HBASE-16561 Add metrics about read/write/scan queue length and active read/write/scan handler count

Signed-off-by: zhangduo <zhangduo@apache.org>

hbase-hadoop-compat/src/main/java/org/apache/hadoop/hbase/ipc/MetricsHBaseServerSource.java

@@ -62,10 +62,25 @@ public interface MetricsHBaseServerSource extends BaseSource {
   String REPLICATION_QUEUE_DESC =
       "Number of calls in the replication call queue waiting to be run";
   String PRIORITY_QUEUE_DESC = "Number of calls in the priority call queue waiting to be run";
+  String WRITE_QUEUE_NAME = "numCallsInWriteQueue";
+  String WRITE_QUEUE_DESC = "Number of calls in the write call queue; " +
+    "parsed requests waiting in scheduler to be executed";
+  String READ_QUEUE_NAME = "numCallsInReadQueue";
+  String READ_QUEUE_DESC = "Number of calls in the read call queue; " +
+    "parsed requests waiting in scheduler to be executed";
+  String SCAN_QUEUE_NAME = "numCallsInScanQueue";
+  String SCAN_QUEUE_DESC = "Number of calls in the scan call queue; " +
+    "parsed requests waiting in scheduler to be executed";
   String NUM_OPEN_CONNECTIONS_NAME = "numOpenConnections";
   String NUM_OPEN_CONNECTIONS_DESC = "Number of open connections.";
   String NUM_ACTIVE_HANDLER_NAME = "numActiveHandler";
   String NUM_ACTIVE_HANDLER_DESC = "Number of active rpc handlers.";
+  String NUM_ACTIVE_WRITE_HANDLER_NAME = "numActiveWriteHandler";
+  String NUM_ACTIVE_WRITE_HANDLER_DESC = "Number of active write rpc handlers.";
+  String NUM_ACTIVE_READ_HANDLER_NAME = "numActiveReadHandler";
+  String NUM_ACTIVE_READ_HANDLER_DESC = "Number of active read rpc handlers.";
+  String NUM_ACTIVE_SCAN_HANDLER_NAME = "numActiveScanHandler";
+  String NUM_ACTIVE_SCAN_HANDLER_DESC = "Number of active scan rpc handlers.";
   String NUM_GENERAL_CALLS_DROPPED_NAME = "numGeneralCallsDropped";
   String NUM_GENERAL_CALLS_DROPPED_DESC = "Total number of calls in general queue which " +
     "were dropped by CoDel RPC executor";

hbase-hadoop-compat/src/main/java/org/apache/hadoop/hbase/ipc/MetricsHBaseServerWrapper.java

@@ -21,11 +21,30 @@ package org.apache.hadoop.hbase.ipc;
 
 public interface MetricsHBaseServerWrapper {
   long getTotalQueueSize();
+
   int getGeneralQueueLength();
+
   int getReplicationQueueLength();
+
   int getPriorityQueueLength();
+
   int getNumOpenConnections();
+
   int getActiveRpcHandlerCount();
+
   long getNumGeneralCallsDropped();
+
   long getNumLifoModeSwitches();
+
+  int getWriteQueueLength();
+
+  int getReadQueueLength();
+
+  int getScanQueueLength();
+
+  int getActiveWriteRpcHandlerCount();
+
+  int getActiveReadRpcHandlerCount();
+
+  int getActiveScanRpcHandlerCount();
 }

hbase-hadoop2-compat/src/main/java/org/apache/hadoop/hbase/ipc/MetricsHBaseServerSourceImpl.java

