HDFS-5188. In BlockPlacementPolicy, reduce the number of chooseTarget(..) methods; replace HashMap with Map in parameter declarations and cleanup some related code.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1523400 13f79535-47bb-0310-9956-ffa450edef68

hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

@@ -275,6 +275,10 @@ Release 2.3.0 - UNRELEASED
     HDFS-4096. Add snapshot information to namenode WebUI. (Haohui Mai via 
     jing9)
 
+    HDFS-5188. In BlockPlacementPolicy, reduce the number of chooseTarget(..)
+    methods; replace HashMap with Map in parameter declarations and cleanup
+    some related code.  (szetszwo)
+
   OPTIMIZATIONS
 
   BUG FIXES

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSConfigKeys.java

@@ -20,6 +20,7 @@ package org.apache.hadoop.hdfs;
 
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.fs.CommonConfigurationKeys;
+import org.apache.hadoop.hdfs.server.blockmanagement.BlockPlacementPolicyDefault;
 
 /** 
  * This class contains constants for configuration keys used
@@ -348,6 +349,8 @@ public class DFSConfigKeys extends CommonConfigurationKeys {
   public static final String  DFS_BLOCK_ACCESS_TOKEN_LIFETIME_KEY = "dfs.block.access.token.lifetime";
   public static final long    DFS_BLOCK_ACCESS_TOKEN_LIFETIME_DEFAULT = 600L;
 
+  public static final String DFS_BLOCK_REPLICATOR_CLASSNAME_KEY = "dfs.block.replicator.classname";
+  public static final Class<BlockPlacementPolicyDefault> DFS_BLOCK_REPLICATOR_CLASSNAME_DEFAULT = BlockPlacementPolicyDefault.class;
   public static final String  DFS_REPLICATION_MAX_KEY = "dfs.replication.max";
   public static final int     DFS_REPLICATION_MAX_DEFAULT = 512;
   public static final String  DFS_DF_INTERVAL_KEY = "dfs.df.interval";

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockManager.java

@@ -1256,8 +1256,7 @@ public class BlockManager {
       namesystem.writeUnlock();
     }
 
-    HashMap<Node, Node> excludedNodes
-        = new HashMap<Node, Node>();
+    final Map<Node, Node> excludedNodes = new HashMap<Node, Node>();
     for(ReplicationWork rw : work){
       // Exclude all of the containing nodes from being targets.
       // This list includes decommissioning or corrupt nodes.
@@ -1269,9 +1268,7 @@ public class BlockManager {
       // choose replication targets: NOT HOLDING THE GLOBAL LOCK
       // It is costly to extract the filename for which chooseTargets is called,
       // so for now we pass in the block collection itself.
-      rw.targets = blockplacement.chooseTarget(rw.bc,
-          rw.additionalReplRequired, rw.srcNode, rw.liveReplicaNodes,
-          excludedNodes, rw.block.getNumBytes());
+      rw.chooseTargets(blockplacement, excludedNodes);
     }
 
     namesystem.writeLock();
@@ -3249,6 +3246,13 @@ assert storedBlock.findDatanode(dn) < 0 : "Block " + block
       this.priority = priority;
       this.targets = null;
     }
+    
+    private void chooseTargets(BlockPlacementPolicy blockplacement,
+        Map<Node, Node> excludedNodes) {
+      targets = blockplacement.chooseTarget(bc.getName(),
+          additionalReplRequired, srcNode, liveReplicaNodes, false,
+          excludedNodes, block.getNumBytes());
+    }
   }
 
   /**

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockPlacementPolicy.java

@@ -19,7 +19,6 @@ package org.apache.hadoop.hdfs.server.blockmanagement;
 
 import java.util.ArrayList;
 import java.util.Collection;
-import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
@@ -27,6 +26,7 @@ import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.hdfs.DFSConfigKeys;
 import org.apache.hadoop.hdfs.protocol.Block;
 import org.apache.hadoop.hdfs.protocol.DatanodeInfo;
 import org.apache.hadoop.hdfs.protocol.LocatedBlock;
@@ -51,25 +51,6 @@ public abstract class BlockPlacementPolicy {
     }
   }
     
-  /**
-   * choose <i>numOfReplicas</i> data nodes for <i>writer</i> 
-   * to re-replicate a block with size <i>blocksize</i> 
-   * If not, return as many as we can.
-   * 
-   * @param srcPath the file to which this chooseTargets is being invoked. 
-   * @param numOfReplicas additional number of replicas wanted.
-   * @param writer the writer's machine, null if not in the cluster.
-   * @param chosenNodes datanodes that have been chosen as targets.
-   * @param blocksize size of the data to be written.
-   * @return array of DatanodeDescriptor instances chosen as target 
-   * and sorted as a pipeline.
-   */
-  abstract DatanodeDescriptor[] chooseTarget(String srcPath,
-                                             int numOfReplicas,
-                                             DatanodeDescriptor writer,
-                                             List<DatanodeDescriptor> chosenNodes,
-                                             long blocksize);
-
   /**
    * choose <i>numOfReplicas</i> data nodes for <i>writer</i> 
    * to re-replicate a block with size <i>blocksize</i> 
@@ -90,34 +71,8 @@ public abstract class BlockPlacementPolicy {
                                              DatanodeDescriptor writer,
                                              List<DatanodeDescriptor> chosenNodes,
                                              boolean returnChosenNodes,
-                                             HashMap<Node, Node> excludedNodes,
+                                             Map<Node, Node> excludedNodes,
                                              long blocksize);
-
-  /**
-   * choose <i>numOfReplicas</i> data nodes for <i>writer</i>
-   * If not, return as many as we can.
-   * The base implemenatation extracts the pathname of the file from the
-   * specified srcBC, but this could be a costly operation depending on the
-   * file system implementation. Concrete implementations of this class should
-   * override this method to avoid this overhead.
-   * 
-   * @param srcBC block collection of file for which chooseTarget is invoked.
-   * @param numOfReplicas additional number of replicas wanted.
-   * @param writer the writer's machine, null if not in the cluster.
-   * @param chosenNodes datanodes that have been chosen as targets.
-   * @param blocksize size of the data to be written.
-   * @return array of DatanodeDescriptor instances chosen as target 
-   * and sorted as a pipeline.
-   */
-  DatanodeDescriptor[] chooseTarget(BlockCollection srcBC,
-                                    int numOfReplicas,
-                                    DatanodeDescriptor writer,
-                                    List<DatanodeDescriptor> chosenNodes,
-                                    HashMap<Node, Node> excludedNodes,
-                                    long blocksize) {
-    return chooseTarget(srcBC.getName(), numOfReplicas, writer,
-                        chosenNodes, false, excludedNodes, blocksize);
-  }
   
   /**
    * Same as {@link #chooseTarget(String, int, DatanodeDescriptor, List, boolean, 
@@ -128,7 +83,7 @@ public abstract class BlockPlacementPolicy {
    */
   DatanodeDescriptor[] chooseTarget(String src,
       int numOfReplicas, DatanodeDescriptor writer,
-      HashMap<Node, Node> excludedNodes,
+      Map<Node, Node> excludedNodes,
       long blocksize, List<DatanodeDescriptor> favoredNodes) {
     // This class does not provide the functionality of placing
     // a block in favored datanodes. The implementations of this class
@@ -183,7 +138,7 @@ public abstract class BlockPlacementPolicy {
     
   /**
    * Get an instance of the configured Block Placement Policy based on the
-   * value of the configuration paramater dfs.block.replicator.classname.
+   * the configuration property {@link DFS_BLOCK_REPLICATOR_CLASSNAME_KEY}.
    * 
    * @param conf the configuration to be used
    * @param stats an object that is used to retrieve the load on the cluster
@@ -193,12 +148,12 @@ public abstract class BlockPlacementPolicy {
   public static BlockPlacementPolicy getInstance(Configuration conf, 
                                                  FSClusterStats stats,
                                                  NetworkTopology clusterMap) {
-    Class<? extends BlockPlacementPolicy> replicatorClass =
-                      conf.getClass("dfs.block.replicator.classname",
-                                    BlockPlacementPolicyDefault.class,
-                                    BlockPlacementPolicy.class);
-    BlockPlacementPolicy replicator = (BlockPlacementPolicy) ReflectionUtils.newInstance(
-                                                             replicatorClass, conf);
+    final Class<? extends BlockPlacementPolicy> replicatorClass = conf.getClass(
+        DFSConfigKeys.DFS_BLOCK_REPLICATOR_CLASSNAME_KEY,
+        DFSConfigKeys.DFS_BLOCK_REPLICATOR_CLASSNAME_DEFAULT,
+        BlockPlacementPolicy.class);
+    final BlockPlacementPolicy replicator = ReflectionUtils.newInstance(
+        replicatorClass, conf);
     replicator.initialize(conf, stats, clusterMap);
     return replicator;
   }

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockPlacementPolicyDefault.java

@@ -22,8 +22,8 @@ import static org.apache.hadoop.util.Time.now;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashMap;
-import java.util.Iterator;
 import java.util.List;
+import java.util.Map;
 import java.util.Set;
 import java.util.TreeSet;
 
@@ -57,6 +57,14 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
     "For more information, please enable DEBUG log level on "
     + BlockPlacementPolicy.class.getName();
 
+  private static final ThreadLocal<StringBuilder> debugLoggingBuilder
+      = new ThreadLocal<StringBuilder>() {
+        @Override
+        protected StringBuilder initialValue() {
+          return new StringBuilder();
+        }
+      };
+
   protected boolean considerLoad; 
   private boolean preferLocalNode = true;
   protected NetworkTopology clusterMap;
@@ -95,40 +103,25 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
         DFSConfigKeys.DFS_NAMENODE_STALE_DATANODE_INTERVAL_DEFAULT);
   }
 
