content: /**
   * Licensed 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.apache.aurora.scheduler.updater;
  
  import java.util.Optional;
  
  import static org.apache.aurora.scheduler.updater.InstanceActionHandler.AddTask;
  import static org.apache.aurora.scheduler.updater.InstanceActionHandler.KillTask;
  import static org.apache.aurora.scheduler.updater.InstanceActionHandler.WatchRunningTask;
  
  enum InstanceAction {
    KILL_TASK_AND_RESERVE(Optional.of(new KillTask(true))),
    KILL_TASK(Optional.of(new KillTask(false))),
    // TODO(wfarner): Build this action into the scheduler state machine instead.  Rather than
    // killing a task and re-recreating it, choose the updated or rolled-back task when we are
    // deciding to reschedule the task.
    ADD_TASK(Optional.of(new AddTask())),
    WATCH_TASK(Optional.of(new WatchRunningTask())),
    AWAIT_STATE_CHANGE(Optional.empty());
  
    private final Optional<InstanceActionHandler> handler;
  
    InstanceAction(Optional<InstanceActionHandler> handler) {
      this.handler = handler;
    }
  
    public Optional<InstanceActionHandler> getHandler() {
      return handler;
    }
  }
  