@@ -239,7 +239,19 @@ public class MetricsHBaseServerSourceImpl extends BaseSourceImpl
           .addCounter(Interns.info(NUM_GENERAL_CALLS_DROPPED_NAME,
               NUM_GENERAL_CALLS_DROPPED_DESC), wrapper.getNumGeneralCallsDropped())
           .addCounter(Interns.info(NUM_LIFO_MODE_SWITCHES_NAME,
-              NUM_LIFO_MODE_SWITCHES_DESC), wrapper.getNumLifoModeSwitches());
+              NUM_LIFO_MODE_SWITCHES_DESC), wrapper.getNumLifoModeSwitches())
+          .addGauge(Interns.info(WRITE_QUEUE_NAME, WRITE_QUEUE_DESC),
+              wrapper.getWriteQueueLength())
+          .addGauge(Interns.info(READ_QUEUE_NAME, READ_QUEUE_DESC),
+              wrapper.getReadQueueLength())
+          .addGauge(Interns.info(SCAN_QUEUE_NAME, SCAN_QUEUE_DESC),
+              wrapper.getScanQueueLength())
+          .addGauge(Interns.info(NUM_ACTIVE_WRITE_HANDLER_NAME, NUM_ACTIVE_WRITE_HANDLER_DESC),
+            wrapper.getActiveWriteRpcHandlerCount())
+          .addGauge(Interns.info(NUM_ACTIVE_READ_HANDLER_NAME, NUM_ACTIVE_READ_HANDLER_DESC),
+            wrapper.getActiveReadRpcHandlerCount())
+          .addGauge(Interns.info(NUM_ACTIVE_SCAN_HANDLER_NAME, NUM_ACTIVE_SCAN_HANDLER_DESC),
+            wrapper.getActiveScanRpcHandlerCount());
     }
 
     metricsRegistry.snapshot(mrb, all);

hbase-server/src/main/java/org/apache/hadoop/hbase/ipc/FastPathBalancedQueueRpcExecutor.java

@@ -21,6 +21,7 @@ import java.util.Deque;
 import java.util.concurrent.BlockingQueue;
 import java.util.concurrent.ConcurrentLinkedDeque;
 import java.util.concurrent.Semaphore;
+import java.util.concurrent.atomic.AtomicInteger;
 
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.hbase.Abortable;
@@ -56,8 +57,9 @@ public class FastPathBalancedQueueRpcExecutor extends BalancedQueueRpcExecutor {
 
   @Override
   protected Handler getHandler(String name, double handlerFailureThreshhold,
-      BlockingQueue<CallRunner> q) {
-    return new FastPathHandler(name, handlerFailureThreshhold, q, fastPathHandlerStack);
+      BlockingQueue<CallRunner> q, AtomicInteger activeHandlerCount) {
+    return new FastPathHandler(name, handlerFailureThreshhold, q, activeHandlerCount,
+        fastPathHandlerStack);
   }
 
   @Override
@@ -83,8 +85,9 @@ public class FastPathBalancedQueueRpcExecutor extends BalancedQueueRpcExecutor {
     private CallRunner loadedCallRunner;
 
     FastPathHandler(String name, double handlerFailureThreshhold, BlockingQueue<CallRunner> q,
+        final AtomicInteger activeHandlerCount,
         final Deque<FastPathHandler> fastPathHandlerStack) {
-      super(name, handlerFailureThreshhold, q);
+      super(name, handlerFailureThreshhold, q, activeHandlerCount);
       this.fastPathHandlerStack = fastPathHandlerStack;
     }
 

hbase-server/src/main/java/org/apache/hadoop/hbase/ipc/FifoRpcScheduler.java

@@ -118,4 +118,34 @@ public class FifoRpcScheduler extends RpcScheduler {
   public long getNumLifoModeSwitches() {
     return 0;
   }
+
+  @Override
+  public int getWriteQueueLength() {
+    return 0;
+  }
+
+  @Override
+  public int getReadQueueLength() {
+    return 0;
+  }
+
+  @Override
+  public int getScanQueueLength() {
+    return 0;
+  }
+
+  @Override
+  public int getActiveWriteRpcHandlerCount() {
+    return 0;
+  }
+
+  @Override
+  public int getActiveReadRpcHandlerCount() {
+    return 0;
+  }
+
+  @Override
+  public int getActiveScanRpcHandlerCount() {
+    return 0;
+  }
 }

hbase-server/src/main/java/org/apache/hadoop/hbase/ipc/MetricsHBaseServerWrapperImpl.java

