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.time.Instant;
  import java.util.Map;
  import java.util.Objects;
  import java.util.TreeMap;
  import org.openqa.selenium.Capabilities;
  import org.openqa.selenium.ImmutableCapabilities;
  import org.openqa.selenium.internal.Require;
  import org.openqa.selenium.json.JsonInput;
  
  public class Slot implements Serializable {
  
    private final SlotId id;
    private final Capabilities stereotype;
    private final Session session;
    private final Instant lastStarted;
  
    public Slot(SlotId id, Capabilities stereotype, Instant lastStarted, Session session) {
      this.id = Require.nonNull("Slot ID", id);
      this.stereotype = ImmutableCapabilities.copyOf(Require.nonNull("Stereotype", stereotype));
      this.lastStarted = Require.nonNull("Last started", lastStarted);
      this.session = session;
    }
  
    private static Slot fromJson(JsonInput input) {
      SlotId id = null;
      Capabilities stereotype = null;
      Instant lastStarted = null;
      Session session = null;
  
      input.beginObject();
      while (input.hasNext()) {
        String name = input.nextName();
        switch (name) {
          case "id":
            id = input.read(SlotId.class);
            break;
  
          case "lastStarted":
            lastStarted = input.read(Instant.class);
            break;
  
          case "session":
            session = input.read(Session.class);
            break;
  
          case "stereotype":
            stereotype = input.read(Capabilities.class);
            break;
  
          default:
            input.skipValue();
            break;
        }
      }
      input.endObject();
  
      return new Slot(id, stereotype, lastStarted, session);
    }
  
    private Map<String, Object> toJson() {
      Map<String, Object> toReturn = new TreeMap<>();
      toReturn.put("id", getId());
      toReturn.put("lastStarted", getLastStarted());
      toReturn.put("session", getSession());
      toReturn.put("stereotype", getStereotype());
      return unmodifiableMap(toReturn);
    }
  
    public SlotId getId() {
      return id;
    }
  
    public Capabilities getStereotype() {
      return stereotype;
    }
  
    public Instant getLastStarted() {
      return lastStarted;
    }
  
    public Session getSession() {
      return session;
    }
  
    public boolean isSupporting(Capabilities caps, SlotMatcher slotMatcher) {
      return slotMatcher.matches(getStereotype(), caps);
    }
  
    @Override
    public boolean equals(Object o) {
      if (!(o instanceof Slot)) {
        return false;
      }
  
      Slot that = (Slot) o;
      return Objects.equals(this.id, that.id)
          && Objects.equals(this.stereotype, that.stereotype)
          && Objects.equals(this.session, that.session)
          && Objects.equals(this.lastStarted.toEpochMilli(), that.lastStarted.toEpochMilli());
    }
  
    @Override
    public int hashCode() {
      return Objects.hash(id, stereotype, session, lastStarted.toEpochMilli());
    }
  }
  