CacheableDependencyInterface.php

<?php

namespace Drupal\Core\Cache;


/**
 * Defines an interface for objects which may be used by other cached objects.
 *
 * All cacheability metadata exposed in this interface is bubbled to parent
 * objects when they are cached: if a child object needs to be varied by certain
 * cache contexts, invalidated by certain cache tags, expire after a certain
 * maximum age, then so should any parent object.
 *
 * @ingroup cache
 */
interface CacheableDependencyInterface {
    
    /**
     * The cache contexts associated with this object.
     *
     * These identify a specific variation/representation of the object.
     *
     * Cache contexts are tokens: placeholders that are converted to cache keys by
     * the @cache_contexts_manager service. The replacement value depends on the
     * request context (the current URL, language, and so on). They're converted
     * before storing an object in cache.
     *
     * @return string[]
     *   An array of cache context tokens, used to generate a cache ID.
     *
     * @see \Drupal\Core\Cache\Context\CacheContextsManager::convertTokensToKeys()
     */
    public function getCacheContexts();
    
    /**
     * The cache tags associated with this object.
     *
     * When this object is modified, these cache tags will be invalidated.
     *
     * @return string[]
     *   A set of cache tags.
     */
    public function getCacheTags();
    
    /**
     * The maximum age for which this object may be cached.
     *
     * @return int
     *   The maximum time in seconds that this object may be cached.
     *   An object may be cached permanently by returning
     *   \Drupal\Core\Cache\Cache::PERMANENT.
     */
    public function getCacheMaxAge();

}