@@ -94,4 +94,52 @@ public class MetricsHBaseServerWrapperImpl implements MetricsHBaseServerWrapper
     }
     return server.getScheduler().getNumLifoModeSwitches();
   }
+
+  @Override
+  public int getWriteQueueLength() {
+    if (!isServerStarted() || this.server.getScheduler() == null) {
+      return 0;
+    }
+    return server.getScheduler().getWriteQueueLength();
+  }
+
+  @Override
+  public int getReadQueueLength() {
+    if (!isServerStarted() || this.server.getScheduler() == null) {
+      return 0;
+    }
+    return server.getScheduler().getReadQueueLength();
+  }
+
+  @Override
+  public int getScanQueueLength() {
+    if (!isServerStarted() || this.server.getScheduler() == null) {
+      return 0;
+    }
+    return server.getScheduler().getScanQueueLength();
+  }
+
+  @Override
+  public int getActiveWriteRpcHandlerCount() {
+    if (!isServerStarted() || this.server.getScheduler() == null) {
+      return 0;
+    }
+    return server.getScheduler().getActiveWriteRpcHandlerCount();
+  }
+
+  @Override
+  public int getActiveReadRpcHandlerCount() {
+    if (!isServerStarted() || this.server.getScheduler() == null) {
+      return 0;
+    }
+    return server.getScheduler().getActiveReadRpcHandlerCount();
+  }
+
+  @Override
+  public int getActiveScanRpcHandlerCount() {
+    if (!isServerStarted() || this.server.getScheduler() == null) {
+      return 0;
+    }
+    return server.getScheduler().getActiveScanRpcHandlerCount();
+  }
 }

hbase-server/src/main/java/org/apache/hadoop/hbase/ipc/RWQueueRpcExecutor.java

@@ -19,12 +19,9 @@
 
 package org.apache.hadoop.hbase.ipc;
 
-import java.util.ArrayList;
-import java.util.List;
 import java.util.concurrent.BlockingQueue;
-import java.util.concurrent.LinkedBlockingQueue;
+import java.util.concurrent.atomic.AtomicInteger;
 
-import org.apache.commons.lang.ArrayUtils;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.conf.Configuration;
@@ -39,7 +36,6 @@ import org.apache.hadoop.hbase.shaded.protobuf.generated.RegionServerStatusProto
 import org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.RegionAction;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.ClientProtos.ScanRequest;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.RPCProtos.RequestHeader;
-import org.apache.hadoop.hbase.util.ReflectionUtils;
 import org.apache.hadoop.hbase.shaded.com.google.protobuf.Message;
 
 /**
@@ -67,6 +63,10 @@ public class RWQueueRpcExecutor extends RpcExecutor {
   private final int numReadQueues;
   private final int numScanQueues;
 
+  private final AtomicInteger activeWriteHandlerCount = new AtomicInteger(0);
+  private final AtomicInteger activeReadHandlerCount = new AtomicInteger(0);
+  private final AtomicInteger activeScanHandlerCount = new AtomicInteger(0);
+
   public RWQueueRpcExecutor(final String name, final int handlerCount, final int maxQueueLength,
       final PriorityFunction priority, final Configuration conf, final Abortable abortable) {
     super(name, handlerCount, maxQueueLength, priority, conf, abortable);
@@ -117,11 +117,13 @@ public class RWQueueRpcExecutor extends RpcExecutor {
 
   @Override
   protected void startHandlers(final int port) {
-    startHandlers(".write", writeHandlersCount, queues, 0, numWriteQueues, port);
-    startHandlers(".read", readHandlersCount, queues, numWriteQueues, numReadQueues, port);
+    startHandlers(".write", writeHandlersCount, queues, 0, numWriteQueues, port,
+      activeWriteHandlerCount);
+    startHandlers(".read", readHandlersCount, queues, numWriteQueues, numReadQueues, port,
+      activeReadHandlerCount);
     if (numScanQueues > 0) {
       startHandlers(".scan", scanHandlersCount, queues, numWriteQueues + numReadQueues,
-        numScanQueues, port);
+        numScanQueues, port, activeScanHandlerCount);
     }
   }
 
@@ -144,6 +146,55 @@ public class RWQueueRpcExecutor extends RpcExecutor {
     return queue.offer(callTask);
   }
 
