Dependency

API reference › yii › caching › Dependency

abstract class	`yii\caching\Dependency`
Extends	`yii\base\BaseObject`
Implements	`yii\base\Configurable`
Since	2.0
Source	`framework/caching/Dependency.php`

7 subclasses

Dependency is the base class for cache dependency classes.

Child classes should override its generateDependencyData() for generating the actual dependency data.

For more details and usage information on Cache, see the guide article on caching.

Properties

Property	Type	Description	Defined by
`$data`	`mixed`	The dependency data that is saved in cache and later is compared with the latest dependency data. Default: `null`.	`Dependency`
`$reusable`	`bool`	Whether this dependency is reusable or not. Default: `false`.	`Dependency`

Methods

Method	Description	Defined by
`__construct()`	Constructor.	`yii\base\BaseObject`
`__call()`	Calls the named method which is not a class method.	`yii\base\BaseObject`
`__get()`	Returns the value of an object property.	`yii\base\BaseObject`
`__isset()`	Checks if a property is set, i.e. defined and not null.	`yii\base\BaseObject`
`__set()`	Sets value of an object property.	`yii\base\BaseObject`
`__unset()`	Sets an object property to null.	`yii\base\BaseObject`
`canGetProperty()`	Returns a value indicating whether a property can be read.	`yii\base\BaseObject`
`canSetProperty()`	Returns a value indicating whether a property can be set.	`yii\base\BaseObject`
`className()` static	Returns the fully qualified name of this class.	`yii\base\BaseObject`
`evaluateDependency()`	Evaluates the dependency by generating and saving the data related with dependency.	`Dependency`
`hasMethod()`	Returns a value indicating whether a method is defined.	`yii\base\BaseObject`
`hasProperty()`	Returns a value indicating whether a property is defined.	`yii\base\BaseObject`
`init()`	Initializes the object.	`yii\base\BaseObject`
`isChanged()`	Checks whether the dependency is changed.	`Dependency`
`resetReusableData()` static	Resets all cached data for reusable dependencies.	`Dependency`
`generateDependencyData()` protected abstract	Generates the data needed to determine if dependency is changed.	`Dependency`
`generateReusableHash()` protected	Generates a unique hash that can be used for retrieving reusable dependency data.	`Dependency`

Property details

$reusable

public bool $reusable = false

Whether this dependency is reusable or not.

True value means that dependent data for this cache dependency will be generated only once per request. This allows you to use the same cache dependency for multiple separate cache calls while generating the same page without an overhead of re-evaluating dependency data each time. Defaults to false.

Method details

evaluateDependency()

public function evaluateDependency(yii\caching\CacheInterface $cache): mixed

Evaluates the dependency by generating and saving the data related with dependency.

This method is invoked by cache before writing data into it.

Parameters

Parameter	Type	Description
`$cache`	`CacheInterface`	The cache component that is currently evaluating this dependency

Returns

mixed

isChanged()

public function isChanged(yii\caching\CacheInterface $cache): bool

Checks whether the dependency is changed.

Parameters

Parameter	Type	Description
`$cache`	`CacheInterface`	The cache component that is currently evaluating this dependency

Returns

bool: Whether the dependency has changed.

Since

2.0.11

resetReusableData()

public static function resetReusableData(): mixed

Resets all cached data for reusable dependencies.

Returns

mixed

generateDependencyData()

abstract protected function generateDependencyData(yii\caching\CacheInterface $cache): mixed

Generates the data needed to determine if dependency is changed.

Derived classes should override this method to generate the actual dependency data.

Parameters

Parameter	Type	Description
`$cache`	`CacheInterface`	The cache component that is currently evaluating this dependency

Returns

mixed: The data needed to determine if dependency has been changed.

generateReusableHash()

protected function generateReusableHash(): string

Generates a unique hash that can be used for retrieving reusable dependency data.

Returns

string: A unique hash value for this cache dependency.

See also

$reusable