cache_store Class Reference

Inheritance diagram for cache_store:

Public Member Functions
	__construct ($name, array $configuration=array())
	Constructs an instance of the cache store. More...
	cleanup ()
	create_clone (array $details=array())
	Creates a clone of this store instance ready to be initialised. More...
	delete ($key)
	Deletes an item from the cache store. More...
	delete_many (array $keys)
	Deletes several keys from the cache in a single action. More...
	get ($key)
	Retrieves an item from the cache store given its key. More...
	get_many ($keys)
	Retrieves several items from the cache store in a single transaction. More...
	get_warnings ()
	Can be overridden to return any warnings this store instance should make to the admin. More...
	initialise (cache_definition $definition)
	Initialises a new instance of the cache store given the definition the instance is to be used for. More...
	instance_created ()
	Performs any necessary operation when the store instance has been created. More...
	instance_deleted ()
	Performs any necessary operation when the store instance is being deleted. More...
	is_initialised ()
	Returns true if this cache store instance has been initialised. More...
	is_ready ()
	Returns true if this cache store instance is ready to use. More...
	is_searchable ()
	Returns true if the store instance is searchable. More...
	my_name ()
	Returns the name of this store instance. More...
	purge ()
	Purges the cache deleting all items within it. More...
	set ($key, $data)
	Sets an item in the cache given its key and data value. More...
	set_many (array $keyvaluearray)
	Sets many items in the cache in a single transaction. More...
	supports_data_guarantee ()
	Returns true if the store instance guarantees data. More...
	supports_dereferencing_objects ()
	Returns true if the store automatically dereferences objects. More...
	supports_multiple_identifiers ()
	Returns true if the store instance supports multiple identifiers. More...
	supports_native_ttl ()
	Returns true if the store instance supports native ttl. More...

Static Public Member Functions
static	are_requirements_met ()
	Static method to check if the store requirements are met. More...
static	can_add_instance ()
	Returns true if the user can add an instance of the store plugin. More...
static	get_supported_features (array $configuration=array())
	Returns the supported features as a binary flag. More...
static	get_supported_modes (array $configuration=array())
	Returns the supported modes as a binary flag. More...
static	initialise_test_instance (cache_definition $definition)
	Generates an instance of the cache store that can be used for testing. More...
static	is_supported_mode ($mode)
	Static method to check if a store is usable with the given mode. More...
static	ready_to_be_used_for_testing ()
	Returns true if this cache store instance is both suitable for testing, and ready for testing. More...
static	unit_test_configuration ()
	Generates the appropriate configuration required for unit testing. More...

Public Attributes
const	DEREFERENCES_OBJECTS = 16
	The cache store dereferences objects. More...
const	IS_SEARCHABLE = 8
	The cache is searchable by key.
const	MODE_APPLICATION = 1
	Application caches. More...
const	MODE_REQUEST = 4
	Request caches. More...
const	MODE_SESSION = 2
	Session caches. More...
const	SUPPORTS_DATA_GUARANTEE = 2
	Ensures data remains in the cache once set.
const	SUPPORTS_MULTIPLE_IDENTIFIERS = 1
	Supports multi-part keys.
const	SUPPORTS_NATIVE_TTL = 4
	Supports a native ttl system.

Constructor & Destructor Documentation

__construct()

cache_store::__construct (   $name, array  $configuration = array()  )

abstract

Constructs an instance of the cache store.

The constructor should be responsible for creating anything needed by the store that is not specific to a definition. Tasks such as opening a connection to check it is available are best done here. Tasks that are definition specific such as creating a storage area for the definition data or creating key tables and indexs are best done within the initialise method.

Once a store has been constructed the cache API will check it is ready to be intialised with a definition by called $this->is_ready(). If the setup of the store failed (connection could not be established for example) then that method should return false so that the store instance is not selected for use.

Parameters

string	$name	The name of the cache store
array	$configuration	The configuration for this store instance.

Reimplemented in cachestore_dummy, cachestore_static, cachestore_session, cachestore_redis, cachestore_mongodb, cachestore_memcached, cachestore_file, and cachestore_apcu.

Member Function Documentation

are_requirements_met()

static cache_store_interface::are_requirements_met ( )

staticinherited

Static method to check if the store requirements are met.

Return values

bool	True if the stores software/hardware requirements have been met and it can be used. False otherwise.

Implemented in cachestore_static, cachestore_session, cachestore_redis, cachestore_mongodb, cachestore_memcached, cachestore_file, cachestore_apcu, and cachestore_dummy.

can_add_instance()

static cache_store::can_add_instance ( )

static

Returns true if the user can add an instance of the store plugin.

Return values

bool

Reimplemented in cachestore_static, cachestore_session, and cachestore_dummy.

cleanup()

cache_store::cleanup

(

)

Deprecated:

since 2.5

See also

cache_store::instance_deleted()

Reimplemented in cachestore_dummy.

create_clone()

cache_store::create_clone

(

array

$details = array()

)

Creates a clone of this store instance ready to be initialised.