-  protected ThreadLocal<StringBuilder> threadLocalBuilder =
-    new ThreadLocal<StringBuilder>() {
-    @Override
-    protected StringBuilder initialValue() {
-      return new StringBuilder();
-    }
-  };
-
-  @Override
-  public DatanodeDescriptor[] chooseTarget(String srcPath,
-                                    int numOfReplicas,
-                                    DatanodeDescriptor writer,
-                                    List<DatanodeDescriptor> chosenNodes,
-                                    long blocksize) {
-    return chooseTarget(numOfReplicas, writer, chosenNodes, false,
-        null, blocksize);
-  }
-
   @Override
   public DatanodeDescriptor[] chooseTarget(String srcPath,
                                     int numOfReplicas,
                                     DatanodeDescriptor writer,
                                     List<DatanodeDescriptor> chosenNodes,
                                     boolean returnChosenNodes,
-                                    HashMap<Node, Node> excludedNodes,
+                                    Map<Node, Node> excludedNodes,
                                     long blocksize) {
     return chooseTarget(numOfReplicas, writer, chosenNodes, returnChosenNodes,
         excludedNodes, blocksize);
   }
 
   @Override
-  DatanodeDescriptor[] chooseTarget(String src, int numOfReplicas,
-      DatanodeDescriptor writer, HashMap<Node, Node> excludedNodes,
-      long blocksize, List<DatanodeDescriptor> favoredNodes) {
+  DatanodeDescriptor[] chooseTarget(String src,
+      int numOfReplicas,
+      DatanodeDescriptor writer,
+      Map<Node, Node> excludedNodes,
+      long blocksize,
+      List<DatanodeDescriptor> favoredNodes) {
     try {
       if (favoredNodes == null || favoredNodes.size() == 0) {
         // Favored nodes not specified, fall back to regular block placement.
@@ -137,7 +130,7 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
             excludedNodes, blocksize);
       }
 
-      HashMap<Node, Node> favoriteAndExcludedNodes = excludedNodes == null ?
+      Map<Node, Node> favoriteAndExcludedNodes = excludedNodes == null ?
           new HashMap<Node, Node>() : new HashMap<Node, Node>(excludedNodes);
 
       // Choose favored nodes
@@ -181,14 +174,14 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
   }
 
   /** This is the implementation. */
-  DatanodeDescriptor[] chooseTarget(int numOfReplicas,
+  private DatanodeDescriptor[] chooseTarget(int numOfReplicas,
                                     DatanodeDescriptor writer,
                                     List<DatanodeDescriptor> chosenNodes,
                                     boolean returnChosenNodes,
-                                    HashMap<Node, Node> excludedNodes,
+                                    Map<Node, Node> excludedNodes,
                                     long blocksize) {
     if (numOfReplicas == 0 || clusterMap.getNumOfLeaves()==0) {
-      return new DatanodeDescriptor[0];
+      return DatanodeDescriptor.EMPTY_ARRAY;
     }
       
     if (excludedNodes == null) {
@@ -204,7 +197,6 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
     for (DatanodeDescriptor node:chosenNodes) {
       // add localMachine and related nodes to excludedNodes
       addToExcludedNodes(node, excludedNodes);
-      adjustExcludedNodes(excludedNodes, node);
     }
       
     if (!clusterMap.contains(writer)) {
@@ -239,7 +231,7 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
   /* choose <i>numOfReplicas</i> from all data nodes */
   private DatanodeDescriptor chooseTarget(int numOfReplicas,
                                           DatanodeDescriptor writer,
-                                          HashMap<Node, Node> excludedNodes,
+                                          Map<Node, Node> excludedNodes,
                                           long blocksize,
                                           int maxNodesPerRack,
                                           List<DatanodeDescriptor> results,
@@ -256,7 +248,7 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
     }
 
     // Keep a copy of original excludedNodes
-    final HashMap<Node, Node> oldExcludedNodes = avoidStaleNodes ? 
+    final Map<Node, Node> oldExcludedNodes = avoidStaleNodes ? 
         new HashMap<Node, Node>(excludedNodes) : null;
     try {
       if (numOfResults == 0) {
@@ -316,19 +308,19 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
     return writer;
   }
     
-  /* choose <i>localMachine</i> as the target.
+  /**
+   * Choose <i>localMachine</i> as the target.
    * if <i>localMachine</i> is not available, 
    * choose a node on the same rack
    * @return the chosen node
    */
-  protected DatanodeDescriptor chooseLocalNode(
-                                             DatanodeDescriptor localMachine,
-                                             HashMap<Node, Node> excludedNodes,
+  protected DatanodeDescriptor chooseLocalNode(DatanodeDescriptor localMachine,
+                                             Map<Node, Node> excludedNodes,
                                              long blocksize,
                                              int maxNodesPerRack,
                                              List<DatanodeDescriptor> results,
                                              boolean avoidStaleNodes)
-    throws NotEnoughReplicasException {
+      throws NotEnoughReplicasException {
     // if no local machine, randomly choose one node
     if (localMachine == null)
       return chooseRandom(NodeBase.ROOT, excludedNodes, blocksize,
@@ -337,11 +329,8 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
       // otherwise try local machine first
       Node oldNode = excludedNodes.put(localMachine, localMachine);
       if (oldNode == null) { // was not in the excluded list
-        if (isGoodTarget(localMachine, blocksize, maxNodesPerRack, false,
-            results, avoidStaleNodes)) {
-          results.add(localMachine);
-          // add localMachine and related nodes to excludedNode
-          addToExcludedNodes(localMachine, excludedNodes);
+        if (addIfIsGoodTarget(localMachine, excludedNodes, blocksize,
+            maxNodesPerRack, false, results, avoidStaleNodes) >= 0) {
           return localMachine;
         }
       } 
@@ -358,26 +347,26 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
    * @return number of new excluded nodes
    */
   protected int addToExcludedNodes(DatanodeDescriptor localMachine,
-      HashMap<Node, Node> excludedNodes) {
+      Map<Node, Node> excludedNodes) {
     Node node = excludedNodes.put(localMachine, localMachine);
     return node == null?1:0;
   }
 
-  /* choose one node from the rack that <i>localMachine</i> is on.
+  /**
+   * Choose one node from the rack that <i>localMachine</i> is on.
    * if no such node is available, choose one node from the rack where
    * a second replica is on.
    * if still no such node is available, choose a random node 
    * in the cluster.
    * @return the chosen node
    */
-  protected DatanodeDescriptor chooseLocalRack(
-                                             DatanodeDescriptor localMachine,
-                                             HashMap<Node, Node> excludedNodes,
+  protected DatanodeDescriptor chooseLocalRack(DatanodeDescriptor localMachine,
+                                             Map<Node, Node> excludedNodes,
                                              long blocksize,
                                              int maxNodesPerRack,
                                              List<DatanodeDescriptor> results,
                                              boolean avoidStaleNodes)
-    throws NotEnoughReplicasException {
+      throws NotEnoughReplicasException {
     // no local machine, so choose a random machine
     if (localMachine == null) {
       return chooseRandom(NodeBase.ROOT, excludedNodes, blocksize,
@@ -391,9 +380,7 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
     } catch (NotEnoughReplicasException e1) {
       // find the second replica
       DatanodeDescriptor newLocal=null;
-      for(Iterator<DatanodeDescriptor> iter=results.iterator();
-          iter.hasNext();) {
-        DatanodeDescriptor nextNode = iter.next();
+      for(DatanodeDescriptor nextNode : results) {
         if (nextNode != localMachine) {
           newLocal = nextNode;
           break;
@@ -416,7 +403,8 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
     }
   }
     
-  /* choose <i>numOfReplicas</i> nodes from the racks 
+  /** 
+   * Choose <i>numOfReplicas</i> nodes from the racks 
    * that <i>localMachine</i> is NOT on.
    * if not enough nodes are available, choose the remaining ones 
    * from the local rack
@@ -424,12 +412,12 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
     
   protected void chooseRemoteRack(int numOfReplicas,
                                 DatanodeDescriptor localMachine,
-                                HashMap<Node, Node> excludedNodes,
+                                Map<Node, Node> excludedNodes,
                                 long blocksize,
                                 int maxReplicasPerRack,
                                 List<DatanodeDescriptor> results,
                                 boolean avoidStaleNodes)
-    throws NotEnoughReplicasException {
+                                    throws NotEnoughReplicasException {
     int oldNumOfReplicas = results.size();
     // randomly choose one node from remote racks
     try {
@@ -443,91 +431,59 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
     }
   }
 
-  /* Randomly choose one target from <i>nodes</i>.
-   * @return the chosen node
+  /**
+   * Randomly choose one target from the given <i>scope</i>.
+   * @return the chosen node, if there is any.
    */
-  protected DatanodeDescriptor chooseRandom(
-                                          String nodes,
-                                          HashMap<Node, Node> excludedNodes,
-                                          long blocksize,
-                                          int maxNodesPerRack,
-                                          List<DatanodeDescriptor> results,
-                                          boolean avoidStaleNodes) 
-    throws NotEnoughReplicasException {
-    int numOfAvailableNodes =
-      clusterMap.countNumOfAvailableNodes(nodes, excludedNodes.keySet());
-    StringBuilder builder = null;
-    if (LOG.isDebugEnabled()) {
-      builder = threadLocalBuilder.get();
-      builder.setLength(0);
-      builder.append("[");
-    }
-    boolean badTarget = false;
-    while(numOfAvailableNodes > 0) {
-      DatanodeDescriptor chosenNode = 
-        (DatanodeDescriptor)(clusterMap.chooseRandom(nodes));
-
-      Node oldNode = excludedNodes.put(chosenNode, chosenNode);
-      if (oldNode == null) { // chosenNode was not in the excluded list
-        numOfAvailableNodes--;
-        if (isGoodTarget(chosenNode, blocksize, 
-                maxNodesPerRack, results, avoidStaleNodes)) {
-          results.add(chosenNode);
-          // add chosenNode and related nodes to excludedNode
-          addToExcludedNodes(chosenNode, excludedNodes);
-          adjustExcludedNodes(excludedNodes, chosenNode);
-          return chosenNode;
-        } else {
-          badTarget = true;
-        }
-      }
-    }
-
-    String detail = enableDebugLogging;
-    if (LOG.isDebugEnabled()) {
-      if (badTarget && builder != null) {
-        detail = builder.append("]").toString();
-        builder.setLength(0);
-      } else detail = "";
-    }
-    throw new NotEnoughReplicasException(detail);
+  protected DatanodeDescriptor chooseRandom(String scope,
+      Map<Node, Node> excludedNodes,
+      long blocksize,
+      int maxNodesPerRack,
+      List<DatanodeDescriptor> results,
+      boolean avoidStaleNodes)
+          throws NotEnoughReplicasException {
+    return chooseRandom(1, scope, excludedNodes, blocksize, maxNodesPerRack,
+        results, avoidStaleNodes);
   }
-    
-  /* Randomly choose <i>numOfReplicas</i> targets from <i>nodes</i>.
+
+  /**
+   * Randomly choose <i>numOfReplicas</i> targets from the given <i>scope</i>.
+   * @return the first chosen node, if there is any.
    */
-  protected void chooseRandom(int numOfReplicas,
-                            String nodes,
-                            HashMap<Node, Node> excludedNodes,
+  protected DatanodeDescriptor chooseRandom(int numOfReplicas,
+                            String scope,
+                            Map<Node, Node> excludedNodes,
                             long blocksize,
                             int maxNodesPerRack,
                             List<DatanodeDescriptor> results,
                             boolean avoidStaleNodes)
-    throws NotEnoughReplicasException {
+                                throws NotEnoughReplicasException {
       
