Defines a chained cache implementation for combining multiple cache backends.
Can be used to combine two or more backends together to behave as if they were a single backend.
For example a slower, persistent storage engine could be combined with a faster, volatile storage engine. When retrieving items from cache, they will be fetched from the volatile backend first, only falling back to the persistent backend if an item is not available. An item not present in the volatile backend but found in the persistent one will be propagated back up to ensure fast retrieval on the next request. On cache sets and deletes, both backends will be invoked to ensure consistency.
Hierarchy
- class \Drupal\Core\Cache\BackendChain implements CacheBackendInterface, CacheTagsInvalidatorInterface
See also
\Drupal\Core\Cache\ChainedFastBackend
Related topics
- Cache API
- Information about the Drupal Cache API
File
- core/lib/Drupal/Core/Cache/BackendChain.php, line 22
Namespace
Drupal\Core\Cache
Members
| Name | Modifiers | Type | Description |
|---|---|---|---|
| BackendChain::$backends | protected | property | Ordered list of CacheBackendInterface instances. |
| BackendChain::appendBackend | public | function | Appends a cache backend to the cache chain. |
| BackendChain::delete | public | function | Deletes an item from the cache. Overrides CacheBackendInterface::delete |
| BackendChain::deleteAll | public | function | Deletes all cache items in a bin. Overrides CacheBackendInterface::deleteAll |
| BackendChain::deleteMultiple | public | function | Deletes multiple items from the cache. Overrides CacheBackendInterface::deleteMultiple |
| BackendChain::garbageCollection | public | function | Performs garbage collection on a cache bin. Overrides CacheBackendInterface::garbageCollection |
| BackendChain::get | public | function | Returns data from the persistent cache. Overrides CacheBackendInterface::get |
| BackendChain::getMultiple | public | function | Returns data from the persistent cache when given an array of cache IDs. Overrides CacheBackendInterface::getMultiple |
| BackendChain::invalidate | public | function | Marks a cache item as invalid. Overrides CacheBackendInterface::invalidate |
| BackendChain::invalidateAll | public | function | Marks all cache items as invalid. Overrides CacheBackendInterface::invalidateAll |
| BackendChain::invalidateMultiple | public | function | Marks cache items as invalid. Overrides CacheBackendInterface::invalidateMultiple |
| BackendChain::invalidateTags | public | function | Marks cache items with any of the specified tags as invalid. Overrides CacheTagsInvalidatorInterface::invalidateTags |
| BackendChain::prependBackend | public | function | Prepends a cache backend to the cache chain. |
| BackendChain::removeBin | public | function | Remove a cache bin. Overrides CacheBackendInterface::removeBin |
| BackendChain::set | public | function | Stores data in the persistent cache. Overrides CacheBackendInterface::set |
| BackendChain::setMultiple | public | function | Store multiple items in the persistent cache. Overrides CacheBackendInterface::setMultiple |
| BackendChain::__construct | public | function | Constructs a DatabaseBackend object. |
| CacheBackendInterface::CACHE_PERMANENT | constant | Indicates that the item should never be removed unless explicitly deleted. |
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