This method is used so that a cache store needs only be constructed once. Future requests for an instance of the store will be given a cloned instance.

If you are writing a cache store that isn't compatible with the clone operation you can override this method to handle any situations you want before cloning.

Parameters

array

$details

An array containing the details of the store from the cache config.

Return values

cache_store

delete()

cache_store::delete (   $key )

abstract

Deletes an item from the cache store.

Parameters

string

$key

The key to delete.

Return values

bool	Returns true if the operation was a success, false otherwise.

Reimplemented in cachestore_static, cachestore_session, cachestore_redis, cachestore_mongodb, cachestore_memcached, cachestore_file, cachestore_apcu, and cachestore_dummy.

delete_many()

cache_store::delete_many ( array  $keys )

abstract

Deletes several keys from the cache in a single action.

Parameters

array

$keys

The keys to delete

Return values

int	The number of items successfully deleted.

Reimplemented in cachestore_static, cachestore_session, cachestore_redis, cachestore_mongodb, cachestore_memcached, cachestore_file, cachestore_apcu, and cachestore_dummy.

get()

cache_store::get (   $key )

abstract

Retrieves an item from the cache store given its key.

Parameters

string

$key

The key to retrieve

Return values

mixed

The data that was associated with the key, or false if the key did not exist.

Reimplemented in cachestore_static, cachestore_session, cachestore_redis, cachestore_mongodb, cachestore_memcached, cachestore_file, cachestore_apcu, and cachestore_dummy.

get_many()

cache_store::get_many (   $keys )

abstract

Retrieves several items from the cache store in a single transaction.

If not all of the items are available in the cache then the data value for those that are missing will be set to false.

Parameters

array

$keys

The array of keys to retrieve

Return values

array

An array of items from the cache. There will be an item for each key, those that were not in the store will be set to false.

Reimplemented in cachestore_static, cachestore_session, cachestore_redis, cachestore_mongodb, cachestore_memcached, cachestore_file, cachestore_apcu, and cachestore_dummy.

get_supported_features()

static cache_store_interface::get_supported_features ( array  $configuration = array() )

staticinherited

Returns the supported features as a binary flag.

Parameters

array

$configuration

The configuration of a store to consider specifically.

Return values

int	The supported features.

Implemented in cachestore_static, cachestore_session, cachestore_redis, cachestore_mongodb, cachestore_memcached, cachestore_file, cachestore_apcu, and cachestore_dummy.

get_supported_modes()

static cache_store_interface::get_supported_modes ( array  $configuration = array() )

staticinherited

Returns the supported modes as a binary flag.

Parameters

array

$configuration

The configuration of a store to consider specifically.

Return values

int	The supported modes.

Implemented in cachestore_static, cachestore_session, cachestore_redis, cachestore_mongodb, cachestore_memcached, cachestore_file, cachestore_apcu, and cachestore_dummy.

get_warnings()

cache_store::get_warnings

(

)

Can be overridden to return any warnings this store instance should make to the admin.

This should be used to notify things like configuration conflicts etc. The warnings returned here will be displayed on the cache configuration screen.

Return values

string[]

An array of warning strings from the store instance.

Reimplemented in cachestore_memcached.

initialise()

cache_store::initialise ( cache_definition  $definition )

abstract

Initialises a new instance of the cache store given the definition the instance is to be used for.

This function should be used to run any definition specific setup the store instance requires. Tasks such as creating storage areas, or creating indexes are best done here.

Its important to note that the initialise method is expected to always succeed. If there are setup tasks that may fail they should be done within the __construct method and should they fail is_ready should return false.

Parameters

cache_definition

$definition

Reimplemented in cachestore_static, cachestore_session, cachestore_redis, cachestore_mongodb, cachestore_memcached, cachestore_file, cachestore_apcu, and cachestore_dummy.

initialise_test_instance()

static cache_store_interface::initialise_test_instance ( cache_definition  $definition )

staticinherited

Generates an instance of the cache store that can be used for testing.

Returns an instance of the cache store, or false if one cannot be created.

Parameters

cache_definition

$definition

Return values

cache_store|false

Implemented in cachestore_static, cachestore_session, cachestore_redis, cachestore_mongodb, cachestore_memcached, cachestore_file, cachestore_apcu, and cachestore_dummy.

instance_created()

cache_store::instance_created

(

)

Performs any necessary operation when the store instance has been created.

Since

Moodle 2.5

Reimplemented in cachestore_file.

instance_deleted()

cache_store::instance_deleted

(

)

Performs any necessary operation when the store instance is being deleted.

This method may be called before the store has been initialised.

