cachestore_dummy Class Reference

The cache dummy store. More...

Inheritance diagram for cachestore_dummy:

Public Member Functions
	__construct ($name='Dummy store', array $configuration=array())
	Constructs a dummy store instance.
	cache_size_details (int $samplekeys=50)
	Gets the amount of memory used by this specific cache within the store, if known.
	cleanup ()
	Performs any necessary clean up when the store instance is being deleted.
	create_clone (array $details=array())
	Creates a clone of this store instance ready to be initialised.
	delete ($key)
	Deletes an item from the cache.
	delete_many (array $keys)
	Deletes many items from the cache.
	estimate_stored_size ($key, $value)
	Estimates the storage size used within this cache if the given value is stored with the given key.
	get ($key)
	Returns the data for the given key.
	get_last_io_bytes ()
	Gets the number of bytes read from or written to cache as a result of the last action.
	get_many ($keys)
	Gets' the values for many keys.
	get_warnings ()
	Can be overridden to return any warnings this store instance should make to the admin.
	initialise (cache_definition $definition)
	Initialises the store instance for a definition.
	instance_created ()
	Performs any necessary operation when the store instance has been created.
	instance_deleted ()
	Performs any necessary operation when the store instance is being deleted.
	is_initialised ()
	Returns true if this has been initialised.
	is_ready ()
	Returns true if this cache store instance is ready to use.
	is_searchable ()
	Returns true if the store instance is searchable.
	my_name ()
	Returns the name of this instance.
	purge ()
	Deletes all of the items from the cache.
	set ($key, $data)
	Sets an item in the cache.
	set_many (array $keyvaluearray)
	Sets many items in the cache.
	store_total_size ()
	Gets the amount of memory/storage currently used by this cache store if known.
	supports_data_guarantee ()
	Returns true if the store instance guarantees data.
	supports_dereferencing_objects ()
	Returns true if the store automatically dereferences objects.
	supports_multiple_identifiers ()
	Returns true if the store instance supports multiple identifiers.
	supports_native_ttl ()
	Returns true if the store instance supports native ttl.

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

Public Attributes
const	DEREFERENCES_OBJECTS = 16
	The cache store dereferences objects.
const	IO_BYTES_NOT_SUPPORTED = -1
	Returned from get_last_io_bytes if this cache store doesn't support counting bytes read/sent.
const	IS_SEARCHABLE = 8
	The cache is searchable by key.
const	MODE_APPLICATION = 1
	Application caches.
const	MODE_REQUEST = 4
	Request caches.
const	MODE_SESSION = 2
	Session caches.
const	STATIC_ACCEL = '** static accel. **'
	Static caches.
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.

Protected Attributes
cache_definition	$definition
	Cache definition.
string	$name
	The name of this store.
bool	$persist = false
	Gets set to true if this store is going to store data.
array	$store = array()
	The stored data array.

Detailed Description

The cache dummy store.

Copyright

2012 Sam Hemelryk

License

http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

Constructor & Destructor Documentation

__construct()

cachestore_dummy::__construct	(		$name = 'Dummy store',
		array	$configuration = array() )

Constructs a dummy store instance.

Parameters

string	$name
array	$configuration

Reimplemented from cache_store.

Member Function Documentation

are_requirements_met()

static cachestore_dummy::are_requirements_met ( )

static

Returns true if this store plugin is usable.

Return values

bool

Implements cache_store_interface.

cache_size_details()

cache_store::cache_size_details ( int $samplekeys = 50 )

inherited

Gets the amount of memory used by this specific cache within the store, if known.

This function may be slow and should not be called in normal usage, only for administration pages. The value is usually an estimate, and may not be available at all.

When estimating, a number of sample items will be used for the estimate. If set to 50 (default), then this function will retrieve 50 random items and use that to estimate the total size.

The return value has the following fields:

• supported (true if any other values are completed)
• items (number of items)
• mean (mean size of one item in bytes)
• sd (standard deviation of item size in bytes, based on sample)
• margin (95% confidence margin for mean - will be 0 if exactly computed)

Parameters

int

$samplekeys

Number of samples to use

Return values

stdClass

Object with information about the store size

Reimplemented in cachestore_file.

can_add_instance()

static cachestore_dummy::can_add_instance ( )

static

Returns true if the user can add an instance.

Return values

bool

Reimplemented from cache_store.

cleanup()

cachestore_dummy::cleanup

(

)

Performs any necessary clean up when the store instance is being deleted.

Deprecated

since 3.2

See also

cachestore_dummy\instance_deleted()

Reimplemented from cache_store.

create_clone()

cache_store::create_clone ( array $details = array() )

inherited

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()

cachestore_dummy::delete

(

$key

)

Deletes an item from the cache.

Parameters

string

$key

Return values

bool

Reimplemented from cache_store.

delete_many()

cachestore_dummy::delete_many

(

array

$keys

)

Deletes many items from the cache.

Parameters

array

$keys

Return values

bool

Reimplemented from cache_store.

estimate_stored_size()

cache_store::estimate_stored_size ( $key, $value )

inherited

Estimates the storage size used within this cache if the given value is stored with the given key.

This function is not exactly accurate; it does not necessarily take into account all the overheads involved. It is only intended to give a good idea of the relative size of different caches.

The default implementation serializes both key and value and sums the lengths (as a rough estimate which is probably good enough for everything unless the cache offers compression).

