toppartitions: Fix toppartitions to only jmx once

In line with previous API, nodetool called jmx's toppartitions
for each sampler separately. A better way to do this is to call
it once and then pick results for the samplers we need.

src/java/org/apache/cassandra/service/StorageService.java

@@ -5201,7 +5201,7 @@ public void setHintedHandoffThrottleInKB(int throttleInKB)
         logger.info("Updated hinted_handoff_throttle_in_kb to {}", throttleInKB);
     }
 
-    public CompositeData getToppartitions(String sampler, List<String> keyspaceFilters, List<String> tableFilters, int duration, int capacity, int count) throws OpenDataException
+    public Map<String, CompositeData> getToppartitions(List<String> keyspaceFilters, List<String> tableFilters, int duration, int capacity, int count) throws OpenDataException
     {
         return null;
     }

src/java/org/apache/cassandra/service/StorageServiceMBean.java

@@ -673,7 +673,7 @@ public interface StorageServiceMBean extends NotificationEmitter
     /** Sets the hinted handoff throttle in kb per second, per delivery thread. */
     public void setHintedHandoffThrottleInKB(int throttleInKB);
 
-    public CompositeData getToppartitions(String sampler, List<String> keyspaceFilters, List<String> tableFilters, int duration, int capacity, int count) throws OpenDataException;
+    public Map<String, CompositeData> getToppartitions(List<String> keyspaceFilters, List<String> tableFilters, int duration, int capacity, int count) throws OpenDataException;
 
     /**
      * Resume bootstrap streaming when there is failed data streaming.

src/java/org/apache/cassandra/tools/NodeProbe.java

@@ -482,11 +482,12 @@ public Map<Sampler, CompositeData> getPartitionSample(String ks, String cf, int
 
     public Map<Sampler, CompositeData> getToppartitions(List<String> keyspaceFilters, List<String> tableFilters, int capacity, int duration, int count, List<Sampler> samplers) throws OpenDataException
     {
-        Map<Sampler, CompositeData> result = Maps.newHashMap();
+        Map<String, CompositeData> toppartitions = ssProxy.getToppartitions(keyspaceFilters, tableFilters, duration, capacity, count);
 
+        Map<Sampler, CompositeData> result = Maps.newHashMap();
         for (Sampler sampler : samplers)
         {
-            result.put(sampler, ssProxy.getToppartitions(sampler.name(), keyspaceFilters, tableFilters, duration, capacity, count));
+            result.put(sampler, toppartitions.get(sampler.name().toLowerCase()));
         }
 
         return result;