-    int numOfAvailableNodes =
-      clusterMap.countNumOfAvailableNodes(nodes, excludedNodes.keySet());
+    int numOfAvailableNodes = clusterMap.countNumOfAvailableNodes(
+        scope, excludedNodes.keySet());
     StringBuilder builder = null;
     if (LOG.isDebugEnabled()) {
-      builder = threadLocalBuilder.get();
+      builder = debugLoggingBuilder.get();
       builder.setLength(0);
       builder.append("[");
     }
     boolean badTarget = false;
+    DatanodeDescriptor firstChosen = null;
     while(numOfReplicas > 0 && numOfAvailableNodes > 0) {
       DatanodeDescriptor chosenNode = 
-        (DatanodeDescriptor)(clusterMap.chooseRandom(nodes));
+          (DatanodeDescriptor)clusterMap.chooseRandom(scope);
       Node oldNode = excludedNodes.put(chosenNode, chosenNode);
       if (oldNode == null) {
         numOfAvailableNodes--;
 
-        if (isGoodTarget(chosenNode, blocksize, 
-              maxNodesPerRack, results, avoidStaleNodes)) {
+        int newExcludedNodes = addIfIsGoodTarget(chosenNode, excludedNodes,
+            blocksize, maxNodesPerRack, considerLoad, results, avoidStaleNodes);
+        if (newExcludedNodes >= 0) {
           numOfReplicas--;
-          results.add(chosenNode);
-          // add chosenNode and related nodes to excludedNode
-          int newExcludedNodes = addToExcludedNodes(chosenNode, excludedNodes);
+          if (firstChosen == null) {
+            firstChosen = chosenNode;
+          }
           numOfAvailableNodes -= newExcludedNodes;
-          adjustExcludedNodes(excludedNodes, chosenNode);
         } else {
           badTarget = true;
         }
@@ -544,34 +500,44 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
       }
       throw new NotEnoughReplicasException(detail);
     }
+    
+    return firstChosen;
   }
-  
+
   /**
-   * After choosing a node to place replica, adjust excluded nodes accordingly.
-   * It should do nothing here as chosenNode is already put into exlcudeNodes, 
-   * but it can be overridden in subclass to put more related nodes into 
-   * excludedNodes.
-   * 
-   * @param excludedNodes
-   * @param chosenNode
+   * If the given node is a good target, add it to the result list and
+   * update the excluded node map.
+   * @return -1 if the given is not a good target;
+   *         otherwise, return the number of excluded nodes added to the map.
    */
-  protected void adjustExcludedNodes(HashMap<Node, Node> excludedNodes,
-      Node chosenNode) {
-    // do nothing here.
+  int addIfIsGoodTarget(DatanodeDescriptor node,
+      Map<Node, Node> excludedNodes,
+      long blockSize,
+      int maxNodesPerRack,
+      boolean considerLoad,
+      List<DatanodeDescriptor> results,                           
+      boolean avoidStaleNodes) {
+    if (isGoodTarget(node, blockSize, maxNodesPerRack, considerLoad,
+        results, avoidStaleNodes)) {
+      results.add(node);
+      // add node and related nodes to excludedNode
+      return addToExcludedNodes(node, excludedNodes);
+    } else { 
+      return -1;
+    }
   }
 
-  /* judge if a node is a good target.
-   * return true if <i>node</i> has enough space, 
-   * does not have too much load, and the rack does not have too many nodes
-   */
-  private boolean isGoodTarget(DatanodeDescriptor node,
-                               long blockSize, int maxTargetPerRack,
-                               List<DatanodeDescriptor> results, 
-                               boolean avoidStaleNodes) {
-    return isGoodTarget(node, blockSize, maxTargetPerRack, this.considerLoad,
-        results, avoidStaleNodes);
+  private static void logNodeIsNotChosen(DatanodeDescriptor node, String reason) {
+    if (LOG.isDebugEnabled()) {
+      // build the error message for later use.
+      debugLoggingBuilder.get()
+          .append(node).append(": ")
+          .append("Node ").append(NodeBase.getPath(node))
+          .append(" is not chosen because ")
+          .append(reason);
+    }
   }
-  
+
   /**
    * Determine if a node is a good target. 
    * 
@@ -588,28 +554,20 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
    *         does not have too much load, 
    *         and the rack does not have too many nodes.
    */
-  protected boolean isGoodTarget(DatanodeDescriptor node,
+  private boolean isGoodTarget(DatanodeDescriptor node,
                                long blockSize, int maxTargetPerRack,
                                boolean considerLoad,
                                List<DatanodeDescriptor> results,                           
                                boolean avoidStaleNodes) {
     // check if the node is (being) decommissed
     if (node.isDecommissionInProgress() || node.isDecommissioned()) {
-      if(LOG.isDebugEnabled()) {
-        threadLocalBuilder.get().append(node.toString()).append(": ")
-          .append("Node ").append(NodeBase.getPath(node))
-          .append(" is not chosen because the node is (being) decommissioned ");
-      }
+      logNodeIsNotChosen(node, "the node is (being) decommissioned ");
       return false;
     }
 
     if (avoidStaleNodes) {
       if (node.isStale(this.staleInterval)) {
-        if (LOG.isDebugEnabled()) {
-          threadLocalBuilder.get().append(node.toString()).append(": ")
-              .append("Node ").append(NodeBase.getPath(node))
-              .append(" is not chosen because the node is stale ");
-        }
+        logNodeIsNotChosen(node, "the node is stale ");
         return false;
       }
     }
@@ -618,11 +576,7 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
                      (node.getBlocksScheduled() * blockSize); 
     // check the remaining capacity of the target machine
     if (blockSize* HdfsConstants.MIN_BLOCKS_FOR_WRITE>remaining) {
-      if(LOG.isDebugEnabled()) {
-        threadLocalBuilder.get().append(node.toString()).append(": ")
-          .append("Node ").append(NodeBase.getPath(node))
-          .append(" is not chosen because the node does not have enough space ");
-      }
+      logNodeIsNotChosen(node, "the node does not have enough space ");
       return false;
     }
       
@@ -634,11 +588,7 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
         avgLoad = (double)stats.getTotalLoad()/size;
       }
       if (node.getXceiverCount() > (2.0 * avgLoad)) {
-        if(LOG.isDebugEnabled()) {
-          threadLocalBuilder.get().append(node.toString()).append(": ")
-            .append("Node ").append(NodeBase.getPath(node))
-            .append(" is not chosen because the node is too busy ");
-        }
+        logNodeIsNotChosen(node, "the node is too busy ");
         return false;
       }
     }
@@ -646,31 +596,25 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
     // check if the target rack has chosen too many nodes
     String rackname = node.getNetworkLocation();
     int counter=1;
-    for(Iterator<DatanodeDescriptor> iter = results.iterator();
-        iter.hasNext();) {
-      Node result = iter.next();
+    for(Node result : results) {
       if (rackname.equals(result.getNetworkLocation())) {
         counter++;
       }
     }
     if (counter>maxTargetPerRack) {
-      if(LOG.isDebugEnabled()) {
-        threadLocalBuilder.get().append(node.toString()).append(": ")
-          .append("Node ").append(NodeBase.getPath(node))
-          .append(" is not chosen because the rack has too many chosen nodes ");
-      }
+      logNodeIsNotChosen(node, "the rack has too many chosen nodes ");
       return false;
     }
     return true;
   }
     
-  /* Return a pipeline of nodes.
+  /**
+   * Return a pipeline of nodes.
    * The pipeline is formed finding a shortest path that 
    * starts from the writer and traverses all <i>nodes</i>
    * This is basically a traveling salesman problem.
    */
-  private DatanodeDescriptor[] getPipeline(
-                                           DatanodeDescriptor writer,
+  private DatanodeDescriptor[] getPipeline(DatanodeDescriptor writer,
                                            DatanodeDescriptor[] nodes) {
     if (nodes.length==0) return nodes;
       
@@ -709,7 +653,7 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
                                   int minRacks) {
     DatanodeInfo[] locs = lBlk.getLocations();
     if (locs == null)
-      locs = new DatanodeInfo[0];
+      locs = DatanodeDescriptor.EMPTY_ARRAY;
     int numRacks = clusterMap.getNumOfRacks();
     if(numRacks <= 1) // only one rack
       return 0;
@@ -724,24 +668,18 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
 
