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.graphql;
  
  import graphql.schema.DataFetcher;
  import graphql.schema.DataFetchingEnvironment;
  import java.util.Set;
  import org.openqa.selenium.grid.data.NodeStatus;
  import org.openqa.selenium.grid.data.Slot;
  import org.openqa.selenium.grid.distributor.Distributor;
  import org.openqa.selenium.internal.Require;
  
  public class SessionData implements DataFetcher {
  
    private final Distributor distributor;
  
    public SessionData(Distributor distributor) {
      this.distributor = Require.nonNull("Distributor", distributor);
    }
  
    @Override
    public Object get(DataFetchingEnvironment environment) {
      String sessionId = environment.getArgument("id");
  
      if (sessionId.isEmpty()) {
        throw new SessionNotFoundException("Session id is empty. A valid session id is required.");
      }
  
      Set<NodeStatus> nodeStatuses = distributor.getStatus().getNodes();
  
      SessionInSlot currentSession = findSession(sessionId, nodeStatuses);
  
      if (currentSession != null) {
        org.openqa.selenium.grid.data.Session session = currentSession.session;
  
        return new org.openqa.selenium.grid.graphql.Session(
            session.getId().toString(),
            session.getCapabilities(),
            session.getStartTime(),
            session.getUri(),
            currentSession.node.getNodeId().toString(),
            currentSession.node.getExternalUri(),
            currentSession.slot);
      } else {
        throw new SessionNotFoundException(
            "No ongoing session found with the requested session id.", sessionId);
      }
    }
  
    private SessionInSlot findSession(String sessionId, Set<NodeStatus> nodeStatuses) {
      for (NodeStatus status : nodeStatuses) {
        for (Slot slot : status.getSlots()) {
          org.openqa.selenium.grid.data.Session session = slot.getSession();
  
          if (session != null && sessionId.equals(session.getId().toString())) {
            return new SessionInSlot(session, status, slot);
          }
        }
      }
      return null;
    }
  
    private static class SessionInSlot {
      private final org.openqa.selenium.grid.data.Session session;
      private final NodeStatus node;
      private final Slot slot;
  
      SessionInSlot(org.openqa.selenium.grid.data.Session session, NodeStatus node, Slot slot) {
        this.session = session;
        this.node = node;
        this.slot = slot;
      }
    }
  }
  