStability.Evolving
+public abstract class AbstractMetricsContext implements MetricsContext {
+    
+  private int period = MetricsContext.DEFAULT_PERIOD;
+  private Timer timer = null;
+    
+  private Set<Updater> updaters = new HashSet<Updater>(1);
+  private volatile boolean isMonitoring = false;
+    
+  private ContextFactory factory = null;
+  private String contextName = null;
+    
+  @InterfaceAudience.Private
+  public static class TagMap extends TreeMap<String,Object> {
+    private static final long serialVersionUID = 3546309335061952993L;
+    TagMap() {
+      super();
+    }
+    TagMap(TagMap orig) {
+      super(orig);
+    }
+    /**
+     * Returns true if this tagmap contains every tag in other.
+     */
+    public boolean containsAll(TagMap other) {
+      for (Map.Entry<String,Object> entry : other.entrySet()) {
+        Object value = get(entry.getKey());
+        if (value == null || !value.equals(entry.getValue())) {
+          // either key does not exist here, or the value is different
+          return false;
+        }
+      }
+      return true;
+    }
+  }
+  
+  @InterfaceAudience.Private
+  public static class MetricMap extends TreeMap<String,Number> {
+    private static final long serialVersionUID = -7495051861141631609L;
+    MetricMap() {
+      super();
+    }
+    MetricMap(MetricMap orig) {
+      super(orig);
+    }
+  }
+            
+  static class RecordMap extends HashMap<TagMap,MetricMap> {
+    private static final long serialVersionUID = 259835619700264611L;
+  }
+    
+  private Map<String,RecordMap> bufferedData = new HashMap<String,RecordMap>();
+    
+
+  /**
+   * Creates a new instance of AbstractMetricsContext
+   */
+  protected AbstractMetricsContext() {
+  }
+    
+  /**
+   * Initializes the context.
+   */
+  @Override
+  public void init(String contextName, ContextFactory factory) 
+  {
+    this.contextName = contextName;
+    this.factory = factory;
+  }
+    
+  /**
+   * Convenience method for subclasses to access factory attributes.
+   */
+  protected String getAttribute(String attributeName) {
+    String factoryAttribute = contextName + "." + attributeName;
+    return (String) factory.getAttribute(factoryAttribute);  
+  }
+    
+  /**
+   * Returns an attribute-value map derived from the factory attributes
+   * by finding all factory attributes that begin with 
+   * <i>contextName</i>.<i>tableName</i>.  The returned map consists of
+   * those attributes with the contextName and tableName stripped off.
+   */
+  protected Map<String,String> getAttributeTable(String tableName) {
+    String prefix = contextName + "." + tableName + ".";
+    Map<String,String> result = new HashMap<String,String>();
+    for (String attributeName : factory.getAttributeNames()) {
+      if (attributeName.startsWith(prefix)) {
+        String name = attributeName.substring(prefix.length());
+        String value = (String) factory.getAttribute(attributeName);
+        result.put(name, value);
+      }
+    }
+    return result;
+  }
+    
+  /**
+   * Returns the context name.
+   */
+  @Override
+  public String getContextName() {
+    return contextName;
+  }
+    
+  /**
+   * Returns the factory by which this context was created.
+   */
+  public ContextFactory getContextFactory() {
+    return factory;
+  }
+    
+  /**
+   * Starts or restarts monitoring, the emitting of metrics records.
+   */
+  @Override
+  public synchronized void startMonitoring()
+    throws IOException {
+    if (!isMonitoring) {
+      startTimer();
+      isMonitoring = true;
+    }
+  }
+    
+  /**
+   * Stops monitoring.  This does not free buffered data. 
+   * @see #close()
+   */
+  @Override
+  public synchronized void stopMonitoring() {
+    if (isMonitoring) {
+      stopTimer();
+      isMonitoring = false;
+    }
+  }
+    
+  /**
+   * Returns true if monitoring is currently in progress.
+   */
+  @Override
+  public boolean isMonitoring() {
+    return isMonitoring;
+  }
+    
+  /**
+   * Stops monitoring and frees buffered data, returning this
+   * object to its initial state.  
+   */
+  @Override
+  public synchronized void close() {
+    stopMonitoring();
+    clearUpdaters();
+  } 
+    
+  /**
+   * Creates a new AbstractMetricsRecord instance with the given <code>recordName</code>.
+   * Throws an exception if the metrics implementation is configured with a fixed
+   * set of record names and <code>recordName</code> is not in that set.
+   * 
+   * @param recordName the name of the record
+   * @throws MetricsException if recordName conflicts with configuration data
+   */
+  @Override
+  public final synchronized MetricsRecord createRecord(String recordName) {
+    if (bufferedData.get(recordName) == null) {
+      bufferedData.put(recordName, new RecordMap());
+    }
+    return newRecord(recordName);
+  }
+    
+  /**
+   * Subclasses should override this if they subclass MetricsRecordImpl.
+   * @param recordName the name of the record
+   * @return newly created instance of MetricsRecordImpl or subclass
+   */
+  protected MetricsRecord newRecord(String recordName) {
+    return new MetricsRecordImpl(recordName, this);
+  }
+    
+  /**
+   * Registers a callback to be called at time intervals determined by
+   * the configuration.
+   *
+   * @param updater object to be run periodically; it should update
+   * some metrics records 
+   */
+  @Override
+  public synchronized void registerUpdater(final Updater updater) {
+    if (!updaters.contains(updater)) {
+      updaters.add(updater);
+    }
+  }
+    
+  /**
+   * Removes a callback, if it exists.
+   *
+   * @param updater object to be removed from the callback list
+   */
+  @Override
+  public synchronized void unregisterUpdater(Updater updater) {
+    updaters.remove(updater);
+  }
+    
+  private synchronized void clearUpdaters() {
+    updaters.clear();
+  }
+    
+  /**
+   * Starts timer if it is not already started
+   */
+  private synchronized void startTimer() {
+    if (timer == null) {
+      timer = new Timer("Timer thread for monitoring " + getContextName(), 
+                        true);
+      TimerTask task = new TimerTask() {
+          @Override
+          public void run() {
+            try {
+              timerEvent();
+            } catch (IOException ioe) {
+              ioe.printStackTrace();
+            }
+          }
+        };
+      long millis = period * 1000;
+      timer.scheduleAtFixedRate(task, millis, millis);
+    }
+  }
+    
+  /**
+   * Stops timer if it is running
+   */
+  private synchronized void stopTimer() {
+    if (timer != null) {
+      timer.cancel();
+      timer = null;
+    }
+  }
+    
+  /**
+   * Timer callback.
+   */
+  private void timerEvent() throws IOException {
+    if (isMonitoring) {
+      Collection<Updater> myUpdaters;
+      synchronized (this) {
+        myUpdaters = new ArrayList<Updater>(updaters);
+      }     
+      // Run all the registered updates without holding a lock
+      // on this context
+      for (Updater updater : myUpdaters) {
+        try {
+          updater.doUpdates(this);
+        } catch (Throwable throwable) {
+          throwable.printStackTrace();
+        }
+      }
+      emitRecords();
+    }
+  }
+    
+  /**
+   *  Emits the records.
+   */
+  private synchronized void emitRecords() throws IOException {
+    for (String recordName : bufferedData.keySet()) {
+      RecordMap recordMap = bufferedData.get(recordName);
+      synchronized (recordMap) {
+        Set<Entry<TagMap, MetricMap>> entrySet = recordMap.entrySet ();
+        for (Entry<TagMap, MetricMap> entry : entrySet) {
+          OutputRecord outRec = new OutputRecord(entry.getKey(), entry.getValue());
+          emitRecord(contextName, recordName, outRec);
+        }
+      }
+    }
+    flush();
+  }
+  
+  /**
+   * Retrieves all the records managed by this MetricsContext.
+   * Useful for monitoring systems that are polling-based.
+   * @return A non-null collection of all monitoring records.
+   */
+  @Override
+  public synchronized Map<String, Collection<OutputRecord>> getAllRecords() {
+    Map<String, Collection<OutputRecord>> out = new TreeMap<String, Collection<OutputRecord>>();
+    for (String recordName : bufferedData.keySet()) {
+      RecordMap recordMap = bufferedData.get(recordName);
+      synchronized (recordMap) {
+        List<OutputRecord> records = new ArrayList<OutputRecord>();
+        Set<Entry<TagMap, MetricMap>> entrySet = recordMap.entrySet();
+        for (Entry<TagMap, MetricMap> entry : entrySet) {
+          OutputRecord outRec = new OutputRecord(entry.getKey(), entry.getValue());
+          records.add(outRec);
+        }
+        out.put(recordName, records);
+      }
+    }
+    return out;
+  }
+
+  /**
+   * Sends a record to the metrics system.
+   */
+  protected abstract void emitRecord(String contextName, String recordName, 
+                                     OutputRecord outRec) throws IOException;
+    
+  /**
+   * Called each period after all records have been emitted, this method does nothing.
+   * Subclasses may override it in order to perform some kind of flush.
+   */
+  protected void flush() throws IOException {
+  }
+    
+  /**
+   * Called by MetricsRecordImpl.update().  Creates or updates a row in
+   * the internal table of metric data.
+   */
+  protected void update(MetricsRecordImpl record) {
+    String recordName = record.getRecordName();
+    TagMap tagTable = record.getTagTable();
+    Map<String,MetricValue> metricUpdates = record.getMetricTable();
+        
+    RecordMap recordMap = getRecordMap(recordName);
+    synchronized (recordMap) {
+      MetricMap metricMap = recordMap.get(tagTable);
+      if (metricMap == null) {
+        metricMap = new MetricMap();
+        TagMap tagMap = new TagMap(tagTable); // clone tags
+        recordMap.put(tagMap, metricMap);
+      }
+
+      Set<Entry<String, MetricValue>> entrySet = metricUpdates.entrySet();
+      for (Entry<String, MetricValue> entry : entrySet) {
+        String metricName = entry.getKey ();
+        MetricValue updateValue = entry.getValue ();
+        Number updateNumber = updateValue.getNumber();
+        Number currentNumber = metricMap.get(metricName);
+        if (currentNumber == null || updateValue.isAbsolute()) {
+          metricMap.put(metricName, updateNumber);
+        }
+        else {
+          Number newNumber = sum(updateNumber, currentNumber);
+          metricMap.put(metricName, newNumber);
+        }
+      }
+    }
+  }
+    
+  private synchronized RecordMap getRecordMap(String recordName) {
+    return bufferedData.get(recordName);
+  }
+    
+  /**
+   * Adds two numbers, coercing the second to the type of the first.
+   *
+   */
+  private Number sum(Number a, Number b) {
+    if (a instanceof Integer) {
+      return Integer.valueOf(a.intValue() + b.intValue());
+    }
+    else if (a instanceof Float) {
+      return new Float(a.floatValue() + b.floatValue());
+    }
+    else if (a instanceof Short) {
+      return Short.valueOf((short)(a.shortValue() + b.shortValue()));
+    }
+    else if (a instanceof Byte) {
+      return Byte.valueOf((byte)(a.byteValue() + b.byteValue()));
+    }
+    else if (a instanceof Long) {
+      return Long.valueOf((a.longValue() + b.longValue()));
+    }
+    else {
+      // should never happen
+      throw new MetricsException("Invalid number type");
+    }
+            
+  }
+    
+  /**
+   * Called by MetricsRecordImpl.remove().  Removes all matching rows in
+   * the internal table of metric data.  A row matches if it has the same
+   * tag names and values as record, but it may also have additional
+   * tags.
+   */    
+  protected void remove(MetricsRecordImpl record) {
+    String recordName = record.getRecordName();
+    TagMap tagTable = record.getTagTable();
+        
+    RecordMap recordMap = getRecordMap(recordName);
+    synchronized (recordMap) {
+      Iterator<TagMap> it = recordMap.keySet().iterator();
+      while (it.hasNext()) {
+        TagMap rowTags = it.next();
+        if (rowTags.containsAll(tagTable)) {
+          it.remove();
+        }
+      }
+    }
+  }
+    
+  /**
+   * Returns the timer period.
+   */
+  @Override
+  public int getPeriod() {
+    return period;
+  }
+    
+  /**
+   * Sets the timer period
+   */
+  protected void setPeriod(int period) {
+    this.period = period;
+  }
+  
+  /**
+   * If a period is set in the attribute passed in, override
+   * the default with it.
+   */
+  protected void parseAndSetPeriod(String attributeName) {
+    String periodStr = getAttribute(attributeName);
+    if (periodStr != null) {
+      int period = 0;
+      try {
+        period = Integer.parseInt(periodStr);
+      } catch (NumberFormatException nfe) {
+      }
+      if (period <= 0) {
+        throw new MetricsException("Invalid period: " + periodStr);
+      }
+      setPeriod(period);
+    }
+  }
+}

