@Override
  public Stage createExisting(@Assisted StageEntity stageEntity) {
    return new Stage(stageEntity, injector.getInstance(HostRoleCommandDAO.class),
        injector.getInstance(ActionDBAccessor.class), injector.getInstance(Clusters.class),
        injector.getInstance(HostRoleCommandFactory.class),
        injector.getInstance(ExecutionCommandWrapperFactory.class));
  }
Constructor via the factory.
@param stageEntity Existing stage entity to copy fields form.
@return An instance of a Stage that is created using the provided stage as input.
ambari-server/src/main/java/org/apache/ambari/server/actionmanager/StageFactoryImpl.java