<?php
namespace Psr\Cache;
/**
* CacheItemInterface defines an interface for interacting with objects inside a cache.
*
* Each Item object MUST be associated with a specific key, which can be set
* according to the implementing system and is typically passed by the
* Cache\CacheItemPoolInterface object.
*
* The Cache\CacheItemInterface object encapsulates the storage and retrieval of
* cache items. Each Cache\CacheItemInterface is generated by a
* Cache\CacheItemPoolInterface object, which is responsible for any required
* setup as well as associating the object with a unique Key.
* Cache\CacheItemInterface objects MUST be able to store and retrieve any type
* of PHP value defined in the Data section of the specification.
*
* Calling Libraries MUST NOT instantiate Item objects themselves. They may only
* be requested from a Pool object via the getItem() method. Calling Libraries
* SHOULD NOT assume that an Item created by one Implementing Library is
* compatible with a Pool from another Implementing Library.
*/
interface CacheItemInterface
{
/**
* Returns the key for the current cache item.
*
* The key is loaded by the Implementing Library, but should be available to
* the higher level callers when needed.
*
* @return string
* The key string for this cache item.
*/
public function getKey();
/**
* Retrieves the value of the item from the cache associated with this object's key.
*
* The value returned must be identical to the value originally stored by set().
*
* If isHit() returns false, this method MUST return null. Note that null
* is a legitimate cached value, so the isHit() method SHOULD be used to
* differentiate between "null value was found" and "no value was found."
*
* @return mixed
* The value corresponding to this cache item's key, or null if not found.
*/
public function get();
/**
* Confirms if the cache item lookup resulted in a cache hit.
*
* Note: This method MUST NOT have a race condition between calling isHit()
* and calling get().
*
* @return bool
* True if the request resulted in a cache hit. False otherwise.
*/
public function isHit();
/**
* Sets the value represented by this cache item.
*
* The $value argument may be any item that can be serialized by PHP,
* although the method of serialization is left up to the Implementing
* Library.
*
* @param mixed $value
* The serializable value to be stored.
*
* @return static
* The invoked object.
*/
public function set($value);
/**
* Sets the expiration time for this cache item.
*
* @param \DateTimeInterface|null $expiration
* The point in time after which the item MUST be considered expired.
* If null is passed explicitly, a default value MAY be used. If none is set,
* the value should be stored permanently or for as long as the
* implementation allows.
*
* @return static
* The called object.
*/
public function expiresAt($expiration);
/**
* Sets the expiration time for this cache item.
*
* @param int|\DateInterval|null $time
* The period of time from the present after which the item MUST be considered
* expired. An integer parameter is understood to be the time in seconds until
* expiration. If null is passed explicitly, a default value MAY be used.
* If none is set, the value should be stored permanently or for as long as the
* implementation allows.
*
* @return static
* The called object.
*/
public function expiresAfter($time);
}