Added slices parameter to HLRC reindex request

client/rest-high-level/src/main/java/org/elasticsearch/client/RequestConverters.java

@@ -554,7 +554,8 @@ final class RequestConverters {
             .withRefresh(reindexRequest.isRefresh())
             .withTimeout(reindexRequest.getTimeout())
             .withWaitForActiveShards(reindexRequest.getWaitForActiveShards())
-            .withRequestsPerSecond(reindexRequest.getRequestsPerSecond());
+            .withRequestsPerSecond(reindexRequest.getRequestsPerSecond())
+            .withSlices(reindexRequest.getSlices());
 
         if (reindexRequest.getScrollTime() != null) {
             params.putParam("scroll", reindexRequest.getScrollTime());
@@ -897,6 +898,10 @@ final class RequestConverters {
             return putParam("routing", routing);
         }
 
+        Params withSlices(int slices) {
+            return putParam("slices", String.valueOf(slices));
+        }
+
         Params withStoredFields(String[] storedFields) {
             if (storedFields != null && storedFields.length > 0) {
                 return putParam("stored_fields", String.join(",", storedFields));

client/rest-high-level/src/test/java/org/elasticsearch/client/RequestConvertersTests.java

@@ -439,6 +439,13 @@ public class RequestConvertersTests extends ESTestCase {
         if (reindexRequest.getRemoteInfo() == null && randomBoolean()) {
             reindexRequest.setSourceQuery(new TermQueryBuilder("foo", "fooval"));
         }
+        if (randomBoolean()) {
+            int slices = randomInt(100);
+            reindexRequest.setSlices(slices);
+            expectedParams.put("slices", String.valueOf(slices));
+        } else {
+            expectedParams.put("slices", "1");
+        }
         setRandomTimeout(reindexRequest::setTimeout, ReplicationRequest.DEFAULT_TIMEOUT, expectedParams);
         setRandomWaitForActiveShards(reindexRequest::setWaitForActiveShards, ActiveShardCount.DEFAULT, expectedParams);
         expectedParams.put("scroll", reindexRequest.getScrollTime().getStringRep());