   @Override
   public DatanodeDescriptor chooseReplicaToDelete(BlockCollection bc,
-                                                 Block block,
-                                                 short replicationFactor,
-                                                 Collection<DatanodeDescriptor> first, 
-                                                 Collection<DatanodeDescriptor> second) {
+      Block block, short replicationFactor,
+      Collection<DatanodeDescriptor> first,
+      Collection<DatanodeDescriptor> second) {
     long oldestHeartbeat =
       now() - heartbeatInterval * tolerateHeartbeatMultiplier;
     DatanodeDescriptor oldestHeartbeatNode = null;
     long minSpace = Long.MAX_VALUE;
     DatanodeDescriptor minSpaceNode = null;
 
-    // pick replica from the first Set. If first is empty, then pick replicas
-    // from second set.
-    Iterator<DatanodeDescriptor> iter = pickupReplicaSet(first, second);
-
     // Pick the node with the oldest heartbeat or with the least free space,
     // if all hearbeats are within the tolerable heartbeat interval
-    while (iter.hasNext() ) {
-      DatanodeDescriptor node = iter.next();
+    for(DatanodeDescriptor node : pickupReplicaSet(first, second)) {
       long free = node.getRemaining();
       long lastHeartbeat = node.getLastUpdate();
       if(lastHeartbeat < oldestHeartbeat) {
@@ -762,12 +700,10 @@ public class BlockPlacementPolicyDefault extends BlockPlacementPolicy {
    * replica while second set contains remaining replica nodes.
    * So pick up first set if not empty. If first is empty, then pick second.
    */
-  protected Iterator<DatanodeDescriptor> pickupReplicaSet(
+  protected Collection<DatanodeDescriptor> pickupReplicaSet(
       Collection<DatanodeDescriptor> first,
       Collection<DatanodeDescriptor> second) {
-    Iterator<DatanodeDescriptor> iter =
-        first.isEmpty() ? second.iterator() : first.iterator();
-    return iter;
+    return first.isEmpty() ? second : first;
   }
   
   @VisibleForTesting

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockPlacementPolicyWithNodeGroup.java

@@ -20,7 +20,6 @@ package org.apache.hadoop.hdfs.server.blockmanagement;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashMap;
-import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 
@@ -65,7 +64,7 @@ public class BlockPlacementPolicyWithNodeGroup extends BlockPlacementPolicyDefau
    */
   @Override
   protected DatanodeDescriptor chooseLocalNode(DatanodeDescriptor localMachine,
-      HashMap<Node, Node> excludedNodes, long blocksize, int maxNodesPerRack,
+      Map<Node, Node> excludedNodes, long blocksize, int maxNodesPerRack,
       List<DatanodeDescriptor> results, boolean avoidStaleNodes)
         throws NotEnoughReplicasException {
     // if no local machine, randomly choose one node
@@ -76,12 +75,8 @@ public class BlockPlacementPolicyWithNodeGroup extends BlockPlacementPolicyDefau
     // otherwise try local machine first
     Node oldNode = excludedNodes.put(localMachine, localMachine);
     if (oldNode == null) { // was not in the excluded list
-      if (isGoodTarget(localMachine, blocksize,
-          maxNodesPerRack, false, results, avoidStaleNodes)) {
-        results.add(localMachine);
-        // Nodes under same nodegroup should be excluded.
-        addNodeGroupToExcludedNodes(excludedNodes,
-            localMachine.getNetworkLocation());
+      if (addIfIsGoodTarget(localMachine, excludedNodes, blocksize,
+          maxNodesPerRack, false, results, avoidStaleNodes) >= 0) {
         return localMachine;
       }
     } 
@@ -98,26 +93,10 @@ public class BlockPlacementPolicyWithNodeGroup extends BlockPlacementPolicyDefau
         blocksize, maxNodesPerRack, results, avoidStaleNodes);
   }
 
-  @Override
-  protected void adjustExcludedNodes(HashMap<Node, Node> excludedNodes,
-      Node chosenNode) {
-    // as node-group aware implementation, it should make sure no two replica
-    // are placing on the same node group.
-    addNodeGroupToExcludedNodes(excludedNodes, chosenNode.getNetworkLocation());
-  }
   
-  // add all nodes under specific nodegroup to excludedNodes.
-  private void addNodeGroupToExcludedNodes(HashMap<Node, Node> excludedNodes,
-      String nodeGroup) {
-    List<Node> leafNodes = clusterMap.getLeaves(nodeGroup);
-    for (Node node : leafNodes) {
-      excludedNodes.put(node, node);
-    }
-  }
-
   @Override
   protected DatanodeDescriptor chooseLocalRack(DatanodeDescriptor localMachine,
-      HashMap<Node, Node> excludedNodes, long blocksize, int maxNodesPerRack,
+      Map<Node, Node> excludedNodes, long blocksize, int maxNodesPerRack,
       List<DatanodeDescriptor> results, boolean avoidStaleNodes)
       throws NotEnoughReplicasException {
     // no local machine, so choose a random machine
@@ -137,9 +116,7 @@ public class BlockPlacementPolicyWithNodeGroup extends BlockPlacementPolicyDefau
     } catch (NotEnoughReplicasException e1) {
       // find the second replica
       DatanodeDescriptor newLocal=null;
-      for(Iterator<DatanodeDescriptor> iter=results.iterator();
-          iter.hasNext();) {
-        DatanodeDescriptor nextNode = iter.next();
+      for(DatanodeDescriptor nextNode : results) {
         if (nextNode != localMachine) {
           newLocal = nextNode;
           break;
@@ -165,7 +142,7 @@ public class BlockPlacementPolicyWithNodeGroup extends BlockPlacementPolicyDefau
 
   @Override
   protected void chooseRemoteRack(int numOfReplicas,
-      DatanodeDescriptor localMachine, HashMap<Node, Node> excludedNodes,
+      DatanodeDescriptor localMachine, Map<Node, Node> excludedNodes,
       long blocksize, int maxReplicasPerRack, List<DatanodeDescriptor> results,
       boolean avoidStaleNodes) throws NotEnoughReplicasException {
     int oldNumOfReplicas = results.size();
@@ -192,7 +169,7 @@ public class BlockPlacementPolicyWithNodeGroup extends BlockPlacementPolicyDefau
    */
   private DatanodeDescriptor chooseLocalNodeGroup(
       NetworkTopologyWithNodeGroup clusterMap, DatanodeDescriptor localMachine,
-      HashMap<Node, Node> excludedNodes, long blocksize, int maxNodesPerRack,
+      Map<Node, Node> excludedNodes, long blocksize, int maxNodesPerRack,
       List<DatanodeDescriptor> results, boolean avoidStaleNodes)
       throws NotEnoughReplicasException {
     // no local machine, so choose a random machine
@@ -209,9 +186,7 @@ public class BlockPlacementPolicyWithNodeGroup extends BlockPlacementPolicyDefau
     } catch (NotEnoughReplicasException e1) {
       // find the second replica
       DatanodeDescriptor newLocal=null;
-      for(Iterator<DatanodeDescriptor> iter=results.iterator();
-        iter.hasNext();) {
-        DatanodeDescriptor nextNode = iter.next();
+      for(DatanodeDescriptor nextNode : results) {
         if (nextNode != localMachine) {
           newLocal = nextNode;
           break;
@@ -248,10 +223,11 @@ public class BlockPlacementPolicyWithNodeGroup extends BlockPlacementPolicyDefau
    * within the same nodegroup
    * @return number of new excluded nodes
    */
-  protected int addToExcludedNodes(DatanodeDescriptor localMachine,
-      HashMap<Node, Node> excludedNodes) {
+  @Override
+  protected int addToExcludedNodes(DatanodeDescriptor chosenNode,
+      Map<Node, Node> excludedNodes) {
     int countOfExcludedNodes = 0;
-    String nodeGroupScope = localMachine.getNetworkLocation();
+    String nodeGroupScope = chosenNode.getNetworkLocation();
     List<Node> leafNodes = clusterMap.getLeaves(nodeGroupScope);
     for (Node leafNode : leafNodes) {
       Node node = excludedNodes.put(leafNode, leafNode);
@@ -274,12 +250,12 @@ public class BlockPlacementPolicyWithNodeGroup extends BlockPlacementPolicyDefau
    * If first is empty, then pick second.
    */
   @Override
-  public Iterator<DatanodeDescriptor> pickupReplicaSet(
+  public Collection<DatanodeDescriptor> pickupReplicaSet(
       Collection<DatanodeDescriptor> first,
       Collection<DatanodeDescriptor> second) {
     // If no replica within same rack, return directly.
     if (first.isEmpty()) {
-      return second.iterator();
+      return second;
     }
     // Split data nodes in the first set into two sets, 
     // moreThanOne contains nodes on nodegroup with more than one replica
@@ -312,9 +288,7 @@ public class BlockPlacementPolicyWithNodeGroup extends BlockPlacementPolicyDefau
       }
     }
     
-    Iterator<DatanodeDescriptor> iter =
-        moreThanOne.isEmpty() ? exactlyOne.iterator() : moreThanOne.iterator();
-    return iter;
+    return moreThanOne.isEmpty()? exactlyOne : moreThanOne;
   }
   
 }

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/DatanodeDescriptor.java

@@ -38,7 +38,8 @@ import org.apache.hadoop.util.Time;
 @InterfaceAudience.Private
 @InterfaceStability.Evolving
 public class DatanodeDescriptor extends DatanodeInfo {
-  
+  public static final DatanodeDescriptor[] EMPTY_ARRAY = {};
+
   // Stores status of decommissioning.
   // If node is not decommissioning, do not use this object for anything.
   public DecommissioningStatus decommissioningStatus = new DecommissioningStatus();

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/balancer/TestBalancerWithNodeGroup.java

