[grid] Hide file configs behind a factory

java/server/src/org/openqa/selenium/grid/config/Configs.java

@@ -0,0 +1,45 @@
+// Licensed to the Software Freedom Conservancy (SFC) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The SFC licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License.  You may obtain a copy of the License at
+//
+//   http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied.  See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+package org.openqa.selenium.grid.config;
+
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Objects;
+
+public class Configs {
+
+  public static Config from(Path path) {
+    Objects.requireNonNull(path, "Path to read must be set.");
+
+    if (!Files.exists(path)) {
+      throw new ConfigException("Path to read from does not exist: " + path);
+    }
+
+    String fileName = path.getFileName().toString();
+    if (fileName.endsWith(".tml") || fileName.endsWith(".toml")) {
+      return TomlConfig.from(path);
+    }
+
+    if (fileName.endsWith(".json")) {
+      return JsonConfig.from(path);
+    }
+
+    throw new ConfigException(
+      "Unable to determine file type. The file extension must be one of '.toml' or '.json' " + path);
+  }
+}

java/server/src/org/openqa/selenium/grid/config/JsonConfig.java

@@ -35,7 +35,7 @@ public class JsonConfig implements Config {
   private static final Json JSON = new Json();
   private final Config delegate;
 
-  public JsonConfig(Reader reader) {
+  JsonConfig(Reader reader) {
     Objects.requireNonNull(reader, "JSON source must be set.");
 
     try {

java/server/src/org/openqa/selenium/grid/config/TomlConfig.java

@@ -35,7 +35,7 @@ public class TomlConfig implements Config {
 
   private final Toml toml;
 
-  public TomlConfig(Reader reader) {
+  TomlConfig(Reader reader) {
     try {
       toml = JToml.parse(reader);
     } catch (IOException e) {