Allow _count to take preference parameter. [#2698]

src/main/java/org/elasticsearch/action/count/CountRequest.java

@@ -62,6 +62,9 @@ public class CountRequest extends BroadcastOperationRequest<CountRequest> {
     @Nullable
     protected String routing;
 
+    @Nullable
+    private String preference;
+
     private BytesReference querySource;
     private boolean querySourceUnsafe;
 
@@ -220,6 +223,15 @@ public class CountRequest extends BroadcastOperationRequest<CountRequest> {
         return this;
     }
 
+    public CountRequest preference(String preference) {
+        this.preference = preference;
+        return this;
+    }
+
+    public String preference() {
+        return this.preference;
+    }
+
     @Override
     public void readFrom(StreamInput in) throws IOException {
         super.readFrom(in);

src/main/java/org/elasticsearch/action/count/TransportCountAction.java

@@ -104,7 +104,7 @@ public class TransportCountAction extends TransportBroadcastOperationAction<Coun
     @Override
     protected GroupShardsIterator shards(ClusterState clusterState, CountRequest request, String[] concreteIndices) {
         Map<String, Set<String>> routingMap = clusterState.metaData().resolveSearchRouting(request.routing(), request.indices());
-        return clusterService.operationRouting().searchShards(clusterState, request.indices(), concreteIndices, routingMap, null);
+        return clusterService.operationRouting().searchShards(clusterState, request.indices(), concreteIndices, routingMap, request.preference());
     }
 
     @Override

src/main/java/org/elasticsearch/rest/action/count/RestCountAction.java

@@ -89,6 +89,7 @@ public class RestCountAction extends BaseRestHandler {
             countRequest.routing(request.param("routing"));
             countRequest.minScore(request.paramAsFloat("min_score", DEFAULT_MIN_SCORE));
             countRequest.types(splitTypes(request.param("type")));
+            countRequest.preference(request.param("preference"));
         } catch (Exception e) {
             try {
                 XContentBuilder builder = RestXContentBuilder.restContentBuilder(request);