@@ -31,6 +31,7 @@ import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.CommonConfigurationKeysPublic;
 import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.hdfs.DFSConfigKeys;
 import org.apache.hadoop.hdfs.DFSUtil;
 import org.apache.hadoop.hdfs.HdfsConfiguration;
 import org.apache.hadoop.hdfs.MiniDFSCluster;
@@ -39,9 +40,11 @@ import org.apache.hadoop.hdfs.NameNodeProxies;
 import org.apache.hadoop.hdfs.protocol.ClientProtocol;
 import org.apache.hadoop.hdfs.protocol.DatanodeInfo;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants.DatanodeReportType;
+import org.apache.hadoop.hdfs.server.blockmanagement.BlockPlacementPolicyWithNodeGroup;
 import org.apache.hadoop.net.NetworkTopology;
+import org.apache.hadoop.net.NetworkTopologyWithNodeGroup;
+import org.junit.Assert;
 import org.junit.Test;
-import junit.framework.Assert;
 
 /**
  * This class tests if a balancer schedules tasks correctly.
@@ -75,10 +78,9 @@ public class TestBalancerWithNodeGroup {
     Configuration conf = new HdfsConfiguration();
     TestBalancer.initConf(conf);
     conf.set(CommonConfigurationKeysPublic.NET_TOPOLOGY_IMPL_KEY, 
-        "org.apache.hadoop.net.NetworkTopologyWithNodeGroup");
-    conf.set("dfs.block.replicator.classname", 
-        "org.apache.hadoop.hdfs.server.blockmanagement." +
-        "BlockPlacementPolicyWithNodeGroup");
+        NetworkTopologyWithNodeGroup.class.getName());
+    conf.set(DFSConfigKeys.DFS_BLOCK_REPLICATOR_CLASSNAME_KEY, 
+        BlockPlacementPolicyWithNodeGroup.class.getName());
     return conf;
   }
 

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/blockmanagement/TestRBWBlockInvalidation.java

@@ -157,8 +157,8 @@ public class TestRBWBlockInvalidation {
     // in the context of the test, whereas a random one is more accurate
     // to what is seen in real clusters (nodes have random amounts of free
     // space)
-    conf.setClass("dfs.block.replicator.classname", RandomDeleterPolicy.class,
-        BlockPlacementPolicy.class); 
+    conf.setClass(DFSConfigKeys.DFS_BLOCK_REPLICATOR_CLASSNAME_KEY,
+        RandomDeleterPolicy.class, BlockPlacementPolicy.class); 
 
     // Speed up the test a bit with faster heartbeats.
     conf.setInt(DFSConfigKeys.DFS_HEARTBEAT_INTERVAL_KEY, 1);

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/blockmanagement/TestReplicationPolicy.java

@@ -136,30 +136,25 @@ public class TestReplicationPolicy {
         HdfsConstants.MIN_BLOCKS_FOR_WRITE*BLOCK_SIZE, 0L, 4, 0); // overloaded
 
     DatanodeDescriptor[] targets;
-    targets = replicator.chooseTarget(filename, 0, dataNodes[0],
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(0);
     assertEquals(targets.length, 0);
     
-    targets = replicator.chooseTarget(filename, 1, dataNodes[0],
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(1);
     assertEquals(targets.length, 1);
     assertEquals(targets[0], dataNodes[0]);
     
-    targets = replicator.chooseTarget(filename,
-                                      2, dataNodes[0], new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(2);
     assertEquals(targets.length, 2);
     assertEquals(targets[0], dataNodes[0]);
     assertFalse(cluster.isOnSameRack(targets[0], targets[1]));
     
-    targets = replicator.chooseTarget(filename, 3, dataNodes[0],
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(3);
     assertEquals(targets.length, 3);
     assertEquals(targets[0], dataNodes[0]);
     assertFalse(cluster.isOnSameRack(targets[0], targets[1]));
     assertTrue(cluster.isOnSameRack(targets[1], targets[2]));
 
-    targets = replicator.chooseTarget(filename, 4, dataNodes[0],
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(4);
     assertEquals(targets.length, 4);
     assertEquals(targets[0], dataNodes[0]);
     assertTrue(cluster.isOnSameRack(targets[1], targets[2]) ||
@@ -171,15 +166,38 @@ public class TestReplicationPolicy {
         HdfsConstants.MIN_BLOCKS_FOR_WRITE*BLOCK_SIZE, 0L, 0, 0); 
   }
 
+  private static DatanodeDescriptor[] chooseTarget(int numOfReplicas) {
+    return chooseTarget(numOfReplicas, dataNodes[0]);
+  }
+
+  private static DatanodeDescriptor[] chooseTarget(int numOfReplicas,
+      DatanodeDescriptor writer) {
+    return chooseTarget(numOfReplicas, writer,
+        new ArrayList<DatanodeDescriptor>());
+  }
+
+  private static DatanodeDescriptor[] chooseTarget(int numOfReplicas,
+      List<DatanodeDescriptor> chosenNodes) {
+    return chooseTarget(numOfReplicas, dataNodes[0], chosenNodes);
+  }
+
+  private static DatanodeDescriptor[] chooseTarget(int numOfReplicas,
+      DatanodeDescriptor writer, List<DatanodeDescriptor> chosenNodes) {
+    return chooseTarget(numOfReplicas, writer, chosenNodes, null);
+  }
+
+  private static DatanodeDescriptor[] chooseTarget(int numOfReplicas,
+      List<DatanodeDescriptor> chosenNodes, Map<Node, Node> excludedNodes) {
+    return chooseTarget(numOfReplicas, dataNodes[0], chosenNodes, excludedNodes);
+  }
+
   private static DatanodeDescriptor[] chooseTarget(
-      BlockPlacementPolicyDefault policy,
       int numOfReplicas,
       DatanodeDescriptor writer,
       List<DatanodeDescriptor> chosenNodes,
-      HashMap<Node, Node> excludedNodes,
-      long blocksize) {
-    return policy.chooseTarget(numOfReplicas, writer, chosenNodes, false,
-        excludedNodes, blocksize);
+      Map<Node, Node> excludedNodes) {
+    return replicator.chooseTarget(filename, numOfReplicas, writer, chosenNodes,
+        false, excludedNodes, BLOCK_SIZE);
   }
 
   /**
@@ -194,28 +212,24 @@ public class TestReplicationPolicy {
   public void testChooseTarget2() throws Exception { 
     HashMap<Node, Node> excludedNodes;
     DatanodeDescriptor[] targets;
-    BlockPlacementPolicyDefault repl = (BlockPlacementPolicyDefault)replicator;
     List<DatanodeDescriptor> chosenNodes = new ArrayList<DatanodeDescriptor>();
     
     excludedNodes = new HashMap<Node, Node>();
     excludedNodes.put(dataNodes[1], dataNodes[1]); 
-    targets = chooseTarget(repl, 0, dataNodes[0], chosenNodes, excludedNodes,
-        BLOCK_SIZE);
+    targets = chooseTarget(0, chosenNodes, excludedNodes);
     assertEquals(targets.length, 0);
     
     excludedNodes.clear();
     chosenNodes.clear();
     excludedNodes.put(dataNodes[1], dataNodes[1]); 
-    targets = chooseTarget(repl, 1, dataNodes[0], chosenNodes, excludedNodes,
-        BLOCK_SIZE);
+    targets = chooseTarget(1, chosenNodes, excludedNodes);
     assertEquals(targets.length, 1);
     assertEquals(targets[0], dataNodes[0]);
     
     excludedNodes.clear();
     chosenNodes.clear();
     excludedNodes.put(dataNodes[1], dataNodes[1]); 
-    targets = chooseTarget(repl, 2, dataNodes[0], chosenNodes, excludedNodes,
-        BLOCK_SIZE);
+    targets = chooseTarget(2, chosenNodes, excludedNodes);
     assertEquals(targets.length, 2);
     assertEquals(targets[0], dataNodes[0]);
     assertFalse(cluster.isOnSameRack(targets[0], targets[1]));
@@ -223,8 +237,7 @@ public class TestReplicationPolicy {
     excludedNodes.clear();
     chosenNodes.clear();
     excludedNodes.put(dataNodes[1], dataNodes[1]); 
-    targets = chooseTarget(repl, 3, dataNodes[0], chosenNodes, excludedNodes,
-        BLOCK_SIZE);
+    targets = chooseTarget(3, chosenNodes, excludedNodes);
     assertEquals(targets.length, 3);
     assertEquals(targets[0], dataNodes[0]);
     assertFalse(cluster.isOnSameRack(targets[0], targets[1]));
@@ -233,8 +246,7 @@ public class TestReplicationPolicy {
     excludedNodes.clear();
     chosenNodes.clear();
     excludedNodes.put(dataNodes[1], dataNodes[1]); 
-    targets = chooseTarget(repl, 4, dataNodes[0], chosenNodes, excludedNodes,
-        BLOCK_SIZE);
+    targets = chooseTarget(4, chosenNodes, excludedNodes);
     assertEquals(targets.length, 4);
     assertEquals(targets[0], dataNodes[0]);
     for(int i=1; i<4; i++) {
@@ -248,7 +260,7 @@ public class TestReplicationPolicy {
     chosenNodes.clear();
     excludedNodes.put(dataNodes[1], dataNodes[1]); 
     chosenNodes.add(dataNodes[2]);
-    targets = repl.chooseTarget(1, dataNodes[0], chosenNodes, true,
+    targets = replicator.chooseTarget(filename, 1, dataNodes[0], chosenNodes, true,
         excludedNodes, BLOCK_SIZE);
     System.out.println("targets=" + Arrays.asList(targets));
     assertEquals(2, targets.length);
@@ -274,30 +286,25 @@ public class TestReplicationPolicy {
         (HdfsConstants.MIN_BLOCKS_FOR_WRITE-1)*BLOCK_SIZE, 0L, 0, 0); // no space
         
     DatanodeDescriptor[] targets;
-    targets = replicator.chooseTarget(filename, 0, dataNodes[0],
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(0);
     assertEquals(targets.length, 0);
     
-    targets = replicator.chooseTarget(filename, 1, dataNodes[0],
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(1);
     assertEquals(targets.length, 1);
     assertEquals(targets[0], dataNodes[1]);
     
-    targets = replicator.chooseTarget(filename, 2, dataNodes[0],
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(2);
     assertEquals(targets.length, 2);
     assertEquals(targets[0], dataNodes[1]);
     assertFalse(cluster.isOnSameRack(targets[0], targets[1]));
     