Modified: hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/spi/CompositeContext.java
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/spi/CompositeContext.java?rev=1399950&r1=1399949&r2=1399950&view=diff
==============================================================================
--- hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/spi/CompositeContext.java (original)
+++ hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/spi/CompositeContext.java Fri Oct 19 02:25:55 2012
@@ -30,7 +30,6 @@ import org.apache.hadoop.classification.
 import org.apache.hadoop.classification.InterfaceStability;
 import org.apache.hadoop.metrics.ContextFactory;
 import org.apache.hadoop.metrics.MetricsContext;
-import org.apache.hadoop.metrics.MetricsException;
 import org.apache.hadoop.metrics.MetricsRecord;
 import org.apache.hadoop.metrics.MetricsUtil;
 import org.apache.hadoop.metrics.Updater;
@@ -49,6 +48,7 @@ public class CompositeContext extends Ab
   public CompositeContext() {
   }
 
+  @Override
   @InterfaceAudience.Private
   public void init(String contextName, ContextFactory factory) {
     super.init(contextName, factory);
@@ -186,6 +186,7 @@ public class CompositeContext extends Ab
       }
     }
 
+    @Override
     public Object invoke(Object p, Method m, Object[] args) throws Throwable {
       if (m_getRecordName.equals(m)) {
         return recordName;