Since

Moodle 2.5

See also

cleanup()

Reimplemented in cachestore_static, cachestore_session, cachestore_redis, cachestore_mongodb, cachestore_memcached, cachestore_file, cachestore_apcu, and cachestore_dummy.

is_initialised()

cache_store::is_initialised ( )

abstract

Returns true if this cache store instance has been initialised.

Return values

bool

Reimplemented in cachestore_static, cachestore_session, cachestore_redis, cachestore_mongodb, cachestore_memcached, cachestore_file, cachestore_apcu, and cachestore_dummy.

is_ready()

cache_store::is_ready

(

)

Returns true if this cache store instance is ready to use.

Return values

bool

Reimplemented in cachestore_redis, cachestore_mongodb, cachestore_memcached, and cachestore_file.

is_searchable()

cache_store::is_searchable

(

)

Returns true if the store instance is searchable.

Return values

bool

is_supported_mode()

static cache_store_interface::is_supported_mode (   $mode )

staticinherited

Static method to check if a store is usable with the given mode.

Parameters

int

$mode

One of cache_store::MODE_*

Implemented in cachestore_static, cachestore_session, cachestore_redis, cachestore_mongodb, cachestore_memcached, cachestore_file, cachestore_apcu, and cachestore_dummy.

my_name()

cache_store::my_name ( )

abstract

Returns the name of this store instance.

Return values

string

Reimplemented in cachestore_static, cachestore_session, cachestore_redis, cachestore_mongodb, cachestore_memcached, cachestore_file, cachestore_apcu, and cachestore_dummy.

purge()

cache_store::purge ( )

abstract

Purges the cache deleting all items within it.

Return values

boolean

True on success. False otherwise.

Reimplemented in cachestore_static, cachestore_session, cachestore_redis, cachestore_mongodb, cachestore_memcached, cachestore_file, cachestore_apcu, and cachestore_dummy.

ready_to_be_used_for_testing()

static cache_store::ready_to_be_used_for_testing ( )

static

Returns true if this cache store instance is both suitable for testing, and ready for testing.

Cache stores that support being used as the default store for unit and acceptance testing should override this function and return true if there requirements have been met.

Return values

bool

Reimplemented in cachestore_redis, cachestore_mongodb, cachestore_memcached, and cachestore_apcu.

set()

cache_store::set (   $key,   $data  )

abstract

Sets an item in the cache given its key and data value.

Parameters

string	$key	The key to use.
mixed	$data	The data to set.

Return values

bool	True if the operation was a success false otherwise.

Reimplemented in cachestore_redis, cachestore_mongodb, cachestore_memcached, cachestore_file, cachestore_apcu, and cachestore_dummy.

set_many()

cache_store::set_many ( array  $keyvaluearray )

abstract

Sets many items in the cache in a single transaction.

Parameters

array

$keyvaluearray

An array of key value pairs. Each item in the array will be an associative array with two keys, 'key' and 'value'.

Return values

int	The number of items successfully set. It is up to the developer to check this matches the number of items sent ... if they care that is.

Reimplemented in cachestore_static, cachestore_session, cachestore_redis, cachestore_mongodb, cachestore_memcached, cachestore_file, cachestore_apcu, and cachestore_dummy.

supports_data_guarantee()

cache_store::supports_data_guarantee

(

)

Returns true if the store instance guarantees data.

Return values

bool

supports_dereferencing_objects()

cache_store::supports_dereferencing_objects

(

)

Returns true if the store automatically dereferences objects.

Return values

bool

supports_multiple_identifiers()

cache_store::supports_multiple_identifiers

(

)

Returns true if the store instance supports multiple identifiers.

Return values

bool

Reimplemented in cachestore_static, cachestore_session, cachestore_mongodb, cachestore_memcached, and cachestore_file.

supports_native_ttl()

cache_store::supports_native_ttl

(

)

Returns true if the store instance supports native ttl.

Return values

bool

unit_test_configuration()

static cache_store_interface::unit_test_configuration ( )

staticinherited

Generates the appropriate configuration required for unit testing.

Return values

array

Array of unit test configuration data to be used by initialise().

Implemented in cachestore_static, cachestore_session, cachestore_redis, cachestore_mongodb, cachestore_memcached, cachestore_file, cachestore_apcu, and cachestore_dummy.

Member Data Documentation

DEREFERENCES_OBJECTS

const cache_store::DEREFERENCES_OBJECTS = 16

The cache store dereferences objects.

When set, loaders will assume that all data coming from this store has already had all references resolved. So even for complex object structures it will not try to remove references again.

MODE_APPLICATION

const cache_store::MODE_APPLICATION = 1

Application caches.

These are shared caches.

MODE_REQUEST

const cache_store::MODE_REQUEST = 4

Request caches.

Static caches really.

MODE_SESSION

const cache_store::MODE_SESSION = 2

Session caches.

Just access to the PHP session.

---

The documentation for this class was generated from the following file:

• cache/classes/store.php