-    targets = replicator.chooseTarget(filename, 3, dataNodes[0],
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(3);
     assertEquals(targets.length, 3);
     assertEquals(targets[0], dataNodes[1]);
     assertTrue(cluster.isOnSameRack(targets[1], targets[2]));
     assertFalse(cluster.isOnSameRack(targets[0], targets[1]));
     
-    targets = replicator.chooseTarget(filename, 4, dataNodes[0],
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(4);
     assertEquals(targets.length, 4);
     assertEquals(targets[0], dataNodes[1]);
     for(int i=1; i<4; i++) {
@@ -330,23 +337,19 @@ public class TestReplicationPolicy {
     }
       
     DatanodeDescriptor[] targets;
-    targets = replicator.chooseTarget(filename, 0, dataNodes[0],
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(0);
     assertEquals(targets.length, 0);
     
-    targets = replicator.chooseTarget(filename, 1, dataNodes[0],
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(1);
     assertEquals(targets.length, 1);
     assertFalse(cluster.isOnSameRack(targets[0], dataNodes[0]));
     
-    targets = replicator.chooseTarget(filename, 2, dataNodes[0],
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(2);
     assertEquals(targets.length, 2);
     assertFalse(cluster.isOnSameRack(targets[0], dataNodes[0]));
     assertFalse(cluster.isOnSameRack(targets[0], targets[1]));
     
-    targets = replicator.chooseTarget(filename, 3, dataNodes[0],
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(3);
     assertEquals(targets.length, 3);
     for(int i=0; i<3; i++) {
       assertFalse(cluster.isOnSameRack(targets[i], dataNodes[0]));
@@ -375,21 +378,17 @@ public class TestReplicationPolicy {
       DFSTestUtil.getDatanodeDescriptor("7.7.7.7", "/d2/r4");
 
     DatanodeDescriptor[] targets;
-    targets = replicator.chooseTarget(filename, 0, writerDesc,
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(0, writerDesc);
     assertEquals(targets.length, 0);
 
-    targets = replicator.chooseTarget(filename, 1, writerDesc,
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(1, writerDesc);
     assertEquals(targets.length, 1);
 
-    targets = replicator.chooseTarget(filename, 2, writerDesc,
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(2, writerDesc);
     assertEquals(targets.length, 2);
     assertFalse(cluster.isOnSameRack(targets[0], targets[1]));
 
-    targets = replicator.chooseTarget(filename, 3, writerDesc,
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(3, writerDesc);
     assertEquals(targets.length, 3);
     assertTrue(cluster.isOnSameRack(targets[1], targets[2]));
     assertFalse(cluster.isOnSameRack(targets[0], targets[1]));
@@ -433,9 +432,7 @@ public class TestReplicationPolicy {
     
     // try to choose NUM_OF_DATANODES which is more than actually available
     // nodes.
-    DatanodeDescriptor[] targets = replicator.chooseTarget(filename, 
-        NUM_OF_DATANODES, dataNodes[0], new ArrayList<DatanodeDescriptor>(),
-        BLOCK_SIZE);
+    DatanodeDescriptor[] targets = chooseTarget(NUM_OF_DATANODES);
     assertEquals(targets.length, NUM_OF_DATANODES - 2);
 
     final List<LoggingEvent> log = appender.getLog();
@@ -478,17 +475,14 @@ public class TestReplicationPolicy {
     DatanodeDescriptor[] targets;
     // We set the datanode[0] as stale, thus should choose datanode[1] since
     // datanode[1] is on the same rack with datanode[0] (writer)
-    targets = replicator.chooseTarget(filename, 1, dataNodes[0],
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(1);
     assertEquals(targets.length, 1);
     assertEquals(targets[0], dataNodes[1]);
 
     HashMap<Node, Node> excludedNodes = new HashMap<Node, Node>();
     excludedNodes.put(dataNodes[1], dataNodes[1]);
     List<DatanodeDescriptor> chosenNodes = new ArrayList<DatanodeDescriptor>();
-    BlockPlacementPolicyDefault repl = (BlockPlacementPolicyDefault)replicator;
-    targets = chooseTarget(repl, 1, dataNodes[0], chosenNodes, excludedNodes,
-        BLOCK_SIZE);
+    targets = chooseTarget(1, chosenNodes, excludedNodes);
     assertEquals(targets.length, 1);
     assertFalse(cluster.isOnSameRack(targets[0], dataNodes[0]));
     
@@ -515,33 +509,27 @@ public class TestReplicationPolicy {
     namenode.getNamesystem().getBlockManager()
       .getDatanodeManager().getHeartbeatManager().heartbeatCheck();
 
-    DatanodeDescriptor[] targets;
-    targets = replicator.chooseTarget(filename, 0, dataNodes[0],
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    DatanodeDescriptor[] targets = chooseTarget(0);
     assertEquals(targets.length, 0);
 
     // Since we have 6 datanodes total, stale nodes should
     // not be returned until we ask for more than 3 targets
-    targets = replicator.chooseTarget(filename, 1, dataNodes[0],
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(1);
     assertEquals(targets.length, 1);
     assertFalse(containsWithinRange(targets[0], dataNodes, 0, 2));
 
-    targets = replicator.chooseTarget(filename, 2, dataNodes[0],
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(2);
     assertEquals(targets.length, 2);
     assertFalse(containsWithinRange(targets[0], dataNodes, 0, 2));
     assertFalse(containsWithinRange(targets[1], dataNodes, 0, 2));
 
-    targets = replicator.chooseTarget(filename, 3, dataNodes[0],
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(3);
     assertEquals(targets.length, 3);
     assertTrue(containsWithinRange(targets[0], dataNodes, 3, 5));
     assertTrue(containsWithinRange(targets[1], dataNodes, 3, 5));
     assertTrue(containsWithinRange(targets[2], dataNodes, 3, 5));
 
-    targets = replicator.chooseTarget(filename, 4, dataNodes[0],
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(4);
     assertEquals(targets.length, 4);
     assertTrue(containsWithinRange(dataNodes[3], targets, 0, 3));
     assertTrue(containsWithinRange(dataNodes[4], targets, 0, 3));
@@ -594,7 +582,8 @@ public class TestReplicationPolicy {
       BlockPlacementPolicy replicator = miniCluster.getNameNode()
           .getNamesystem().getBlockManager().getBlockPlacementPolicy();
       DatanodeDescriptor[] targets = replicator.chooseTarget(filename, 3,
-          staleNodeInfo, new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+          staleNodeInfo, new ArrayList<DatanodeDescriptor>(), false, null, BLOCK_SIZE);
+
       assertEquals(targets.length, 3);
       assertFalse(cluster.isOnSameRack(targets[0], staleNodeInfo));
       
@@ -618,7 +607,7 @@ public class TestReplicationPolicy {
           .getDatanodeManager().shouldAvoidStaleDataNodesForWrite());
       // Call chooseTarget
       targets = replicator.chooseTarget(filename, 3,
-          staleNodeInfo, new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+          staleNodeInfo, new ArrayList<DatanodeDescriptor>(), false, null, BLOCK_SIZE);
       assertEquals(targets.length, 3);
       assertTrue(cluster.isOnSameRack(targets[0], staleNodeInfo));
       
@@ -640,8 +629,7 @@ public class TestReplicationPolicy {
       assertTrue(miniCluster.getNameNode().getNamesystem().getBlockManager()
           .getDatanodeManager().shouldAvoidStaleDataNodesForWrite());
       // Call chooseTarget
-      targets = replicator.chooseTarget(filename, 3,
-          staleNodeInfo, new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+      targets = chooseTarget(3, staleNodeInfo);
       assertEquals(targets.length, 3);
       assertFalse(cluster.isOnSameRack(targets[0], staleNodeInfo));
     } finally {
@@ -662,23 +650,19 @@ public class TestReplicationPolicy {
     chosenNodes.add(dataNodes[0]);    
     DatanodeDescriptor[] targets;
     
-    targets = replicator.chooseTarget(filename,
-                                      0, dataNodes[0], chosenNodes, BLOCK_SIZE);
+    targets = chooseTarget(0, chosenNodes);
     assertEquals(targets.length, 0);
     
-    targets = replicator.chooseTarget(filename,
-                                      1, dataNodes[0], chosenNodes, BLOCK_SIZE);
+    targets = chooseTarget(1, chosenNodes);
     assertEquals(targets.length, 1);
     assertFalse(cluster.isOnSameRack(dataNodes[0], targets[0]));
     
-    targets = replicator.chooseTarget(filename,
-                                      2, dataNodes[0], chosenNodes, BLOCK_SIZE);
+    targets = chooseTarget(2, chosenNodes);
     assertEquals(targets.length, 2);
     assertTrue(cluster.isOnSameRack(dataNodes[0], targets[0]));
     assertFalse(cluster.isOnSameRack(targets[0], targets[1]));
     
-    targets = replicator.chooseTarget(filename,
-                                      3, dataNodes[0], chosenNodes, BLOCK_SIZE);
+    targets = chooseTarget(3, chosenNodes);
     assertEquals(targets.length, 3);
     assertTrue(cluster.isOnSameRack(dataNodes[0], targets[0]));
     assertFalse(cluster.isOnSameRack(targets[0], targets[2]));
@@ -698,17 +682,14 @@ public class TestReplicationPolicy {
     chosenNodes.add(dataNodes[1]);
 
     DatanodeDescriptor[] targets;
-    targets = replicator.chooseTarget(filename,
-                                      0, dataNodes[0], chosenNodes, BLOCK_SIZE);
+    targets = chooseTarget(0, chosenNodes);
     assertEquals(targets.length, 0);
     
-    targets = replicator.chooseTarget(filename,
-                                      1, dataNodes[0], chosenNodes, BLOCK_SIZE);
+    targets = chooseTarget(1, chosenNodes);
     assertEquals(targets.length, 1);
     assertFalse(cluster.isOnSameRack(dataNodes[0], targets[0]));
     