Modified: hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/spi/MetricsRecordImpl.java
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/spi/MetricsRecordImpl.java?rev=1399950&r1=1399949&r2=1399950&view=diff
==============================================================================
--- hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/spi/MetricsRecordImpl.java (original)
+++ hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/spi/MetricsRecordImpl.java Fri Oct 19 02:25:55 2012
@@ -1,281 +1,300 @@
-/*
- * MetricsRecordImpl.java
- *
- * 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.metrics.spi;
-
-import java.util.LinkedHashMap;
-import java.util.Map;
-
-import org.apache.hadoop.classification.InterfaceAudience;
-import org.apache.hadoop.classification.InterfaceStability;
-import org.apache.hadoop.metrics.MetricsException;
-import org.apache.hadoop.metrics.MetricsRecord;
-import org.apache.hadoop.metrics.spi.AbstractMetricsContext.TagMap;
-
-/**
- * An implementation of MetricsRecord.  Keeps a back-pointer to the context
- * from which it was created, and delegates back to it on <code>update</code>
- * and <code>remove()</code>.
- */
-@InterfaceAudience.Public
-@InterfaceStability.Evolving
-public class MetricsRecordImpl implements MetricsRecord {
-    
-  private TagMap tagTable = new TagMap();
-  private Map<String,MetricValue> metricTable = new LinkedHashMap<String,MetricValue>();
-    
-  private String recordName;
-  private AbstractMetricsContext context;
-    
-    
-  /** Creates a new instance of FileRecord */
-  protected MetricsRecordImpl(String recordName, AbstractMetricsContext context)
-  {
-    this.recordName = recordName;
-    this.context = context;
-  }
-    
-  /**
-   * Returns the record name. 
-   *
-   * @return the record name
-   */
-  public String getRecordName() {
-    return recordName;
-  }
-    
-  /**
-   * Sets the named tag to the specified value.
-   *
-   * @param tagName name of the tag
-   * @param tagValue new value of the tag
-   * @throws MetricsException if the tagName conflicts with the configuration
-   */
-  public void setTag(String tagName, String tagValue) {
-    if (tagValue == null) {
-      tagValue = "";
-    }
-    tagTable.put(tagName, tagValue);
-  }
-    
-  /**
-   * Sets the named tag to the specified value.
-   *
-   * @param tagName name of the tag
-   * @param tagValue new value of the tag
-   * @throws MetricsException if the tagName conflicts with the configuration
-   */
-  public void setTag(String tagName, int tagValue) {
-    tagTable.put(tagName, Integer.valueOf(tagValue));
-  }
-    
-  /**
-   * Sets the named tag to the specified value.
-   *
-   * @param tagName name of the tag
-   * @param tagValue new value of the tag
-   * @throws MetricsException if the tagName conflicts with the configuration
-   */
-  public void setTag(String tagName, long tagValue) {
-    tagTable.put(tagName, Long.valueOf(tagValue));
-  }
-    
-  /**
-   * Sets the named tag to the specified value.
-   *
-   * @param tagName name of the tag
-   * @param tagValue new value of the tag
-   * @throws MetricsException if the tagName conflicts with the configuration
-   */
-  public void setTag(String tagName, short tagValue) {
-    tagTable.put(tagName, Short.valueOf(tagValue));
-  }
-    
-  /**
-   * Sets the named tag to the specified value.
-   *
-   * @param tagName name of the tag
-   * @param tagValue new value of the tag
-   * @throws MetricsException if the tagName conflicts with the configuration
-   */
-  public void setTag(String tagName, byte tagValue) {
-    tagTable.put(tagName, Byte.valueOf(tagValue));
-  }
-    
-  /**
-   * Removes any tag of the specified name.
-   */
-  public void removeTag(String tagName) {
-    tagTable.remove(tagName);
-  }
-  
-  /**
-   * Sets the named metric to the specified value.
-   *
-   * @param metricName name of the metric
-   * @param metricValue new value of the metric
-   * @throws MetricsException if the metricName or the type of the metricValue 
-   * conflicts with the configuration
-   */
-  public void setMetric(String metricName, int metricValue) {
-    setAbsolute(metricName, Integer.valueOf(metricValue));
-  }
-    
-  /**
-   * Sets the named metric to the specified value.
-   *
-   * @param metricName name of the metric
-   * @param metricValue new value of the metric
-   * @throws MetricsException if the metricName or the type of the metricValue 
-   * conflicts with the configuration
-   */
-  public void setMetric(String metricName, long metricValue) {
-    setAbsolute(metricName, Long.valueOf(metricValue));
-  }
-    
-  /**
-   * Sets the named metric to the specified value.
-   *
-   * @param metricName name of the metric
-   * @param metricValue new value of the metric
-   * @throws MetricsException if the metricName or the type of the metricValue 
-   * conflicts with the configuration
-   */
-  public void setMetric(String metricName, short metricValue) {
-    setAbsolute(metricName, Short.valueOf(metricValue));
-  }
-    
-  /**
-   * Sets the named metric to the specified value.
-   *
-   * @param metricName name of the metric
-   * @param metricValue new value of the metric
-   * @throws MetricsException if the metricName or the type of the metricValue 
-   * conflicts with the configuration
-   */
-  public void setMetric(String metricName, byte metricValue) {
-    setAbsolute(metricName, Byte.valueOf(metricValue));
-  }
-    
-  /**
-   * Sets the named metric to the specified value.
-   *
-   * @param metricName name of the metric
-   * @param metricValue new value of the metric
-   * @throws MetricsException if the metricName or the type of the metricValue 
-   * conflicts with the configuration
-   */
-  public void setMetric(String metricName, float metricValue) {
-    setAbsolute(metricName, new Float(metricValue));
-  }
-    
-  /**
-   * Increments the named metric by the specified value.
-   *
-   * @param metricName name of the metric
-   * @param metricValue incremental value
-   * @throws MetricsException if the metricName or the type of the metricValue 
-   * conflicts with the configuration
-   */
-  public void incrMetric(String metricName, int metricValue) {
-    setIncrement(metricName, Integer.valueOf(metricValue));
-  }
-    
-  /**
-   * Increments the named metric by the specified value.
-   *
-   * @param metricName name of the metric
-   * @param metricValue incremental value
-   * @throws MetricsException if the metricName or the type of the metricValue 
-   * conflicts with the configuration
-   */
-  public void incrMetric(String metricName, long metricValue) {
-    setIncrement(metricName, Long.valueOf(metricValue));
-  }
-    
-  /**
-   * Increments the named metric by the specified value.
-   *
-   * @param metricName name of the metric
-   * @param metricValue incremental value
-   * @throws MetricsException if the metricName or the type of the metricValue 
-   * conflicts with the configuration
-   */
-  public void incrMetric(String metricName, short metricValue) {
-    setIncrement(metricName, Short.valueOf(metricValue));
-  }
-    
-  /**
-   * Increments the named metric by the specified value.
-   *
-   * @param metricName name of the metric
-   * @param metricValue incremental value
-   * @throws MetricsException if the metricName or the type of the metricValue 
-   * conflicts with the configuration
-   */
-  public void incrMetric(String metricName, byte metricValue) {
-    setIncrement(metricName, Byte.valueOf(metricValue));
-  }
-    
-  /**
-   * Increments the named metric by the specified value.
-   *
-   * @param metricName name of the metric
-   * @param metricValue incremental value
-   * @throws MetricsException if the metricName or the type of the metricValue 
-   * conflicts with the configuration
-   */
-  public void incrMetric(String metricName, float metricValue) {
-    setIncrement(metricName, new Float(metricValue));
-  }
-    
-  private void setAbsolute(String metricName, Number metricValue) {
-    metricTable.put(metricName, new MetricValue(metricValue, MetricValue.ABSOLUTE));
-  }
-    
-  private void setIncrement(String metricName, Number metricValue) {
-    metricTable.put(metricName, new MetricValue(metricValue, MetricValue.INCREMENT));
-  }
-    
-  /**
-   * Updates the table of buffered data which is to be sent periodically.
-   * If the tag values match an existing row, that row is updated; 
-   * otherwise, a new row is added.
-   */
-  public void update() {
-    context.update(this);
-  }
-    
-  /**
-   * Removes the row, if it exists, in the buffered data table having tags 
-   * that equal the tags that have been set on this record. 
-   */
