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 java.lang.reflect.Type;
  import java.util.HashMap;
  import java.util.LinkedHashSet;
  import java.util.Map;
  import java.util.Objects;
  import java.util.Set;
  import java.util.StringJoiner;
  import org.openqa.selenium.Capabilities;
  import org.openqa.selenium.internal.Require;
  import org.openqa.selenium.json.JsonInput;
  import org.openqa.selenium.json.TypeToken;
  
  public class SessionRequestCapability {
  
    private static final Type SET_OF_CAPABILITIES = new TypeToken<Set<Capabilities>>() {}.getType();
    private final RequestId requestId;
    private final Set<Capabilities> desiredCapabilities;
  
    public SessionRequestCapability(RequestId requestId, Set<Capabilities> desiredCapabilities) {
      this.requestId = Require.nonNull("Request ID", requestId);
      this.desiredCapabilities =
          unmodifiableSet(new LinkedHashSet<>(Require.nonNull("Capabilities", desiredCapabilities)));
    }
  
    public RequestId getRequestId() {
      return requestId;
    }
  
    public Set<Capabilities> getDesiredCapabilities() {
      return desiredCapabilities;
    }
  
    @Override
    public String toString() {
      return new StringJoiner(", ", SessionRequestCapability.class.getSimpleName() + "[", "]")
          .add("requestId=" + requestId)
          .add("desiredCapabilities=" + desiredCapabilities)
          .toString();
    }
  
    @Override
    public boolean equals(Object o) {
      if (!(o instanceof SessionRequestCapability)) {
        return false;
      }
      SessionRequestCapability that = (SessionRequestCapability) o;
  
      return this.requestId.equals(that.requestId)
          && this.desiredCapabilities.equals(that.desiredCapabilities);
    }
  
    @Override
    public int hashCode() {
      return Objects.hash(requestId, desiredCapabilities);
    }
  
    private Map<String, Object> toJson() {
      Map<String, Object> toReturn = new HashMap<>();
      toReturn.put("requestId", requestId);
      toReturn.put("capabilities", desiredCapabilities);
      return unmodifiableMap(toReturn);
    }
  
    private static SessionRequestCapability fromJson(JsonInput input) {
      RequestId id = null;
      Set<Capabilities> capabilities = null;
  
      input.beginObject();
      while (input.hasNext()) {
        switch (input.nextName()) {
          case "capabilities":
            capabilities = input.read(SET_OF_CAPABILITIES);
            break;
  
          case "requestId":
            id = input.read(RequestId.class);
            break;
  
          default:
            input.skipValue();
            break;
        }
      }
      input.endObject();
  
      return new SessionRequestCapability(id, capabilities);
    }
  }
  