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.node;
  
  import static java.net.HttpURLConnection.HTTP_INTERNAL_ERROR;
  import static java.net.HttpURLConnection.HTTP_OK;
  
  import java.io.UncheckedIOException;
  import java.util.Objects;
  import org.openqa.selenium.json.Json;
  import org.openqa.selenium.remote.http.HttpHandler;
  import org.openqa.selenium.remote.http.HttpRequest;
  import org.openqa.selenium.remote.http.HttpResponse;
  
  public class Drain implements HttpHandler {
  
    private final Node node;
    private final Json json;
  
    public Drain(Node node, Json json) {
      this.node = Objects.requireNonNull(node);
      this.json = Objects.requireNonNull(json);
    }
  
    @Override
    public HttpResponse execute(HttpRequest req) throws UncheckedIOException {
      this.node.drain();
  
      HttpResponse response = new HttpResponse();
  
      if (this.node.isDraining()) {
        response.setStatus(HTTP_OK);
      } else {
        response.setStatus(HTTP_INTERNAL_ERROR);
      }
  
      return response;
    }
  }
  