-  public void remove() {
-    context.remove(this);
-  }
-
-  TagMap getTagTable() {
-    return tagTable;
-  }
-
-  Map<String, MetricValue> getMetricTable() {
-    return metricTable;
-  }
-}
+/*
+ * MetricsRecordImpl.java
+ *
+ * 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.metrics.spi;
+
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.classification.InterfaceStability;
+import org.apache.hadoop.metrics.MetricsException;
+import org.apache.hadoop.metrics.MetricsRecord;
+import org.apache.hadoop.metrics.spi.AbstractMetricsContext.TagMap;
+
+/**
+ * An implementation of MetricsRecord.  Keeps a back-pointer to the context
+ * from which it was created, and delegates back to it on <code>update</code>
+ * and <code>remove()</code>.
+ */
+@InterfaceAudience.Public
+@InterfaceStability.Evolving
+public class MetricsRecordImpl implements MetricsRecord {
+    
+  private TagMap tagTable = new TagMap();
+  private Map<String,MetricValue> metricTable = new LinkedHashMap<String,MetricValue>();
+    
+  private String recordName;
+  private AbstractMetricsContext context;
+    
+    
+  /** Creates a new instance of FileRecord */
+  protected MetricsRecordImpl(String recordName, AbstractMetricsContext context)
+  {
+    this.recordName = recordName;
+    this.context = context;
+  }
+    
+  /**
+   * Returns the record name. 
+   *
+   * @return the record name
+   */
+  @Override
+  public String getRecordName() {
+    return recordName;
+  }
+    
+  /**
+   * Sets the named tag to the specified value.
+   *
+   * @param tagName name of the tag
+   * @param tagValue new value of the tag
+   * @throws MetricsException if the tagName conflicts with the configuration
+   */
+  @Override
+  public void setTag(String tagName, String tagValue) {
+    if (tagValue == null) {
+      tagValue = "";
+    }
+    tagTable.put(tagName, tagValue);
+  }
+    
+  /**
+   * Sets the named tag to the specified value.
+   *
+   * @param tagName name of the tag
+   * @param tagValue new value of the tag
+   * @throws MetricsException if the tagName conflicts with the configuration
+   */
+  @Override
+  public void setTag(String tagName, int tagValue) {
+    tagTable.put(tagName, Integer.valueOf(tagValue));
+  }
+    
+  /**
+   * Sets the named tag to the specified value.
+   *
+   * @param tagName name of the tag
+   * @param tagValue new value of the tag
+   * @throws MetricsException if the tagName conflicts with the configuration
+   */
+  @Override
+  public void setTag(String tagName, long tagValue) {
+    tagTable.put(tagName, Long.valueOf(tagValue));
+  }
+    
+  /**
+   * Sets the named tag to the specified value.
+   *
+   * @param tagName name of the tag
+   * @param tagValue new value of the tag
+   * @throws MetricsException if the tagName conflicts with the configuration
+   */
+  @Override
+  public void setTag(String tagName, short tagValue) {
+    tagTable.put(tagName, Short.valueOf(tagValue));
+  }
+    
+  /**
+   * Sets the named tag to the specified value.
+   *
+   * @param tagName name of the tag
+   * @param tagValue new value of the tag
+   * @throws MetricsException if the tagName conflicts with the configuration
+   */
+  @Override
+  public void setTag(String tagName, byte tagValue) {
+    tagTable.put(tagName, Byte.valueOf(tagValue));
+  }
+    
+  /**
+   * Removes any tag of the specified name.
+   */
+  @Override
+  public void removeTag(String tagName) {
+    tagTable.remove(tagName);
+  }
+  
+  /**
+   * Sets the named metric to the specified value.
+   *
+   * @param metricName name of the metric
+   * @param metricValue new value of the metric
+   * @throws MetricsException if the metricName or the type of the metricValue 
+   * conflicts with the configuration
+   */
+  @Override
+  public void setMetric(String metricName, int metricValue) {
+    setAbsolute(metricName, Integer.valueOf(metricValue));
+  }
+    
+  /**
+   * Sets the named metric to the specified value.
+   *
+   * @param metricName name of the metric
+   * @param metricValue new value of the metric
+   * @throws MetricsException if the metricName or the type of the metricValue 
+   * conflicts with the configuration
+   */
+  @Override
+  public void setMetric(String metricName, long metricValue) {
+    setAbsolute(metricName, Long.valueOf(metricValue));
+  }
+    
+  /**
+   * Sets the named metric to the specified value.
+   *
+   * @param metricName name of the metric
+   * @param metricValue new value of the metric
+   * @throws MetricsException if the metricName or the type of the metricValue 
+   * conflicts with the configuration
+   */
+  @Override
+  public void setMetric(String metricName, short metricValue) {
+    setAbsolute(metricName, Short.valueOf(metricValue));
+  }
+    
+  /**
+   * Sets the named metric to the specified value.
+   *
+   * @param metricName name of the metric
+   * @param metricValue new value of the metric
+   * @throws MetricsException if the metricName or the type of the metricValue 
+   * conflicts with the configuration
+   */
+  @Override
+  public void setMetric(String metricName, byte metricValue) {
+    setAbsolute(metricName, Byte.valueOf(metricValue));
+  }
+    
+  /**
+   * Sets the named metric to the specified value.
+   *
+   * @param metricName name of the metric
+   * @param metricValue new value of the metric
+   * @throws MetricsException if the metricName or the type of the metricValue 
+   * conflicts with the configuration
+   */
+  @Override
+  public void setMetric(String metricName, float metricValue) {
+    setAbsolute(metricName, new Float(metricValue));
+  }
+    
+  /**
+   * Increments the named metric by the specified value.
+   *
+   * @param metricName name of the metric
+   * @param metricValue incremental value
+   * @throws MetricsException if the metricName or the type of the metricValue 
+   * conflicts with the configuration
+   */
+  @Override
+  public void incrMetric(String metricName, int metricValue) {
+    setIncrement(metricName, Integer.valueOf(metricValue));
+  }
+    
+  /**
+   * Increments the named metric by the specified value.
+   *
+   * @param metricName name of the metric
+   * @param metricValue incremental value
+   * @throws MetricsException if the metricName or the type of the metricValue 
+   * conflicts with the configuration
+   */
+  @Override
+  public void incrMetric(String metricName, long metricValue) {
+    setIncrement(metricName, Long.valueOf(metricValue));
+  }
+    
+  /**
+   * Increments the named metric by the specified value.
+   *
+   * @param metricName name of the metric
+   * @param metricValue incremental value
+   * @throws MetricsException if the metricName or the type of the metricValue 
+   * conflicts with the configuration
+   */
+  @Override
+  public void incrMetric(String metricName, short metricValue) {
+    setIncrement(metricName, Short.valueOf(metricValue));
+  }
+    
+  /**
+   * Increments the named metric by the specified value.
+   *
+   * @param metricName name of the metric
+   * @param metricValue incremental value
+   * @throws MetricsException if the metricName or the type of the metricValue 
+   * conflicts with the configuration
+   */
+  @Override
+  public void incrMetric(String metricName, byte metricValue) {
+    setIncrement(metricName, Byte.valueOf(metricValue));
+  }
+    
+  /**
+   * Increments the named metric by the specified value.
+   *
+   * @param metricName name of the metric
+   * @param metricValue incremental value
+   * @throws MetricsException if the metricName or the type of the metricValue 
+   * conflicts with the configuration
+   */
+  @Override
+  public void incrMetric(String metricName, float metricValue) {
+    setIncrement(metricName, new Float(metricValue));
+  }
+    
+  private void setAbsolute(String metricName, Number metricValue) {
+    metricTable.put(metricName, new MetricValue(metricValue, MetricValue.ABSOLUTE));
+  }
+    
+  private void setIncrement(String metricName, Number metricValue) {
+    metricTable.put(metricName, new MetricValue(metricValue, MetricValue.INCREMENT));
+  }
+    
+  /**
+   * Updates the table of buffered data which is to be sent periodically.
+   * If the tag values match an existing row, that row is updated; 
+   * otherwise, a new row is added.
+   */
+  @Override
+  public void update() {
+    context.update(this);
+  }
+    
+  /**
+   * Removes the row, if it exists, in the buffered data table having tags 
+   * that equal the tags that have been set on this record. 
+   */
+  @Override
+  public void remove() {
+    context.remove(this);
+  }
+
+  TagMap getTagTable() {
+    return tagTable;
+  }
+
+  Map<String, MetricValue> getMetricTable() {
+    return metricTable;
+  }
+}