+  @Override
+  public int getWriteQueueLength() {
+    int length = 0;
+    for (int i = 0; i < numWriteQueues; i++) {
+      length += queues.get(i).size();
+    }
+    return length;
+  }
+
+  @Override
+  public int getReadQueueLength() {
+    int length = 0;
+    for (int i = numWriteQueues; i < (numWriteQueues + numReadQueues); i++) {
+      length += queues.get(i).size();
+    }
+    return length;
+  }
+
+  @Override
+  public int getScanQueueLength() {
+    int length = 0;
+    for (int i = numWriteQueues + numReadQueues;
+        i < (numWriteQueues + numReadQueues + numScanQueues); i++) {
+      length += queues.get(i).size();
+    }
+    return length;
+  }
+
+  @Override
+  public int getActiveHandlerCount() {
+    return activeWriteHandlerCount.get() + activeReadHandlerCount.get()
+        + activeScanHandlerCount.get();
+  }
+
+  @Override
+  public int getActiveWriteHandlerCount() {
+    return activeWriteHandlerCount.get();
+  }
+
+  @Override
+  public int getActiveReadHandlerCount() {
+    return activeReadHandlerCount.get();
+  }
+
+  @Override
+  public int getActiveScanHandlerCount() {
+    return activeScanHandlerCount.get();
+  }
+
   private boolean isWriteRequest(final RequestHeader header, final Message param) {
     // TODO: Is there a better way to do this?
     if (param instanceof MultiRequest) {

hbase-server/src/main/java/org/apache/hadoop/hbase/ipc/RpcExecutor.java

@@ -19,7 +19,6 @@
 package org.apache.hadoop.hbase.ipc;
 
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.Comparator;
 import java.util.List;
 import java.util.Locale;
@@ -175,19 +174,6 @@ public abstract class RpcExecutor {
     }
   }
 
-  public int getActiveHandlerCount() {
-    return activeHandlerCount.get();
-  }
-
-  /** Returns the length of the pending queue */
-  public int getQueueLength() {
-    int length = 0;
-    for (final BlockingQueue<CallRunner> queue: queues) {
-      length += queue.size();
-    }
-    return length;
-  }
-
   /** Add the request to the executor queue */
   public abstract boolean dispatch(final CallRunner callTask) throws InterruptedException;
 
@@ -198,15 +184,15 @@ public abstract class RpcExecutor {
 
   protected void startHandlers(final int port) {
     List<BlockingQueue<CallRunner>> callQueues = getQueues();
-    startHandlers(null, handlerCount, callQueues, 0, callQueues.size(), port);
+    startHandlers(null, handlerCount, callQueues, 0, callQueues.size(), port, activeHandlerCount);
   }
 
   /**
    * Override if providing alternate Handler implementation.
    */
   protected Handler getHandler(final String name, final double handlerFailureThreshhold,
-      final BlockingQueue<CallRunner> q) {
-    return new Handler(name, handlerFailureThreshhold, q);
+      final BlockingQueue<CallRunner> q, final AtomicInteger activeHandlerCount) {
+    return new Handler(name, handlerFailureThreshhold, q, activeHandlerCount);
   }
 
   /**
@@ -214,7 +200,7 @@ public abstract class RpcExecutor {
    */
   protected void startHandlers(final String nameSuffix, final int numHandlers,
       final List<BlockingQueue<CallRunner>> callQueues, final int qindex, final int qsize,
-      final int port) {
+      final int port, final AtomicInteger activeHandlerCount) {
     final String threadPrefix = name + Strings.nullToEmpty(nameSuffix);
     double handlerFailureThreshhold = conf == null ? 1.0 : conf.getDouble(
       HConstants.REGION_SERVER_HANDLER_ABORT_ON_ERROR_PERCENT,
@@ -223,7 +209,8 @@ public abstract class RpcExecutor {
       final int index = qindex + (i % qsize);
       String name = "RpcServer." + threadPrefix + ".handler=" + handlers.size() + ",queue=" + index
           + ",port=" + port;
-      Handler handler = getHandler(name, handlerFailureThreshhold, callQueues.get(index));
+      Handler handler = getHandler(name, handlerFailureThreshhold, callQueues.get(index),
+        activeHandlerCount);
       handler.start();
       LOG.debug("Started " + name);
       handlers.add(handler);
@@ -241,12 +228,16 @@ public abstract class RpcExecutor {
 
     final double handlerFailureThreshhold;
 