-    targets = replicator.chooseTarget(filename,
-                                      2, dataNodes[0], chosenNodes, BLOCK_SIZE);
+    targets = chooseTarget(2, chosenNodes);
     assertEquals(targets.length, 2);
     assertFalse(cluster.isOnSameRack(dataNodes[0], targets[0]));
     assertFalse(cluster.isOnSameRack(dataNodes[0], targets[1]));
@@ -728,29 +709,24 @@ public class TestReplicationPolicy {
     chosenNodes.add(dataNodes[2]);
     
     DatanodeDescriptor[] targets;
-    targets = replicator.chooseTarget(filename,
-                                      0, dataNodes[0], chosenNodes, BLOCK_SIZE);
+    targets = chooseTarget(0, chosenNodes);
     assertEquals(targets.length, 0);
     
-    targets = replicator.chooseTarget(filename,
-                                      1, dataNodes[0], chosenNodes, BLOCK_SIZE);
+    targets = chooseTarget(1, chosenNodes);
     assertEquals(targets.length, 1);
     assertTrue(cluster.isOnSameRack(dataNodes[0], targets[0]));
     assertFalse(cluster.isOnSameRack(dataNodes[2], targets[0]));
     
-    targets = replicator.chooseTarget(filename,
-                               1, dataNodes[2], chosenNodes, BLOCK_SIZE);
+    targets = chooseTarget(1, dataNodes[2], chosenNodes);
     assertEquals(targets.length, 1);
     assertTrue(cluster.isOnSameRack(dataNodes[2], targets[0]));
     assertFalse(cluster.isOnSameRack(dataNodes[0], targets[0]));
 
-    targets = replicator.chooseTarget(filename,
-                                      2, dataNodes[0], chosenNodes, BLOCK_SIZE);
+    targets = chooseTarget(2, chosenNodes);
     assertEquals(targets.length, 2);
     assertTrue(cluster.isOnSameRack(dataNodes[0], targets[0]));
     
-    targets = replicator.chooseTarget(filename,
-                               2, dataNodes[2], chosenNodes, BLOCK_SIZE);
+    targets = chooseTarget(2, dataNodes[2], chosenNodes);
     assertEquals(targets.length, 2);
     assertTrue(cluster.isOnSameRack(dataNodes[2], targets[0]));
   }

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/blockmanagement/TestReplicationPolicyWithNodeGroup.java

@@ -39,6 +39,7 @@ import org.apache.hadoop.hdfs.HdfsConfiguration;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants;
 import org.apache.hadoop.hdfs.server.namenode.NameNode;
 import org.apache.hadoop.net.NetworkTopology;
+import org.apache.hadoop.net.NetworkTopologyWithNodeGroup;
 import org.apache.hadoop.net.Node;
 import org.apache.hadoop.test.PathUtils;
 import org.junit.After;
@@ -101,10 +102,10 @@ public class TestReplicationPolicyWithNodeGroup {
     FileSystem.setDefaultUri(CONF, "hdfs://localhost:0");
     CONF.set(DFSConfigKeys.DFS_NAMENODE_HTTP_ADDRESS_KEY, "0.0.0.0:0");
     // Set properties to make HDFS aware of NodeGroup.
-    CONF.set("dfs.block.replicator.classname", 
-        "org.apache.hadoop.hdfs.server.blockmanagement.BlockPlacementPolicyWithNodeGroup");
+    CONF.set(DFSConfigKeys.DFS_BLOCK_REPLICATOR_CLASSNAME_KEY, 
+        BlockPlacementPolicyWithNodeGroup.class.getName());
     CONF.set(CommonConfigurationKeysPublic.NET_TOPOLOGY_IMPL_KEY, 
-        "org.apache.hadoop.net.NetworkTopologyWithNodeGroup");
+        NetworkTopologyWithNodeGroup.class.getName());
     
     File baseDir = PathUtils.getTestDir(TestReplicationPolicyWithNodeGroup.class);
     
@@ -156,6 +157,35 @@ public class TestReplicationPolicyWithNodeGroup {
     return true;
   }
   
+  private DatanodeDescriptor[] chooseTarget(int numOfReplicas) {
+    return chooseTarget(numOfReplicas, dataNodes[0]);
+  }
+
+  private DatanodeDescriptor[] chooseTarget(int numOfReplicas,
+      DatanodeDescriptor writer) {
+    return chooseTarget(numOfReplicas, writer,
+        new ArrayList<DatanodeDescriptor>());
+  }
+
+  private DatanodeDescriptor[] chooseTarget(int numOfReplicas,
+      List<DatanodeDescriptor> chosenNodes) {
+    return chooseTarget(numOfReplicas, dataNodes[0], chosenNodes);
+  }
+
+  private DatanodeDescriptor[] chooseTarget(int numOfReplicas,
+      DatanodeDescriptor writer, List<DatanodeDescriptor> chosenNodes) {
+    return chooseTarget(numOfReplicas, writer, chosenNodes, null);
+  }
+
+  private DatanodeDescriptor[] chooseTarget(
+      int numOfReplicas,
+      DatanodeDescriptor writer,
+      List<DatanodeDescriptor> chosenNodes,
+      Map<Node, Node> excludedNodes) {
+    return replicator.chooseTarget(filename, numOfReplicas, writer, chosenNodes,
+        false, excludedNodes, BLOCK_SIZE);
+  }
+
   /**
    * In this testcase, client is dataNodes[0]. So the 1st replica should be
    * placed on dataNodes[0], the 2nd replica should be placed on 
@@ -172,31 +202,26 @@ public class TestReplicationPolicyWithNodeGroup {
         HdfsConstants.MIN_BLOCKS_FOR_WRITE*BLOCK_SIZE, 0L, 4, 0); // overloaded
 
     DatanodeDescriptor[] targets;
-    targets = replicator.chooseTarget(filename, 0, dataNodes[0],
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(0);
     assertEquals(targets.length, 0);
 
-    targets = replicator.chooseTarget(filename, 1, dataNodes[0],
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(1);
     assertEquals(targets.length, 1);
     assertEquals(targets[0], dataNodes[0]);
 
-    targets = replicator.chooseTarget(filename, 2, dataNodes[0],
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(2);
     assertEquals(targets.length, 2);
     assertEquals(targets[0], dataNodes[0]);
     assertFalse(cluster.isOnSameRack(targets[0], targets[1]));
 
-    targets = replicator.chooseTarget(filename, 3, dataNodes[0],
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(3);
     assertEquals(targets.length, 3);
     assertEquals(targets[0], dataNodes[0]);
     assertFalse(cluster.isOnSameRack(targets[0], targets[1]));
     assertTrue(cluster.isOnSameRack(targets[1], targets[2]));
     assertFalse(cluster.isOnSameNodeGroup(targets[1], targets[2]));
 
-    targets = replicator.chooseTarget(filename, 4, dataNodes[0],
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(4);
     assertEquals(targets.length, 4);
     assertEquals(targets[0], dataNodes[0]);
     assertTrue(cluster.isOnSameRack(targets[1], targets[2]) ||
@@ -235,7 +260,7 @@ public class TestReplicationPolicyWithNodeGroup {
 
     excludedNodes = new HashMap<Node, Node>();
     excludedNodes.put(dataNodes[1], dataNodes[1]); 
-    targets = repl.chooseTarget(4, dataNodes[0], chosenNodes, false, 
+    targets = repl.chooseTarget(filename, 4, dataNodes[0], chosenNodes, false, 
         excludedNodes, BLOCK_SIZE);
     assertEquals(targets.length, 4);
     assertEquals(targets[0], dataNodes[0]);
@@ -252,7 +277,7 @@ public class TestReplicationPolicyWithNodeGroup {
     chosenNodes.clear();
     excludedNodes.put(dataNodes[1], dataNodes[1]); 
     chosenNodes.add(dataNodes[2]);
-    targets = repl.chooseTarget(1, dataNodes[0], chosenNodes, true,
+    targets = repl.chooseTarget(filename, 1, dataNodes[0], chosenNodes, true,
         excludedNodes, BLOCK_SIZE);
     System.out.println("targets=" + Arrays.asList(targets));
     assertEquals(2, targets.length);
@@ -278,30 +303,25 @@ public class TestReplicationPolicyWithNodeGroup {
         (HdfsConstants.MIN_BLOCKS_FOR_WRITE-1)*BLOCK_SIZE, 0L, 0, 0); // no space
 
     DatanodeDescriptor[] targets;
-    targets = replicator.chooseTarget(filename, 0, dataNodes[0],
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(0);
     assertEquals(targets.length, 0);
 
-    targets = replicator.chooseTarget(filename, 1, dataNodes[0],
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(1);
     assertEquals(targets.length, 1);
     assertEquals(targets[0], dataNodes[1]);
 
-    targets = replicator.chooseTarget(filename, 2, dataNodes[0],
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(2);
     assertEquals(targets.length, 2);
     assertEquals(targets[0], dataNodes[1]);
     assertFalse(cluster.isOnSameRack(targets[0], targets[1]));
 
-    targets = replicator.chooseTarget(filename, 3, dataNodes[0],
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(3);
     assertEquals(targets.length, 3);
     assertEquals(targets[0], dataNodes[1]);
     assertTrue(cluster.isOnSameRack(targets[1], targets[2]));
     assertFalse(cluster.isOnSameRack(targets[0], targets[1]));
 
-    targets = replicator.chooseTarget(filename, 4, dataNodes[0],
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(4);
     assertEquals(targets.length, 4);
     assertEquals(targets[0], dataNodes[1]);
     assertTrue(cluster.isNodeGroupAware());
@@ -333,23 +353,19 @@ public class TestReplicationPolicyWithNodeGroup {
     }
 
     DatanodeDescriptor[] targets;
-    targets = replicator.chooseTarget(filename, 0, dataNodes[0],
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(0);
     assertEquals(targets.length, 0);
 
-    targets = replicator.chooseTarget(filename, 1, dataNodes[0],
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(1);
     assertEquals(targets.length, 1);
     assertFalse(cluster.isOnSameRack(targets[0], dataNodes[0]));
 
