class NullBackend

Defines a stub cache implementation.

The stub implementation is needed when database access is not yet available. Because Drupal's caching system never requires that cached data be present, these stub functions can short-circuit the process and sidestep the need for any persistent storage. Using this cache implementation during normal operations would have a negative impact on performance.

This also can be used for testing purposes.

Hierarchy

Expanded class hierarchy of NullBackend

1 file declares its use of NullBackend
NullBackendTest.php in drupal/core/modules/system/lib/Drupal/system/Tests/Cache/NullBackendTest.php
Definition of Drupal\system\Tests\Cache\NullBackendTest.

File

drupal/core/lib/Drupal/Core/Cache/NullBackend.php, line 21
Definition of Drupal\Core\Cache\NullBackend.

Namespace

Drupal\Core\Cache
View source
class NullBackend implements CacheBackendInterface {

  /**
   * Constructs a NullBackend object.
   *
   * @param string $bin
   *   The cache bin for which the object is created.
   */
  public function __construct($bin) {
  }

  /**
   * Implements Drupal\Core\Cache\CacheBackendInterface::get().
   */
  public function get($cid, $allow_invalid = FALSE) {
    return FALSE;
  }

  /**
   * Implements Drupal\Core\Cache\CacheBackendInterface::getMultiple().
   */
  public function getMultiple(&$cids, $allow_invalid = FALSE) {
    return array();
  }

  /**
   * Implements Drupal\Core\Cache\CacheBackendInterface::set().
   */
  public function set($cid, $data, $expire = CacheBackendInterface::CACHE_PERMANENT, array $tags = array()) {
  }

  /**
   * Implements Drupal\Core\Cache\CacheBackendInterface::delete().
   */
  public function delete($cid) {
  }

  /**
   * Implements Drupal\Core\Cache\CacheBackendInterface::deleteMultiple().
   */
  public function deleteMultiple(array $cids) {
  }

  /**
   * Implements Drupal\Core\Cache\CacheBackendInterface::deleteAll().
   */
  public function deleteAll() {
  }

  /**
   * Implements Drupal\Core\Cache\CacheBackendInterface::deleteExpired().
   */
  public function deleteExpired() {
  }

  /**
   * Implements Drupal\Core\Cache\CacheBackendInterface::deleteTags().
   */
  public function deleteTags(array $tags) {
  }

  /**
   * Implements Drupal\Core\Cache\CacheBackendInterface::invalidate().
   */
  public function invalidate($cid) {
  }

  /**
   * Implements Drupal\Core\Cache\CacheBackendInterface::invalidateMultiple().
   */
  public function invalidateMultiple(array $cids) {
  }

  /**
   * Implements Drupal\Core\Cache\CacheBackendInterface::invalidateTags().
   */
  public function invalidateTags(array $tags) {
  }

  /**
   * Implements Drupal\Core\Cache\CacheBackendInterface::invalidateAll().
   */
  public function invalidateAll() {
  }

  /**
   * Implements Drupal\Core\Cache\CacheBackendInterface::garbageCollection().
   */
  public function garbageCollection() {
  }

  /**
   * Implements Drupal\Core\Cache\CacheBackendInterface::isEmpty().
   */
  public function isEmpty() {
    return TRUE;
  }

}

Members

Namesort descending Modifiers Type Description Overrides
CacheBackendInterface::CACHE_PERMANENT constant Indicates that the item should never be removed unless explicitly deleted.
NullBackend::delete public function Implements Drupal\Core\Cache\CacheBackendInterface::delete(). Overrides CacheBackendInterface::delete
NullBackend::deleteAll public function Implements Drupal\Core\Cache\CacheBackendInterface::deleteAll(). Overrides CacheBackendInterface::deleteAll
NullBackend::deleteExpired public function Implements Drupal\Core\Cache\CacheBackendInterface::deleteExpired(). Overrides CacheBackendInterface::deleteExpired
NullBackend::deleteMultiple public function Implements Drupal\Core\Cache\CacheBackendInterface::deleteMultiple(). Overrides CacheBackendInterface::deleteMultiple
NullBackend::deleteTags public function Implements Drupal\Core\Cache\CacheBackendInterface::deleteTags(). Overrides CacheBackendInterface::deleteTags
NullBackend::garbageCollection public function Implements Drupal\Core\Cache\CacheBackendInterface::garbageCollection(). Overrides CacheBackendInterface::garbageCollection
NullBackend::get public function Implements Drupal\Core\Cache\CacheBackendInterface::get(). Overrides CacheBackendInterface::get
NullBackend::getMultiple public function Implements Drupal\Core\Cache\CacheBackendInterface::getMultiple(). Overrides CacheBackendInterface::getMultiple
NullBackend::invalidate public function Implements Drupal\Core\Cache\CacheBackendInterface::invalidate(). Overrides CacheBackendInterface::invalidate
NullBackend::invalidateAll public function Implements Drupal\Core\Cache\CacheBackendInterface::invalidateAll(). Overrides CacheBackendInterface::invalidateAll
NullBackend::invalidateMultiple public function Implements Drupal\Core\Cache\CacheBackendInterface::invalidateMultiple(). Overrides CacheBackendInterface::invalidateMultiple
NullBackend::invalidateTags public function Implements Drupal\Core\Cache\CacheBackendInterface::invalidateTags(). Overrides CacheBackendInterface::invalidateTags
NullBackend::isEmpty public function Implements Drupal\Core\Cache\CacheBackendInterface::isEmpty(). Overrides CacheBackendInterface::isEmpty
NullBackend::set public function Implements Drupal\Core\Cache\CacheBackendInterface::set(). Overrides CacheBackendInterface::set
NullBackend::__construct public function Constructs a NullBackend object.