Modified: hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/spi/NoEmitMetricsContext.java
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/spi/NoEmitMetricsContext.java?rev=1399950&r1=1399949&r2=1399950&view=diff
==============================================================================
--- hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/spi/NoEmitMetricsContext.java (original)
+++ hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/spi/NoEmitMetricsContext.java Fri Oct 19 02:25:55 2012
@@ -40,6 +40,7 @@ public class NoEmitMetricsContext extend
     public NoEmitMetricsContext() {
     }
     
+    @Override
     @InterfaceAudience.Private
     public void init(String contextName, ContextFactory factory) {
       super.init(contextName, factory);
@@ -49,6 +50,7 @@ public class NoEmitMetricsContext extend
     /**
      * Do-nothing version of emitRecord
      */
+    @Override
     @InterfaceAudience.Private
     protected void emitRecord(String contextName, String recordName,
                               OutputRecord outRec) {

Modified: hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/spi/NullContext.java
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/spi/NullContext.java?rev=1399950&r1=1399949&r2=1399950&view=diff
==============================================================================
--- hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/spi/NullContext.java (original)
+++ hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/spi/NullContext.java Fri Oct 19 02:25:55 2012
@@ -40,6 +40,7 @@ public class NullContext extends Abstrac
   /**
    * Do-nothing version of startMonitoring
    */
+  @Override
   @InterfaceAudience.Private
   public void startMonitoring() {
   }
@@ -47,6 +48,7 @@ public class NullContext extends Abstrac
   /**
    * Do-nothing version of emitRecord
    */
+  @Override
   @InterfaceAudience.Private
   protected void emitRecord(String contextName, String recordName,
                             OutputRecord outRec) 
@@ -55,6 +57,7 @@ public class NullContext extends Abstrac
   /**
    * Do-nothing version of update
    */
+  @Override
   @InterfaceAudience.Private
   protected void update(MetricsRecordImpl record) {
   }
@@ -62,6 +65,7 @@ public class NullContext extends Abstrac
   /**
    * Do-nothing version of remove
    */
+  @Override
   @InterfaceAudience.Private
   protected void remove(MetricsRecordImpl record) {
   }

Modified: hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/spi/NullContextWithUpdateThread.java
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/spi/NullContextWithUpdateThread.java?rev=1399950&r1=1399949&r2=1399950&view=diff
==============================================================================
--- hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/spi/NullContextWithUpdateThread.java (original)
+++ hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/spi/NullContextWithUpdateThread.java Fri Oct 19 02:25:55 2012
@@ -21,7 +21,6 @@ package org.apache.hadoop.metrics.spi;
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.classification.InterfaceStability;
 import org.apache.hadoop.metrics.ContextFactory;
-import org.apache.hadoop.metrics.MetricsException;
 
 /**
  * A null context which has a thread calling 
@@ -46,6 +45,7 @@ public class NullContextWithUpdateThread
   public NullContextWithUpdateThread() {
   }
   
+  @Override
   @InterfaceAudience.Private
   public void init(String contextName, ContextFactory factory) {
     super.init(contextName, factory);
@@ -56,6 +56,7 @@ public class NullContextWithUpdateThread
   /**
    * Do-nothing version of emitRecord
    */
+  @Override
   @InterfaceAudience.Private
   protected void emitRecord(String contextName, String recordName,
                             OutputRecord outRec) 
@@ -64,6 +65,7 @@ public class NullContextWithUpdateThread
   /**
    * Do-nothing version of update
    */
+  @Override
   @InterfaceAudience.Private
   protected void update(MetricsRecordImpl record) {
   }
@@ -71,6 +73,7 @@ public class NullContextWithUpdateThread
   /**
    * Do-nothing version of remove
    */
+  @Override
   @InterfaceAudience.Private
   protected void remove(MetricsRecordImpl record) {
   }

Modified: hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/spi/OutputRecord.java
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/spi/OutputRecord.java?rev=1399950&r1=1399949&r2=1399950&view=diff
==============================================================================
--- hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/spi/OutputRecord.java (original)
+++ hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/spi/OutputRecord.java Fri Oct 19 02:25:55 2012
@@ -21,11 +21,7 @@
 package org.apache.hadoop.metrics.spi;
 
 import java.util.Collections;
-import java.util.Map;
 import java.util.Set;
-import java.util.TreeMap;
-import java.util.Map.Entry;
-
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.classification.InterfaceStability;
 import org.apache.hadoop.metrics.spi.AbstractMetricsContext.MetricMap;

