code: // 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.distributor;
  
  import static org.openqa.selenium.remote.http.Contents.string;
  
  import java.util.stream.Collectors;
  import org.openqa.selenium.grid.data.NodeStatus;
  import org.openqa.selenium.grid.data.Slot;
  import org.openqa.selenium.grid.node.Node;
  import org.openqa.selenium.grid.node.remote.RemoteNode;
  import org.openqa.selenium.grid.security.Secret;
  import org.openqa.selenium.internal.Require;
  import org.openqa.selenium.json.Json;
  import org.openqa.selenium.remote.http.HttpClient;
  import org.openqa.selenium.remote.http.HttpHandler;
  import org.openqa.selenium.remote.http.HttpRequest;
  import org.openqa.selenium.remote.http.HttpResponse;
  import org.openqa.selenium.remote.tracing.Tracer;
  
  class AddNode implements HttpHandler {
  
    private final Tracer tracer;
    private final Distributor distributor;
    private final Json json;
    private final HttpClient.Factory httpFactory;
    private final Secret registrationSecret;
  
    AddNode(
        Tracer tracer,
        Distributor distributor,
        Json json,
        HttpClient.Factory httpFactory,
        Secret registrationSecret) {
      this.tracer = Require.nonNull("Tracer", tracer);
      this.distributor = Require.nonNull("Distributor", distributor);
      this.json = Require.nonNull("Json converter", json);
      this.httpFactory = Require.nonNull("HTTP Factory", httpFactory);
      this.registrationSecret = Require.nonNull("Registration secret", registrationSecret);
    }
  
    @Override
    public HttpResponse execute(HttpRequest req) {
      NodeStatus status = json.toType(string(req), NodeStatus.class);
  
      Node node =
          new RemoteNode(
              tracer,
              httpFactory,
              status.getNodeId(),
              status.getExternalUri(),
              registrationSecret,
              status.getSlots().stream().map(Slot::getStereotype).collect(Collectors.toSet()));
  
      distributor.add(node);
  
      return new HttpResponse();
    }
  }
  