# ChainedDependency

> ChainedDependency represents a dependency which is composed of a list of other dependencies.

[API reference](/docs/api/index.md) › [yii](/docs/api/yii/index.md) › [caching](/docs/api/yii/caching/index.md) › ChainedDependency

| class | `yii\caching\ChainedDependency` |
| --- | --- |
| Extends | [`Dependency`](/docs/api/yii/caching/dependency/index.md) » [`yii\base\BaseObject`](/docs/api/yii/base/baseobject/index.md) |
| Implements | [`yii\base\Configurable`](/docs/api/yii/base/configurable/index.md) |
| Since | 2.0 |
| Source | [`framework/caching/ChainedDependency.php`](https://github.com/yiisoft/yii2/blob/22.0/framework/caching/ChainedDependency.php#L23) |

ChainedDependency represents a dependency which is composed of a list of other dependencies.

When [`$dependOnAll`](/docs/api/yii/caching/chaineddependency/index.md#property-dependOnAll) is true, if any of the dependencies has changed, this dependency is
considered changed; When [`$dependOnAll`](/docs/api/yii/caching/chaineddependency/index.md#property-dependOnAll) is false, if one of the dependencies has NOT changed,
this dependency is considered NOT changed.

For more details and usage information on Cache, see the [guide article on caching](/docs/guide/caching-overview/index.md).

## Properties

| Property | Type | Description | Defined by |
| --- | --- | --- | --- |
| <span id="property-data"></span>[`$data`](/docs/api/yii/caching/dependency/index.md#property-data) | `mixed` | The dependency data that is saved in cache and later is compared with the latest dependency data. Default: `null`. | [`Dependency`](/docs/api/yii/caching/dependency/index.md) |
| [`$dependencies`](#property-dependencies) | [`Dependency`](/docs/api/yii/caching/dependency/index.md)`[]` | List of dependencies that this dependency is composed of. Default: `[]`. | `ChainedDependency` |
| [`$dependOnAll`](#property-dependOnAll) | `bool` | Whether this dependency is depending on every dependency in [`$dependencies`](/docs/api/yii/caching/chaineddependency/index.md#property-dependencies). Default: `true`. | `ChainedDependency` |
| <span id="property-reusable"></span>[`$reusable`](/docs/api/yii/caching/dependency/index.md#property-reusable) | `bool` | Whether this dependency is reusable or not. Default: `false`. | [`Dependency`](/docs/api/yii/caching/dependency/index.md) |

## Methods

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

## Property details

### $dependencies <span id="property-dependencies"></span>

```php
public yii\caching\Dependency[] $dependencies = []
```

List of dependencies that this dependency is composed of.

Each array element must be a dependency object.

### $dependOnAll <span id="property-dependOnAll"></span>

```php
public bool $dependOnAll = true
```

Whether this dependency is depending on every dependency in [`$dependencies`](/docs/api/yii/caching/chaineddependency/index.md#property-dependencies).

Defaults to true, meaning if any of the dependencies has changed, this dependency is considered changed.
When it is set false, it means if one of the dependencies has NOT changed, this dependency
is considered NOT changed.

## Method details

### evaluateDependency() <span id="method-evaluateDependency"></span>

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

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

**Parameters**

| Parameter | Type | Description |
| --- | --- | --- |
| `$cache` | [`CacheInterface`](/docs/api/yii/caching/cacheinterface/index.md) | The cache component that is currently evaluating this dependency |

**Returns**

`mixed`

### isChanged() <span id="method-isChanged"></span>

```php
public function isChanged(mixed $cache): bool
```

Checks whether the dependency is changed.

**Parameters**

| Parameter | Type | Description |
| --- | --- | --- |
| `$cache` | `mixed` | The cache component that is currently evaluating this dependency |

**Returns**

`bool`: Whether the dependency has changed.

**Since**

2.0.11

### generateDependencyData() <span id="method-generateDependencyData"></span>

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

Generates the data needed to determine if dependency has been changed.

This method does nothing in this class.

**Parameters**

| Parameter | Type | Description |
| --- | --- | --- |
| `$cache` | [`CacheInterface`](/docs/api/yii/caching/cacheinterface/index.md) | The cache component that is currently evaluating this dependency |

**Returns**

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