Modified: hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/spi/Util.java
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/spi/Util.java?rev=1399950&r1=1399949&r2=1399950&view=diff
==============================================================================
--- hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/spi/Util.java (original)
+++ hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/spi/Util.java Fri Oct 19 02:25:55 2012
@@ -22,7 +22,6 @@
 package org.apache.hadoop.metrics.spi;
 
 import java.net.InetSocketAddress;
-import java.net.SocketAddress;
 import java.util.ArrayList;
 import java.util.List;
 

Modified: hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/util/MetricsDynamicMBeanBase.java
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/util/MetricsDynamicMBeanBase.java?rev=1399950&r1=1399949&r2=1399950&view=diff
==============================================================================
--- hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/util/MetricsDynamicMBeanBase.java (original)
+++ hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/util/MetricsDynamicMBeanBase.java Fri Oct 19 02:25:55 2012
@@ -129,7 +129,7 @@ public abstract class MetricsDynamicMBea
   @Override
   public Object getAttribute(String attributeName) throws AttributeNotFoundException,
       MBeanException, ReflectionException {
-    if (attributeName == null || attributeName.equals("")) 
+    if (attributeName == null || attributeName.isEmpty()) 
       throw new IllegalArgumentException();
     
     updateMbeanInfoIfMetricsListChanged();
@@ -197,7 +197,7 @@ public abstract class MetricsDynamicMBea
   public Object invoke(String actionName, Object[] parms, String[] signature)
       throws MBeanException, ReflectionException {
     
-    if (actionName == null || actionName.equals("")) 
+    if (actionName == null || actionName.isEmpty()) 
       throw new IllegalArgumentException();
     
     

Modified: hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/util/MetricsIntValue.java
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/util/MetricsIntValue.java?rev=1399950&r1=1399949&r2=1399950&view=diff
==============================================================================
--- hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/util/MetricsIntValue.java (original)
+++ hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/util/MetricsIntValue.java Fri Oct 19 02:25:55 2012
@@ -19,8 +19,6 @@ package org.apache.hadoop.metrics.util;
 
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.metrics.MetricsRecord;
-import org.apache.hadoop.util.StringUtils;
-
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
@@ -92,6 +90,7 @@ public class MetricsIntValue extends Met
    *
    * @param mr
    */
+  @Override
   public synchronized void pushMetric(final MetricsRecord mr) {
     if (changed) {
       try {

Modified: hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/util/MetricsLongValue.java
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/util/MetricsLongValue.java?rev=1399950&r1=1399949&r2=1399950&view=diff
==============================================================================
--- hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/util/MetricsLongValue.java (original)
+++ hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/util/MetricsLongValue.java Fri Oct 19 02:25:55 2012
@@ -82,6 +82,7 @@ public class MetricsLongValue extends Me
    *
    * @param mr
    */
+  @Override
   public synchronized void pushMetric(final MetricsRecord mr) {
     if (changed) 
       mr.setMetric(getName(), value);

Modified: hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/util/MetricsTimeVaryingInt.java
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/util/MetricsTimeVaryingInt.java?rev=1399950&r1=1399949&r2=1399950&view=diff
==============================================================================
--- hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/util/MetricsTimeVaryingInt.java (original)
+++ hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/util/MetricsTimeVaryingInt.java Fri Oct 19 02:25:55 2012
@@ -19,8 +19,6 @@ package org.apache.hadoop.metrics.util;
 
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.metrics.MetricsRecord;
-import org.apache.hadoop.util.StringUtils;
-
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
@@ -101,6 +99,7 @@ public class MetricsTimeVaryingInt exten
    *
    * @param mr
    */
+  @Override
   public synchronized void pushMetric(final MetricsRecord mr) {
     intervalHeartBeat();
     try {

Modified: hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/util/MetricsTimeVaryingLong.java
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/util/MetricsTimeVaryingLong.java?rev=1399950&r1=1399949&r2=1399950&view=diff
==============================================================================
--- hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/util/MetricsTimeVaryingLong.java (original)
+++ hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/util/MetricsTimeVaryingLong.java Fri Oct 19 02:25:55 2012
@@ -20,8 +20,6 @@ package org.apache.hadoop.metrics.util;
 
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.metrics.MetricsRecord;
-import org.apache.hadoop.util.StringUtils;
-
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
@@ -97,6 +95,7 @@ public class MetricsTimeVaryingLong exte
    *
    * @param mr
    */
+  @Override
   public synchronized void pushMetric(final MetricsRecord mr) {
     intervalHeartBeat();
     try {

Modified: hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/util/MetricsTimeVaryingRate.java
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/util/MetricsTimeVaryingRate.java?rev=1399950&r1=1399949&r2=1399950&view=diff
==============================================================================
--- hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/util/MetricsTimeVaryingRate.java (original)
+++ hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics/util/MetricsTimeVaryingRate.java Fri Oct 19 02:25:55 2012
@@ -19,8 +19,6 @@ package org.apache.hadoop.metrics.util;
 
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.metrics.MetricsRecord;
-import org.apache.hadoop.util.StringUtils;
-
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
@@ -144,6 +142,7 @@ public class MetricsTimeVaryingRate exte
    *
    * @param mr
    */
+  @Override
   public synchronized void pushMetric(final MetricsRecord mr) {
     intervalHeartBeat();
     try {

Modified: hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/MetricsCollector.java
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/MetricsCollector.java?rev=1399950&r1=1399949&r2=1399950&view=diff
==============================================================================
--- hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/MetricsCollector.java (original)
+++ hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/MetricsCollector.java Fri Oct 19 02:25:55 2012
@@ -30,14 +30,14 @@ public interface MetricsCollector {
   /**
    * Add a metrics record
    * @param name  of the record
-   * @return  a metrics record builder for the record
+   * @return  a {@link MetricsRecordBuilder} for the record {@code name}
    */
   public MetricsRecordBuilder addRecord(String name);
 
   /**
    * Add a metrics record
    * @param info  of the record
-   * @return  a metrics record builder for the record
+   * @return  a {@link MetricsRecordBuilder} for metrics {@code info}
    */
   public MetricsRecordBuilder addRecord(MetricsInfo info);
 }

Modified: hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/MetricsFilter.java
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/MetricsFilter.java?rev=1399950&r1=1399949&r2=1399950&view=diff
==============================================================================
--- hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/MetricsFilter.java (original)
+++ hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/MetricsFilter.java Fri Oct 19 02:25:55 2012
@@ -22,7 +22,9 @@ import org.apache.hadoop.classification.
 import org.apache.hadoop.classification.InterfaceStability;
 
 /**
- * The metrics filter interface
+ * The metrics filter interface. The MetricsFilter objects can be used either to
+ * filter the metrics from {@link MetricsSource}s or to filter metrics per
+ * {@link MetricsSink}.
  */
 @InterfaceAudience.Public
 @InterfaceStability.Evolving

Modified: hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/MetricsInfo.java
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/MetricsInfo.java?rev=1399950&r1=1399949&r2=1399950&view=diff
==============================================================================
--- hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/MetricsInfo.java (original)
+++ hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/MetricsInfo.java Fri Oct 19 02:25:55 2012
@@ -20,19 +20,24 @@ package org.apache.hadoop.metrics2;
 
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.classification.InterfaceStability;
+import org.apache.hadoop.metrics2.annotation.Metric;
 