Parameters

mixed	$key	Key
mixed	$value	Value

Return values

int	Size in bytes

Reimplemented in cachestore_redis.

get()

cachestore_dummy::get

(

$key

)

Returns the data for the given key.

Parameters

string

$key

Return values

string|false

Reimplemented from cache_store.

get_last_io_bytes()

cache_store::get_last_io_bytes ( )

inherited

Gets the number of bytes read from or written to cache as a result of the last action.

This includes calls to the functions get(), get_many(), set(), and set_many(). The number is reset by calling any of these functions.

This should be the actual number of bytes of the value read from or written to cache, giving an impression of the network or other load. It will not be exactly the same amount as netowrk traffic because of protocol overhead, key text, etc.

If not supported, returns IO_BYTES_NOT_SUPPORTED.

Return values

int	Bytes read (or 0 if none/not supported)

Since

Moodle 4.0

Reimplemented in cachestore_file, and cachestore_redis.

get_many()

cachestore_dummy::get_many

(

$keys

)

Gets' the values for many keys.

Parameters

array

$keys

Return values

bool

Reimplemented from cache_store.

get_supported_features()

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

static

Returns the supported features.

Parameters

array

$configuration

Return values

int

Implements cache_store_interface.

get_supported_modes()

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

static

Returns the supported mode.

Parameters

array

$configuration

Return values

int

Implements cache_store_interface.

get_warnings()

cache_store::get_warnings ( )

inherited

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.

initialise()

cachestore_dummy::initialise

(

cache_definition

$definition

)

Initialises the store instance for a definition.

Parameters

cache_definition

$definition

Reimplemented from cache_store.

initialise_test_instance()

static cachestore_dummy::initialise_test_instance ( cache_definition $definition )

static

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

Parameters

cache_definition

$definition

Return values

false

Implements cache_store_interface.

instance_created()

cache_store::instance_created ( )

inherited

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

Since

Moodle 2.5

Reimplemented in cachestore_file.

instance_deleted()

cachestore_dummy::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 3.2

Reimplemented from cache_store.

is_initialised()

cachestore_dummy::is_initialised

(

)

Returns true if this has been initialised.

Return values

bool

Reimplemented from cache_store.

is_ready()

cache_store::is_ready ( )

inherited

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

Return values

bool

Reimplemented in cachestore_file, and cachestore_redis.

is_searchable()

cache_store::is_searchable ( )

inherited

Returns true if the store instance is searchable.

Return values

bool

is_supported_mode()

static cachestore_dummy::is_supported_mode ( $mode )

static

Returns true the given mode is supported.

Parameters

int

$mode

Return values

bool

Implements cache_store_interface.

my_name()

cachestore_dummy::my_name

(

)

Returns the name of this instance.

Return values

string

Reimplemented from cache_store.

purge()

cachestore_dummy::purge

(

)

Deletes all of the items from the cache.

Return values

bool

Reimplemented from cache_store.

ready_to_be_used_for_testing()

static cache_store::ready_to_be_used_for_testing ( )

staticinherited

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_apcu, and cachestore_redis.

set()

cachestore_dummy::set	(		$key,
			$data )

Sets an item in the cache.

Parameters

string	$key
mixed	$data

Return values

bool

Reimplemented from cache_store.

set_many()

cachestore_dummy::set_many

(

array

$keyvaluearray

)

Sets many items in the cache.

Parameters

array

$keyvaluearray

Return values

int

Reimplemented from cache_store.

store_total_size()

cache_store::store_total_size ( )

inherited

Gets the amount of memory/storage currently used by this cache store if known.

This value should be obtained quickly from the store itself, if available.

This is the total memory usage of the entire store, not for ther specific cache in question.

Where not supported (default), will always return null.

Return values

int|null

Amount of memory used in bytes or null

Reimplemented in cachestore_file, and cachestore_redis.

supports_data_guarantee()

cache_store::supports_data_guarantee ( )

inherited

Returns true if the store instance guarantees data.

Return values

bool

supports_dereferencing_objects()

cache_store::supports_dereferencing_objects ( )

inherited

Returns true if the store automatically dereferences objects.

Return values

bool

supports_multiple_identifiers()

cache_store::supports_multiple_identifiers ( )

inherited

Returns true if the store instance supports multiple identifiers.

Return values

bool

Reimplemented in cachestore_file, cachestore_session, and cachestore_static.

supports_native_ttl()

cache_store::supports_native_ttl ( )

inherited

Returns true if the store instance supports native ttl.

Return values

bool

unit_test_configuration()

static cachestore_dummy::unit_test_configuration ( )

static

Generates the appropriate configuration required for unit testing.

Return values

array

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

Implements cache_store_interface.

Member Data Documentation

$persist

bool cachestore_dummy::$persist = false

protected

Gets set to true if this store is going to store data.

This happens when the definition doesn't require static acceleration as the loader will not be storing information and something has to.

DEREFERENCES_OBJECTS

const cache_store::DEREFERENCES_OBJECTS = 16

inherited

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

inherited

Application caches.

These are shared caches.

MODE_REQUEST

const cache_store::MODE_REQUEST = 4

inherited

Request caches.

Static caches really.

MODE_SESSION

const cache_store::MODE_SESSION = 2

inherited

Session caches.

Just access to the PHP session.

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

• cache/classes/dummystore.php