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.sessionqueue;
  
  import static org.openqa.selenium.remote.http.Route.combine;
  import static org.openqa.selenium.remote.http.Route.delete;
  import static org.openqa.selenium.remote.http.Route.get;
  import static org.openqa.selenium.remote.http.Route.options;
  import static org.openqa.selenium.remote.http.Route.post;
  
  import java.time.Instant;
  import java.util.List;
  import java.util.Map;
  import java.util.Optional;
  import java.util.UUID;
  import org.openqa.selenium.Capabilities;
  import org.openqa.selenium.SessionNotCreatedException;
  import org.openqa.selenium.grid.data.CreateSessionResponse;
  import org.openqa.selenium.grid.data.RequestId;
  import org.openqa.selenium.grid.data.SessionRequest;
  import org.openqa.selenium.grid.data.SessionRequestCapability;
  import org.openqa.selenium.grid.security.RequiresSecretFilter;
  import org.openqa.selenium.grid.security.Secret;
  import org.openqa.selenium.internal.Either;
  import org.openqa.selenium.internal.Require;
  import org.openqa.selenium.remote.http.HttpRequest;
  import org.openqa.selenium.remote.http.HttpResponse;
  import org.openqa.selenium.remote.http.Routable;
  import org.openqa.selenium.remote.http.Route;
  import org.openqa.selenium.remote.tracing.Tracer;
  import org.openqa.selenium.status.HasReadyState;
  
  public abstract class NewSessionQueue implements HasReadyState, Routable {
  
    protected final Tracer tracer;
    private final Route routes;
  
    protected NewSessionQueue(Tracer tracer, Secret registrationSecret) {
      this.tracer = Require.nonNull("Tracer", tracer);
  
      Require.nonNull("Registration secret", registrationSecret);
      RequiresSecretFilter requiresSecret = new RequiresSecretFilter(registrationSecret);
  
      routes =
          combine(
              post("/session")
                  .to(
                      () ->
                          req -> {
                            SessionRequest sessionRequest =
                                new SessionRequest(
                                    new RequestId(UUID.randomUUID()), req, Instant.now());
                            return addToQueue(sessionRequest);
                          }),
              options("/session").to(() -> req -> new HttpResponse()),
              post("/se/grid/newsessionqueue/session")
                  .to(() -> new AddToSessionQueue(tracer, this))
                  .with(requiresSecret),
              post("/se/grid/newsessionqueue/session/{requestId}/retry")
                  .to(params -> new AddBackToSessionQueue(tracer, this, requestIdFrom(params)))
                  .with(requiresSecret),
              post("/se/grid/newsessionqueue/session/{requestId}/failure")
                  .to(params -> new SessionNotCreated(tracer, this, requestIdFrom(params)))
                  .with(requiresSecret),
              post("/se/grid/newsessionqueue/session/{requestId}/success")
                  .to(params -> new SessionCreated(tracer, this, requestIdFrom(params)))
                  .with(requiresSecret),
              post("/se/grid/newsessionqueue/session/{requestId}")
                  .to(params -> new RemoveFromSessionQueue(tracer, this, requestIdFrom(params)))
                  .with(requiresSecret),
              post("/se/grid/newsessionqueue/session/next")
                  .to(() -> new GetNextMatchingRequest(tracer, this))
                  .with(requiresSecret),
              get("/se/grid/newsessionqueue/queue").to(() -> new GetSessionQueue(tracer, this)),
              delete("/se/grid/newsessionqueue/queue")
                  .to(() -> new ClearSessionQueue(tracer, this))
                  .with(requiresSecret));
    }
  
    private RequestId requestIdFrom(Map<String, String> params) {
      return new RequestId(UUID.fromString(params.get("requestId")));
    }
  
    public abstract HttpResponse addToQueue(SessionRequest request);
  
    public abstract boolean retryAddToQueue(SessionRequest request);
  
    public abstract Optional<SessionRequest> remove(RequestId reqId);
  
    public abstract List<SessionRequest> getNextAvailable(Map<Capabilities, Long> stereotypes);
  
    public abstract void complete(
        RequestId reqId, Either<SessionNotCreatedException, CreateSessionResponse> result);
  
    public abstract int clearQueue();
  
    public abstract List<SessionRequestCapability> getQueueContents();
  
    @Override
    public boolean matches(HttpRequest req) {
      return routes.matches(req);
    }
  
    @Override
    public HttpResponse execute(HttpRequest req) {
      return routes.execute(req);
    }
  }
  