 /**
- * Interface to provide immutable meta info for metrics
+ * Interface to provide immutable metainfo for metrics.
  */
 @InterfaceAudience.Public
 @InterfaceStability.Evolving
 public interface MetricsInfo {
   /**
+   * Typically name corresponds to annotation {@link Metric#value()} or
+   * the name of the class.
    * @return the name of the metric/tag
    */
   String name();
 
   /**
+   * Typically the description corresponds to annotation {@link Metric#about()}
+   * or the name of the class.
    * @return the description of the metric/tag
    */
   String description();

Modified: hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/MetricsRecord.java
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/MetricsRecord.java?rev=1399950&r1=1399949&r2=1399950&view=diff
==============================================================================
--- hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/MetricsRecord.java (original)
+++ hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/MetricsRecord.java Fri Oct 19 02:25:55 2012
@@ -36,17 +36,17 @@ public interface MetricsRecord {
   long timestamp();
 
   /**
-   * @return the record name
+   * @return the metrics record name
    */
   String name();
 
   /**
-   * @return the description of the record
+   * @return the description of the metrics record
    */
   String description();
 
   /**
-   * @return the context name of the record
+   * @return the context name of the metrics record
    */
   String context();
 

Modified: hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/MetricsRecordBuilder.java
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/MetricsRecordBuilder.java?rev=1399950&r1=1399949&r2=1399950&view=diff
==============================================================================
--- hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/MetricsRecordBuilder.java (original)
+++ hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/MetricsRecordBuilder.java Fri Oct 19 02:25:55 2012
@@ -28,7 +28,7 @@ import org.apache.hadoop.classification.
 @InterfaceStability.Evolving
 public abstract class MetricsRecordBuilder {
   /**
-   * Add a metrics tag
+   * Add a metrics value with metrics information
    * @param info  metadata of the tag
    * @param value of the tag
    * @return self

Modified: hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/MetricsSink.java
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/MetricsSink.java?rev=1399950&r1=1399949&r2=1399950&view=diff
==============================================================================
--- hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/MetricsSink.java (original)
+++ hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/MetricsSink.java Fri Oct 19 02:25:55 2012
@@ -22,7 +22,11 @@ import org.apache.hadoop.classification.
 import org.apache.hadoop.classification.InterfaceStability;
 
 /**
- * The metrics sink interface
+ * The metrics sink interface. <p>
+ * Implementations of this interface consume the {@link MetricsRecord} generated
+ * from {@link MetricsSource}. It registers with {@link MetricsSystem} which
+ * periodically pushes the {@link MetricsRecord} to the sink using
+ * {@link #putMetrics(MetricsRecord)} method.
  */
 @InterfaceAudience.Public
 @InterfaceStability.Evolving

Modified: hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/MetricsSource.java
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/MetricsSource.java?rev=1399950&r1=1399949&r2=1399950&view=diff
==============================================================================
--- hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/MetricsSource.java (original)
+++ hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/MetricsSource.java Fri Oct 19 02:25:55 2012
@@ -22,13 +22,15 @@ import org.apache.hadoop.classification.
 import org.apache.hadoop.classification.InterfaceStability;
 
 /**
- * The metrics source interface
+ * The source of metrics information. It generates and updates metrics. It
+ * registers with {@link MetricsSystem}, which periodically polls it to collect
+ * {@link MetricsRecord} and passes it to {@link MetricsSink}.
  */
 @InterfaceAudience.Public
 @InterfaceStability.Evolving
 public interface MetricsSource {
   /**
-   * Get metrics from the source
+   * Get metrics from the metrics source
    * @param collector to contain the resulting metrics snapshot
    * @param all if true, return all metrics even if unchanged.
    */

Modified: hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/MetricsSystem.java
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/MetricsSystem.java?rev=1399950&r1=1399949&r2=1399950&view=diff
==============================================================================
--- hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/MetricsSystem.java (original)
+++ hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/MetricsSystem.java Fri Oct 19 02:25:55 2012
@@ -22,7 +22,18 @@ import org.apache.hadoop.classification.
 import org.apache.hadoop.classification.InterfaceStability;
 
 /**
- * The metrics system interface
+ * The metrics system interface.
+ * 
+ * The following components are used for metrics.
+ * <ul>
+ * <li>{@link MetricsSource} generate and update metrics information.</li>
+ * <li>{@link MetricsSink} consume the metrics information</li>
+ * </ul>
+ * 
+ * {@link MetricsSource} and {@link MetricsSink} register with the metrics
+ * system. Implementations of {@link MetricsSystem} polls the
+ * {@link MetricsSource}s periodically and pass the {@link MetricsRecord}s to
+ * {@link MetricsSink}.
  */
 @InterfaceAudience.Public
 @InterfaceStability.Evolving

Modified: hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/annotation/Metric.java
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/annotation/Metric.java?rev=1399950&r1=1399949&r2=1399950&view=diff
==============================================================================
--- hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/annotation/Metric.java (original)
+++ hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/annotation/Metric.java Fri Oct 19 02:25:55 2012
@@ -24,7 +24,8 @@ import org.apache.hadoop.classification.
 import org.apache.hadoop.classification.InterfaceStability;
 
 /**
- * Annotation interface for a single metric
+ * Annotation interface for a single metric used to annotate a field or a method
+ * in the class.
  */
 @InterfaceAudience.Public
 @InterfaceStability.Evolving

Modified: hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/impl/MetricsConfig.java
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/impl/MetricsConfig.java?rev=1399950&r1=1399949&r2=1399950&view=diff
==============================================================================
--- hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/impl/MetricsConfig.java (original)
+++ hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/impl/MetricsConfig.java Fri Oct 19 02:25:55 2012
@@ -24,7 +24,6 @@ import java.net.URL;
 import java.net.URLClassLoader;
 import static java.security.AccessController.*;
 import java.security.PrivilegedAction;
-import java.util.Arrays;
 import java.util.Iterator;
 import java.util.Locale;
 import java.util.Map;
@@ -114,8 +113,7 @@ class MetricsConfig extends SubsetConfig
         MetricsConfig mc = new MetricsConfig(cf, prefix);
         LOG.debug(mc);
         return mc;
-      }
-      catch (ConfigurationException e) {
+      } catch (ConfigurationException e) {
         if (e.getMessage().startsWith("Cannot locate configuration")) {
           continue;
         }
@@ -198,8 +196,7 @@ class MetricsConfig extends SubsetConfig
       T plugin = (T) cls.newInstance();
       plugin.init(name.isEmpty() ? this : subset(name));
       return plugin;
-    }
-    catch (Exception e) {
+    } catch (Exception e) {
       throw new MetricsConfigException("Error creating plugin: "+ clsName, e);
     }
   }
@@ -229,8 +226,7 @@ class MetricsConfig extends SubsetConfig
           LOG.debug(jar);
           urls[i++] = new URL(jar);
         }
-      }
-      catch (Exception e) {
+      } catch (Exception e) {
         throw new MetricsConfigException(e);
       }
       if (LOG.isDebugEnabled()) {
@@ -276,8 +272,9 @@ class MetricsConfig extends SubsetConfig
     PrintStream ps = new PrintStream(buffer);
     PropertiesConfiguration tmp = new PropertiesConfiguration();
     tmp.copy(c);
-    try { tmp.save(ps); }
-    catch (Exception e) {
+    try {
+      tmp.save(ps);
+    } catch (Exception e) {
       throw new MetricsConfigException(e);
     }
     return buffer.toString();

