HLRC: Standardize access in *RequestConverters (#34768)

With the move to separate RequestConverters classes for each client,
some of the access restrictions on the new classes are more open than
the prior RequestConverters classes. This standardizes the
*RequestConverters classes as package-private, final, and with a private
constructor so that no instances of the can be inadvertently created.

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

@@ -31,6 +31,8 @@ import java.io.IOException;
 
 final class ClusterRequestConverters {
 
+    private ClusterRequestConverters() {}
+
     static Request clusterPutSettings(ClusterUpdateSettingsRequest clusterUpdateSettingsRequest) throws IOException {
         Request request = new Request(HttpPut.METHOD_NAME, "/_cluster/settings");
 

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

@@ -24,7 +24,9 @@ import org.elasticsearch.protocol.xpack.graph.GraphExploreRequest;
 
 import java.io.IOException;
 
-public class GraphRequestConverters {
+final class GraphRequestConverters {
+
+    private GraphRequestConverters() {}
 
     static Request explore(GraphExploreRequest exploreRequest) throws IOException {
         String endpoint = RequestConverters.endpoint(exploreRequest.indices(), exploreRequest.types(), "_xpack/graph/_explore");

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

@@ -53,7 +53,10 @@ import org.elasticsearch.common.Strings;
 import java.io.IOException;
 import java.util.Locale;
 
-public class IndicesRequestConverters {
+final class IndicesRequestConverters {
+
+    private IndicesRequestConverters() {}
+
     static Request deleteIndex(DeleteIndexRequest deleteIndexRequest) {
         String endpoint = RequestConverters.endpoint(deleteIndexRequest.indices());
         Request request = new Request(HttpDelete.METHOD_NAME, endpoint);

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

@@ -30,7 +30,9 @@ import org.elasticsearch.action.ingest.SimulatePipelineRequest;
 
 import java.io.IOException;
 
-public class IngestRequestConverters {
+final class IngestRequestConverters {
+
+    private IngestRequestConverters() {}
 
     static Request getPipeline(GetPipelineRequest getPipelineRequest) {
         String endpoint = new RequestConverters.EndpointBuilder()

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

@@ -29,7 +29,10 @@ import org.elasticsearch.client.license.DeleteLicenseRequest;
 import org.elasticsearch.client.license.GetLicenseRequest;
 import org.elasticsearch.client.license.PutLicenseRequest;
 
-public class LicenseRequestConverters {
+final class LicenseRequestConverters {
+
+    private LicenseRequestConverters() {}
+
     static Request putLicense(PutLicenseRequest putLicenseRequest) {
         String endpoint = new RequestConverters.EndpointBuilder().addPathPartAsIs("_xpack", "license").build();
         Request request = new Request(HttpPut.METHOD_NAME, endpoint);

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

@@ -22,7 +22,9 @@ package org.elasticsearch.client;
 import org.apache.http.client.methods.HttpGet;
 import org.elasticsearch.protocol.xpack.migration.IndexUpgradeInfoRequest;
 
-public class MigrationRequestConverters {
+final class MigrationRequestConverters {
+
+    private MigrationRequestConverters() {}
 
     static Request getMigrationAssistance(IndexUpgradeInfoRequest indexUpgradeInfoRequest) {
         RequestConverters.EndpointBuilder endpointBuilder = new RequestConverters.EndpointBuilder()

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

@@ -36,7 +36,9 @@ import org.elasticsearch.common.Strings;
 
 import java.io.IOException;
 
-public class SnapshotRequestConverters {
+final class SnapshotRequestConverters {
+
+    private SnapshotRequestConverters() {}
 
     static Request getRepositories(GetRepositoriesRequest getRepositoriesRequest) {
         String[] repositories = getRepositoriesRequest.repositories() == null ? Strings.EMPTY_ARRAY : getRepositoriesRequest.repositories();

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

@@ -24,7 +24,9 @@ import org.apache.http.client.methods.HttpPost;
 import org.elasticsearch.action.admin.cluster.node.tasks.cancel.CancelTasksRequest;
 import org.elasticsearch.action.admin.cluster.node.tasks.list.ListTasksRequest;
 
-public class TasksRequestConverters {
+final class TasksRequestConverters {
+
+    private TasksRequestConverters() {}
 
     static Request cancelTasks(CancelTasksRequest cancelTasksRequest) {
         Request request = new Request(HttpPost.METHOD_NAME, "/_tasks/_cancel");

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

@@ -32,7 +32,9 @@ import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.protocol.xpack.watcher.DeleteWatchRequest;
 import org.elasticsearch.protocol.xpack.watcher.PutWatchRequest;
 
-public class WatcherRequestConverters {
+final class WatcherRequestConverters {
+
+    private WatcherRequestConverters() {}
 
     static Request startWatchService(StartWatchServiceRequest startWatchServiceRequest) {
         String endpoint = new RequestConverters.EndpointBuilder()

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

@@ -27,7 +27,9 @@ import java.util.EnumSet;
 import java.util.Locale;
 import java.util.stream.Collectors;
 
-public class XPackRequestConverters {
+final class XPackRequestConverters {
+
+    private XPackRequestConverters() {}
 
     static Request info(XPackInfoRequest infoRequest) {
         Request request = new Request(HttpGet.METHOD_NAME, "/_xpack");