+    // metrics (shared with other handlers)
+    final AtomicInteger activeHandlerCount;
+
     Handler(final String name, final double handlerFailureThreshhold,
-        final BlockingQueue<CallRunner> q) {
+        final BlockingQueue<CallRunner> q, final AtomicInteger activeHandlerCount) {
       super(name);
       setDaemon(true);
       this.q = q;
       this.handlerFailureThreshhold = handlerFailureThreshhold;
+      this.activeHandlerCount = activeHandlerCount;
     }
 
     /**
@@ -282,7 +273,7 @@ public abstract class RpcExecutor {
       MonitoredRPCHandler status = RpcServer.getStatus();
       cr.setStatus(status);
       try {
-        activeHandlerCount.incrementAndGet();
+        this.activeHandlerCount.incrementAndGet();
         cr.run();
       } catch (Throwable e) {
         if (e instanceof Error) {
@@ -305,7 +296,7 @@ public abstract class RpcExecutor {
           LOG.warn("Handler  exception " + StringUtils.stringifyException(e));
         }
       } finally {
-        activeHandlerCount.decrementAndGet();
+        this.activeHandlerCount.decrementAndGet();
       }
     }
   }
@@ -400,6 +391,43 @@ public abstract class RpcExecutor {
     return numLifoModeSwitches.get();
   }
 
+  public int getActiveHandlerCount() {
+    return activeHandlerCount.get();
+  }
+
+  public int getActiveWriteHandlerCount() {
+    return 0;
+  }
+
+  public int getActiveReadHandlerCount() {
+    return 0;
+  }
+
+  public int getActiveScanHandlerCount() {
+    return 0;
+  }
+
+  /** Returns the length of the pending queue */
+  public int getQueueLength() {
+    int length = 0;
+    for (final BlockingQueue<CallRunner> queue: queues) {
+      length += queue.size();
+    }
+    return length;
+  }
+
+  public int getReadQueueLength() {
+    return 0;
+  }
+
+  public int getScanQueueLength() {
+    return 0;
+  }
+
+  public int getWriteQueueLength() {
+    return 0;
+  }
+
   public String getName() {
     return this.name;
   }

hbase-server/src/main/java/org/apache/hadoop/hbase/ipc/RpcScheduler.java

@@ -89,4 +89,22 @@ public abstract class RpcScheduler {
    * in the period of overloade we serve last requests first); returns 0 otherwise.
    */
   public abstract long getNumLifoModeSwitches();
+
+  /** Retrieves length of the write queue for metrics when use RWQueueRpcExecutor. */
+  public abstract int getWriteQueueLength();
+
+  /** Retrieves length of the read queue for metrics when use RWQueueRpcExecutor. */
+  public abstract int getReadQueueLength();
+
+  /** Retrieves length of the scan queue for metrics when use RWQueueRpcExecutor. */
+  public abstract int getScanQueueLength();
+
+  /** Retrieves the number of active write rpc handler when use RWQueueRpcExecutor. */
+  public abstract int getActiveWriteRpcHandlerCount();
+
+  /** Retrieves the number of active write rpc handler when use RWQueueRpcExecutor. */
+  public abstract int getActiveReadRpcHandlerCount();
+
+  /** Retrieves the number of active write rpc handler when use RWQueueRpcExecutor. */
+  public abstract int getActiveScanRpcHandlerCount();
 }

hbase-server/src/main/java/org/apache/hadoop/hbase/ipc/SimpleRpcScheduler.java

@@ -17,11 +17,6 @@
  */
 package org.apache.hadoop.hbase.ipc;
 
-
-import java.util.Comparator;
-import java.util.concurrent.BlockingQueue;
-import java.util.concurrent.atomic.AtomicLong;
-
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.conf.Configuration;
@@ -31,7 +26,6 @@ import org.apache.hadoop.hbase.HConstants;
 import org.apache.hadoop.hbase.classification.InterfaceAudience;
 import org.apache.hadoop.hbase.classification.InterfaceStability;
 import org.apache.hadoop.hbase.conf.ConfigurationObserver;
-import org.apache.hadoop.hbase.util.BoundedPriorityBlockingQueue;
 
