split pick segment logic into its own method

server/src/main/java/com/metamx/druid/master/BalancerCostAnalyzer.java

@@ -141,7 +141,7 @@ public class BalancerCostAnalyzer
   }
 
   // The balancing application requires us to pick a proposal segment.
-  public BalancerSegmentHolder findNewSegmentHome(List<ServerHolder> serverHolders, int numSegments)
+  public BalancerSegmentHolder pickSegmentToMove(List<ServerHolder> serverHolders, int numSegments)
   {
     // We want to sample from each server w.p. numSegmentsOnServer / totalSegments
     ServerHolder fromServerHolder = sampleServer(serverHolders, numSegments);
@@ -151,9 +151,7 @@ public class BalancerCostAnalyzer
     List<DataSegment> segments = Lists.newArrayList(fromServerHolder.getServer().getSegments().values());
 
     DataSegment proposalSegment = segments.get(rand.nextInt(segments.size()));
-    ServerHolder toServer = findNewSegmentHome(proposalSegment, serverHolders);
+    return new BalancerSegmentHolder(fromServerHolder.getServer(), proposalSegment);
-
-    return new BalancerSegmentHolder(fromServerHolder.getServer(), toServer.getServer(), proposalSegment);
   }
 
   // The assignment application requires us to supply a proposal segment.

server/src/main/java/com/metamx/druid/master/BalancerSegmentHolder.java

@@ -27,19 +27,16 @@ import com.metamx.druid.client.DruidServer;
 public class BalancerSegmentHolder
 {
   private final DruidServer fromServer;
-  private final DruidServer toServer;
   private final DataSegment segment;
 
   private volatile int lifetime = 15;
 
   public BalancerSegmentHolder(
       DruidServer fromServer,
-      DruidServer toServer,
       DataSegment segment
   )
   {
     this.fromServer = fromServer;
-    this.toServer = toServer;
     this.segment = segment;
   }
 
@@ -48,11 +45,6 @@ public class BalancerSegmentHolder
     return fromServer;
   }
 
-  public DruidServer getToServer()
-  {
-    return toServer;
-  }
-
   public DataSegment getSegment()
   {
     return segment;

server/src/main/java/com/metamx/druid/master/DruidMasterBalancer.java

@@ -120,10 +120,11 @@ public class DruidMasterBalancer implements DruidMasterHelper
       int iter = 0;
 
       while (iter < maxSegmentsToMove) {
-        BalancerSegmentHolder holder = analyzer.findNewSegmentHome(serverHolderList, numSegments);
+        BalancerSegmentHolder segmentToMove = analyzer.pickSegmentToMove(serverHolderList, numSegments);
-        if (!segmentsBeingMoved.contains(holder.getSegment())) {
+        DruidServer toServer = analyzer.findNewSegmentHome(segmentToMove.getSegment(), serverHolderList).getServer();
-          moveSegment(holder, params);
+        if (!segmentsBeingMoved.contains(segmentToMove.getSegment())) {
-          segmentsBeingMoved.add(holder.getSegment());
+          moveSegment(segmentToMove, toServer, params);
+          segmentsBeingMoved.add(segmentToMove.getSegment());
         }
         iter++;
       }
@@ -160,14 +161,14 @@ public class DruidMasterBalancer implements DruidMasterHelper
 
   private void moveSegment(
       final BalancerSegmentHolder segment,
+      final DruidServer toServer,
       final DruidMasterRuntimeParams params
   )
   {
-    final DruidServer toServer = segment.getToServer();
+    final String toServerName = toServer.getName();
-    final String toServerName = segment.getToServer().getName();
     final LoadQueuePeon toPeon = params.getLoadManagementPeons().get(toServerName);
 
-    final String fromServer = segment.getFromServer().getName();
+    final String fromServerName = segment.getFromServer().getName();
     final DataSegment segmentToMove = segment.getSegment();
     final String segmentName = segmentToMove.getIdentifier();
 
@@ -177,12 +178,12 @@ public class DruidMasterBalancer implements DruidMasterHelper
       log.info(
           "Moving [%s] from [%s] to [%s]",
           segmentName,
-          fromServer,
+          fromServerName,
           toServerName
       );
       try {
         master.moveSegment(
-            fromServer,
+            fromServerName,
             toServerName,
             segmentToMove.getIdentifier(),
             new LoadPeonCallback()