interface CacheWarmerInterface

CacheWarmerAggregateTest.php in drupal/core/vendor/symfony/http-kernel/Symfony/Component/HttpKernel/Tests/CacheWarmer/CacheWarmerAggregateTest.php

interface CacheWarmerInterface extends WarmableInterface {

  /**
   * Checks whether this warmer is optional or not.
   *
   * Optional warmers can be ignored on certain conditions.
   *
   * A warmer should return true if the cache can be
   * generated incrementally and on-demand.
   *
   * @return Boolean true if the warmer is optional, false otherwise
   */
  public function isOptional();

}