 /**
  * The default scheduler. Configurable. Maintains isolated handler pools for general ('default'),
@@ -205,5 +199,35 @@ public class SimpleRpcScheduler extends RpcScheduler implements ConfigurationObs
   public long getNumLifoModeSwitches() {
     return callExecutor.getNumLifoModeSwitches();
   }
+
+  @Override
+  public int getWriteQueueLength() {
+    return callExecutor.getWriteQueueLength();
+  }
+
+  @Override
+  public int getReadQueueLength() {
+    return callExecutor.getReadQueueLength();
+  }
+
+  @Override
+  public int getScanQueueLength() {
+    return callExecutor.getScanQueueLength();
+  }
+
+  @Override
+  public int getActiveWriteRpcHandlerCount() {
+    return callExecutor.getActiveWriteHandlerCount();
+  }
+
+  @Override
+  public int getActiveReadRpcHandlerCount() {
+    return callExecutor.getActiveReadHandlerCount();
+  }
+
+  @Override
+  public int getActiveScanRpcHandlerCount() {
+    return callExecutor.getActiveScanHandlerCount();
+  }
 }
 

hbase-server/src/test/java/org/apache/hadoop/hbase/ipc/DelegatingRpcScheduler.java

@@ -73,4 +73,34 @@ public class DelegatingRpcScheduler extends RpcScheduler {
   public long getNumLifoModeSwitches() {
     return delegate.getNumLifoModeSwitches();
   }
+
+  @Override
+  public int getWriteQueueLength() {
+    return 0;
+  }
+
+  @Override
+  public int getReadQueueLength() {
+    return 0;
+  }
+
+  @Override
+  public int getScanQueueLength() {
+    return 0;
+  }
+
+  @Override
+  public int getActiveWriteRpcHandlerCount() {
+    return 0;
+  }
+
+  @Override
+  public int getActiveReadRpcHandlerCount() {
+    return 0;
+  }
+
+  @Override
+  public int getActiveScanRpcHandlerCount() {
+    return 0;
+  }
 }

hbase-server/src/test/java/org/apache/hadoop/hbase/ipc/MetricsHBaseServerWrapperStub.java

@@ -58,4 +58,34 @@ public class MetricsHBaseServerWrapperStub implements MetricsHBaseServerWrapper{
   public long getNumLifoModeSwitches() {
     return 5;
   }
+
+  @Override
+  public int getWriteQueueLength() {
+    return 50;
+  }
+
+  @Override
+  public int getReadQueueLength() {
+    return 50;
+  }
+
+  @Override
+  public int getScanQueueLength() {
+    return 2;
+  }
+
+  @Override
+  public int getActiveWriteRpcHandlerCount() {
+    return 50;
+  }
+
+  @Override
+  public int getActiveReadRpcHandlerCount() {
+    return 50;
+  }
+
+  @Override
+  public int getActiveScanRpcHandlerCount() {
+    return 6;
+  }
 }

hbase-server/src/test/java/org/apache/hadoop/hbase/ipc/TestRpcMetrics.java

@@ -46,7 +46,6 @@ public class TestRpcMetrics {
     MetricsHBaseServer rsMetrics = new MetricsHBaseServer("HRegionServer", new MetricsHBaseServerWrapperStub());
     MetricsHBaseServerSource rsSource = rsMetrics.getMetricsSource();
 
-
     assertEquals("master", masterSource.getMetricsContext());
     assertEquals("regionserver", rsSource.getMetricsContext());
 
@@ -71,6 +70,12 @@ public class TestRpcMetrics {
     HELPER.assertGauge("numCallsInPriorityQueue", 104, serverSource);
     HELPER.assertGauge("numOpenConnections", 105, serverSource);
     HELPER.assertGauge("numActiveHandler", 106, serverSource);
+    HELPER.assertGauge("numActiveWriteHandler", 50, serverSource);
+    HELPER.assertGauge("numActiveReadHandler", 50, serverSource);
+    HELPER.assertGauge("numActiveScanHandler", 6, serverSource);
+    HELPER.assertGauge("numCallsInWriteQueue", 50, serverSource);
+    HELPER.assertGauge("numCallsInReadQueue", 50, serverSource);
+    HELPER.assertGauge("numCallsInScanQueue", 2, serverSource);
   }
 
   /**