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 java.io.Serializable;
  import java.util.Map;
  import java.util.Objects;
  import java.util.TreeMap;
  import java.util.UUID;
  import org.openqa.selenium.internal.Require;
  import org.openqa.selenium.json.JsonInput;
  
  public class SlotId implements Serializable {
  
    private final NodeId nodeId;
    private final UUID uuid;
  
    public SlotId(NodeId host, UUID uuid) {
      this.nodeId = Require.nonNull("Host id", host);
      this.uuid = Require.nonNull("Actual id", uuid);
    }
  
    public NodeId getOwningNodeId() {
      return nodeId;
    }
  
    public UUID getSlotId() {
      return uuid;
    }
  
    @Override
    public String toString() {
      return "SlotId{nodeId=" + nodeId + ", id=" + uuid + '}';
    }
  
    @Override
    public boolean equals(Object o) {
      if (!(o instanceof SlotId)) {
        return false;
      }
      SlotId that = (SlotId) o;
      return Objects.equals(this.nodeId, that.nodeId) && Objects.equals(this.uuid, that.uuid);
    }
  
    @Override
    public int hashCode() {
      return Objects.hash(nodeId, uuid);
    }
  
    private Object toJson() {
      Map<String, Object> toReturn = new TreeMap<>();
      toReturn.put("hostId", nodeId);
      toReturn.put("id", uuid);
      return unmodifiableMap(toReturn);
    }
  
    private static SlotId fromJson(JsonInput input) {
      NodeId nodeId = null;
      UUID id = null;
  
      input.beginObject();
      while (input.hasNext()) {
        switch (input.nextName()) {
          case "hostId":
            nodeId = input.read(NodeId.class);
            break;
  
          case "id":
            id = input.read(UUID.class);
            break;
  
          default:
            input.skipValue();
            break;
        }
      }
      input.endObject();
  
      return new SlotId(nodeId, id);
    }
  }
  