-    targets = replicator.chooseTarget(filename, 2, dataNodes[0],
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(2);
     assertEquals(targets.length, 2);
     assertFalse(cluster.isOnSameRack(targets[0], dataNodes[0]));
     assertFalse(cluster.isOnSameRack(targets[0], targets[1]));
 
-    targets = replicator.chooseTarget(filename, 3, dataNodes[0],
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(3);
     assertEquals(targets.length, 3);
     for(int i=0; i<3; i++) {
       assertFalse(cluster.isOnSameRack(targets[i], dataNodes[0]));
@@ -371,21 +387,17 @@ public class TestReplicationPolicyWithNodeGroup {
   public void testChooseTarget5() throws Exception {
     setupDataNodeCapacity();
     DatanodeDescriptor[] targets;
-    targets = replicator.chooseTarget(filename, 0, NODE,
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(0, NODE);
     assertEquals(targets.length, 0);
 
-    targets = replicator.chooseTarget(filename, 1, NODE,
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(1, NODE);
     assertEquals(targets.length, 1);
 
-    targets = replicator.chooseTarget(filename, 2, NODE,
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(2, NODE);
     assertEquals(targets.length, 2);
     assertFalse(cluster.isOnSameRack(targets[0], targets[1]));
 
-    targets = replicator.chooseTarget(filename, 3, NODE,
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(3, NODE);
     assertEquals(targets.length, 3);
     assertTrue(cluster.isOnSameRack(targets[1], targets[2]));
     assertFalse(cluster.isOnSameRack(targets[0], targets[1]));
@@ -406,23 +418,19 @@ public class TestReplicationPolicyWithNodeGroup {
     chosenNodes.add(dataNodes[0]);
     DatanodeDescriptor[] targets;
     
-    targets = replicator.chooseTarget(filename,
-                                      0, dataNodes[0], chosenNodes, BLOCK_SIZE);
+    targets = chooseTarget(0, chosenNodes);
     assertEquals(targets.length, 0);
     
-    targets = replicator.chooseTarget(filename,
-                                      1, dataNodes[0], chosenNodes, BLOCK_SIZE);
+    targets = chooseTarget(1, chosenNodes);
     assertEquals(targets.length, 1);
     assertFalse(cluster.isOnSameRack(dataNodes[0], targets[0]));
     
-    targets = replicator.chooseTarget(filename,
-                                      2, dataNodes[0], chosenNodes, BLOCK_SIZE);
+    targets = chooseTarget(2, chosenNodes);
     assertEquals(targets.length, 2);
     assertTrue(cluster.isOnSameRack(dataNodes[0], targets[0]));
     assertFalse(cluster.isOnSameRack(targets[0], targets[1]));
     
-    targets = replicator.chooseTarget(filename,
-                                      3, dataNodes[0], chosenNodes, BLOCK_SIZE);
+    targets = chooseTarget(3, chosenNodes);
     assertEquals(targets.length, 3);
     assertTrue(cluster.isOnSameRack(dataNodes[0], targets[0]));
     assertFalse(cluster.isOnSameNodeGroup(dataNodes[0], targets[0]));
@@ -444,17 +452,14 @@ public class TestReplicationPolicyWithNodeGroup {
     chosenNodes.add(dataNodes[1]);
 
     DatanodeDescriptor[] targets;
-    targets = replicator.chooseTarget(filename,
-                                      0, dataNodes[0], chosenNodes, BLOCK_SIZE);
+    targets = chooseTarget(0, chosenNodes);
     assertEquals(targets.length, 0);
 
-    targets = replicator.chooseTarget(filename,
-                                      1, dataNodes[0], chosenNodes, BLOCK_SIZE);
+    targets = chooseTarget(1, chosenNodes);
     assertEquals(targets.length, 1);
     assertFalse(cluster.isOnSameRack(dataNodes[0], targets[0]));
 
-    targets = replicator.chooseTarget(filename,
-                                      2, dataNodes[0], chosenNodes, BLOCK_SIZE);
+    targets = chooseTarget(2, chosenNodes);
     assertEquals(targets.length, 2);
     assertFalse(cluster.isOnSameRack(dataNodes[0], targets[0]) && 
         cluster.isOnSameRack(dataNodes[0], targets[1]));
@@ -475,30 +480,26 @@ public class TestReplicationPolicyWithNodeGroup {
     chosenNodes.add(dataNodes[3]);
 
     DatanodeDescriptor[] targets;
-    targets = replicator.chooseTarget(filename,
-                                      0, dataNodes[0], chosenNodes, BLOCK_SIZE);
+    targets = chooseTarget(0, chosenNodes);
     assertEquals(targets.length, 0);
 
-    targets = replicator.chooseTarget(filename,
-                                      1, dataNodes[0], chosenNodes, BLOCK_SIZE);
+    targets = chooseTarget(1, chosenNodes);
     assertEquals(targets.length, 1);
     assertTrue(cluster.isOnSameRack(dataNodes[0], targets[0]));
     assertFalse(cluster.isOnSameRack(dataNodes[3], targets[0]));
 
-    targets = replicator.chooseTarget(filename,
-                               1, dataNodes[3], chosenNodes, BLOCK_SIZE);
+    targets = chooseTarget(1, dataNodes[3], chosenNodes);
     assertEquals(targets.length, 1);
     assertTrue(cluster.isOnSameRack(dataNodes[3], targets[0]));
     assertFalse(cluster.isOnSameNodeGroup(dataNodes[3], targets[0]));
     assertFalse(cluster.isOnSameRack(dataNodes[0], targets[0]));
 
-    targets = replicator.chooseTarget(filename,
-                                      2, dataNodes[0], chosenNodes, BLOCK_SIZE);
+    targets = chooseTarget(2, chosenNodes);
     assertEquals(targets.length, 2);
     assertTrue(cluster.isOnSameRack(dataNodes[0], targets[0]));
     assertFalse(cluster.isOnSameNodeGroup(dataNodes[0], targets[0]));
-    targets = replicator.chooseTarget(filename,
-                               2, dataNodes[3], chosenNodes, BLOCK_SIZE);
+
+    targets = chooseTarget(2, dataNodes[3], chosenNodes);
     assertEquals(targets.length, 2);
     assertTrue(cluster.isOnSameRack(dataNodes[3], targets[0]));
   }
@@ -584,21 +585,17 @@ public class TestReplicationPolicyWithNodeGroup {
     }
 
     DatanodeDescriptor[] targets;
-    targets = replicator.chooseTarget(filename, 0, dataNodesInBoundaryCase[0],
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(0, dataNodesInBoundaryCase[0]);
     assertEquals(targets.length, 0);
     
-    targets = replicator.chooseTarget(filename, 1, dataNodesInBoundaryCase[0],
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(1, dataNodesInBoundaryCase[0]);
     assertEquals(targets.length, 1);
 
-    targets = replicator.chooseTarget(filename, 2, dataNodesInBoundaryCase[0],
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(2, dataNodesInBoundaryCase[0]);
     assertEquals(targets.length, 2);
     assertFalse(cluster.isOnSameRack(targets[0], targets[1]));
     
-    targets = replicator.chooseTarget(filename, 3, dataNodesInBoundaryCase[0],
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(3, dataNodesInBoundaryCase[0]);
     assertEquals(targets.length, 3);
     assertTrue(checkTargetsOnDifferentNodeGroup(targets));
   }
@@ -621,8 +618,7 @@ public class TestReplicationPolicyWithNodeGroup {
     chosenNodes.add(dataNodesInBoundaryCase[0]);
     chosenNodes.add(dataNodesInBoundaryCase[5]);
     DatanodeDescriptor[] targets;
-    targets = replicator.chooseTarget(filename, 1, dataNodesInBoundaryCase[0],
-        chosenNodes, BLOCK_SIZE);
+    targets = chooseTarget(1, dataNodesInBoundaryCase[0], chosenNodes);
     assertFalse(cluster.isOnSameNodeGroup(targets[0], 
         dataNodesInBoundaryCase[0]));
     assertFalse(cluster.isOnSameNodeGroup(targets[0],
@@ -661,14 +657,12 @@ public class TestReplicationPolicyWithNodeGroup {
 
     DatanodeDescriptor[] targets;
     // Test normal case -- 3 replicas
-    targets = replicator.chooseTarget(filename, 3, dataNodesInMoreTargetsCase[0],
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(3, dataNodesInMoreTargetsCase[0]);
     assertEquals(targets.length, 3);
     assertTrue(checkTargetsOnDifferentNodeGroup(targets));
 
     // Test special case -- replica number over node groups.
-    targets = replicator.chooseTarget(filename, 10, dataNodesInMoreTargetsCase[0],
-        new ArrayList<DatanodeDescriptor>(), BLOCK_SIZE);
+    targets = chooseTarget(10, dataNodesInMoreTargetsCase[0]);
     assertTrue(checkTargetsOnDifferentNodeGroup(targets));
     // Verify it only can find 6 targets for placing replicas.
     assertEquals(targets.length, 6);

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/ha/TestDNFencing.java

@@ -96,8 +96,8 @@ public class TestDNFencing {
     // Increase max streams so that we re-replicate quickly.
     conf.setInt(DFSConfigKeys.DFS_NAMENODE_REPLICATION_MAX_STREAMS_KEY, 1000);
     // See RandomDeleterPolicy javadoc.
-    conf.setClass("dfs.block.replicator.classname", RandomDeleterPolicy.class,
-        BlockPlacementPolicy.class); 
+    conf.setClass(DFSConfigKeys.DFS_BLOCK_REPLICATOR_CLASSNAME_KEY,
+        RandomDeleterPolicy.class, BlockPlacementPolicy.class); 
     conf.setInt(DFSConfigKeys.DFS_HA_TAILEDITS_PERIOD_KEY, 1);
     cluster = new MiniDFSCluster.Builder(conf)
       .nnTopology(MiniDFSNNTopology.simpleHATopology())