Modified: hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/impl/MetricsRecordBuilderImpl.java
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/impl/MetricsRecordBuilderImpl.java?rev=1399950&r1=1399949&r2=1399950&view=diff
==============================================================================
--- hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/impl/MetricsRecordBuilderImpl.java (original)
+++ hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/impl/MetricsRecordBuilderImpl.java Fri Oct 19 02:25:55 2012
@@ -30,7 +30,16 @@ import org.apache.hadoop.metrics2.Metric
 import org.apache.hadoop.metrics2.MetricsRecordBuilder;
 import org.apache.hadoop.metrics2.MetricsTag;
 import org.apache.hadoop.metrics2.lib.Interns;
+import org.apache.hadoop.util.Time;
 
+/**
+ * {@link MetricsRecordBuilder} implementation used for building metrics records
+ * by the {@link MetricsCollector}. It provides the following functionality:
+ * <ul>
+ * <li>Allows configuring filters for metrics.
+ * </ul>
+ *
+ */
 class MetricsRecordBuilderImpl extends MetricsRecordBuilder {
   private final MetricsCollector parent;
   private final long timestamp;
@@ -40,11 +49,17 @@ class MetricsRecordBuilderImpl extends M
   private final MetricsFilter recordFilter, metricFilter;
   private final boolean acceptable;
 
+  /**
+   * @param parent {@link MetricsCollector} using this record builder
+   * @param info metrics information
+   * @param rf
+   * @param mf
+   * @param acceptable
+   */
   MetricsRecordBuilderImpl(MetricsCollector parent, MetricsInfo info,
-                           MetricsFilter rf, MetricsFilter mf,
-                           boolean acceptable) {
+      MetricsFilter rf, MetricsFilter mf, boolean acceptable) {
     this.parent = parent;
-    timestamp = System.currentTimeMillis();
+    timestamp = Time.now();
     recInfo = info;
     metrics = Lists.newArrayList();
     tags = Lists.newArrayList();

Modified: hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/impl/MetricsRecordImpl.java
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/impl/MetricsRecordImpl.java?rev=1399950&r1=1399949&r2=1399950&view=diff
==============================================================================
--- hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/impl/MetricsRecordImpl.java (original)
+++ hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/impl/MetricsRecordImpl.java Fri Oct 19 02:25:55 2012
@@ -37,7 +37,7 @@ class MetricsRecordImpl extends Abstract
 
   /**
    * Construct a metrics record
-   * @param info  {@link MetricInfo} of the record
+   * @param info  {@link MetricsInfo} of the record
    * @param timestamp of the record
    * @param tags  of the record
    * @param metrics of the record

Modified: hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/impl/MetricsSinkAdapter.java
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/impl/MetricsSinkAdapter.java?rev=1399950&r1=1399949&r2=1399950&view=diff
==============================================================================
--- hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/impl/MetricsSinkAdapter.java (original)
+++ hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/impl/MetricsSinkAdapter.java Fri Oct 19 02:25:55 2012
@@ -32,6 +32,7 @@ import org.apache.hadoop.metrics2.Metric
 import static org.apache.hadoop.metrics2.util.Contracts.*;
 import org.apache.hadoop.metrics2.MetricsFilter;
 import org.apache.hadoop.metrics2.MetricsSink;
+import org.apache.hadoop.util.Time;
 
 /**
  * An adapter class for metrics sink and associated filters
@@ -106,11 +107,9 @@ class MetricsSinkAdapter implements Sink
         retryDelay = firstRetryDelay;
         n = retryCount;
         inError = false;
-      }
-      catch (InterruptedException e) {
+      } catch (InterruptedException e) {
         LOG.info(name +" thread interrupted.");
-      }
-      catch (Exception e) {
+      } catch (Exception e) {
         if (n > 0) {
           int retryWindow = Math.max(0, 1000 / 2 * retryDelay - minDelay);
           int awhile = rng.nextInt(retryWindow) + minDelay;
@@ -123,8 +122,7 @@ class MetricsSinkAdapter implements Sink
             LOG.info(name +" thread interrupted while waiting for retry", e2);
           }
           --n;
-        }
-        else {
+        } else {
           if (!inError) {
             LOG.error("Got sink exception and over retry limit, "+
                       "suppressing further error messages", e);
@@ -158,7 +156,7 @@ class MetricsSinkAdapter implements Sink
     }
     if (ts > 0) {
       sink.flush();
-      latency.add(System.currentTimeMillis() - ts);
+      latency.add(Time.now() - ts);
     }
     LOG.debug("Done");
   }
@@ -173,8 +171,7 @@ class MetricsSinkAdapter implements Sink
     sinkThread.interrupt();
     try {
       sinkThread.join();
-    }
-    catch (InterruptedException e) {
+    } catch (InterruptedException e) {
       LOG.warn("Stop interrupted", e);
     }
   }

Modified: hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/impl/MetricsSourceAdapter.java
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/impl/MetricsSourceAdapter.java?rev=1399950&r1=1399949&r2=1399950&view=diff
==============================================================================
--- hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/impl/MetricsSourceAdapter.java (original)
+++ hadoop/common/branches/HDFS-2802/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/impl/MetricsSourceAdapter.java Fri Oct 19 02:25:55 2012
@@ -40,6 +40,8 @@ import org.apache.hadoop.metrics2.Metric
 import org.apache.hadoop.metrics2.MetricsTag;
 import static org.apache.hadoop.metrics2.impl.MetricsConfig.*;
 import org.apache.hadoop.metrics2.util.MBeans;
+import org.apache.hadoop.util.Time;
+
 import static org.apache.hadoop.metrics2.util.Contracts.*;
 
 /**
@@ -152,9 +154,9 @@ class MetricsSourceAdapter implements Dy
   private void updateJmxCache() {
     boolean getAllMetrics = false;
     synchronized(this) {
-      if (System.currentTimeMillis() - jmxCacheTS >= jmxCacheTTL) {
+      if (Time.now() - jmxCacheTS >= jmxCacheTTL) {
         // temporarilly advance the expiry while updating the cache
-        jmxCacheTS = System.currentTimeMillis() + jmxCacheTTL;
+        jmxCacheTS = Time.now() + jmxCacheTTL;
         if (lastRecs == null) {
           getAllMetrics = true;
         }
@@ -175,7 +177,7 @@ class MetricsSourceAdapter implements Dy
       if (oldCacheSize < newCacheSize) {
         updateInfoCache();
       }
-      jmxCacheTS = System.currentTimeMillis();
+      jmxCacheTS = Time.now();
       lastRecs = null;  // in case regular interval update is not running
     }
   }
@@ -190,8 +192,7 @@ class MetricsSourceAdapter implements Dy
     }
     try {
       source.getMetrics(builder, all);
-    }
-    catch (Exception e) {
+    } catch (Exception e) {
       LOG.error("Error getting metrics from source "+ name, e);
     }
     for (MetricsRecordBuilderImpl rb : builder) {