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.data;
  
  import static java.util.Collections.unmodifiableMap;
  import static java.util.Collections.unmodifiableSet;
  import static org.openqa.selenium.json.Json.MAP_TYPE;
  
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.Map;
  import java.util.Set;
  import org.openqa.selenium.Capabilities;
  import org.openqa.selenium.ImmutableCapabilities;
  import org.openqa.selenium.internal.Require;
  import org.openqa.selenium.json.JsonInput;
  import org.openqa.selenium.json.TypeToken;
  import org.openqa.selenium.remote.Dialect;
  
  public class CreateSessionRequest {
  
    private final Set<Dialect> downstreamDialects;
    private final Capabilities capabilities;
    private final Map<String, Object> metadata;
  
    public CreateSessionRequest(
        Set<Dialect> downstreamDialects, Capabilities capabilities, Map<String, Object> metadata) {
      this.downstreamDialects =
          unmodifiableSet(new HashSet<>(Require.nonNull("Downstream dialects", downstreamDialects)));
      this.capabilities = ImmutableCapabilities.copyOf(Require.nonNull("Capabilities", capabilities));
      this.metadata = unmodifiableMap(new HashMap<>(Require.nonNull("Metadata", metadata)));
    }
  
    public Set<Dialect> getDownstreamDialects() {
      return downstreamDialects;
    }
  
    public Capabilities getDesiredCapabilities() {
      return capabilities;
    }
  
    public Map<String, Object> getMetadata() {
      return metadata;
    }
  
    private static CreateSessionRequest fromJson(JsonInput input) {
      Set<Dialect> downstreamDialects = null;
      Capabilities capabilities = null;
      Map<String, Object> metadata = null;
  
      input.beginObject();
      while (input.hasNext()) {
        switch (input.nextName()) {
          case "desiredCapabilities":
            capabilities = input.read(Capabilities.class);
            break;
  
          case "downstreamDialects":
            downstreamDialects = input.read(new TypeToken<Set<Dialect>>() {}.getType());
            break;
  
          case "metadata":
            metadata = input.read(MAP_TYPE);
            break;
  
          default:
            input.skipValue();
        }
      }
      input.endObject();
  
      return new CreateSessionRequest(downstreamDialects, capabilities, metadata);
    }
  
    public String toString() {
      return String.format("<CreateSessionRequest with %s>", capabilities);
    }
  }
  