# Class yii\di\Container

Inheritance | yii\di\Container » yii\base\Component » yii\base\BaseObject
Implements | yii\base\Configurable
Available since version | 2.0
Source Code | https://github.com/yiisoft/yii2/blob/master/framework/di/Container.php

Container implements a dependency injection container.

A dependency injection (DI) container is an object that knows how to instantiate and configure objects and all their dependent objects. For more information about DI, please refer to Martin Fowler's article.

Container supports constructor injection as well as property injection.

To use Container, you first need to set up the class dependencies by calling set(). You then call get() to create a new class object. The Container will automatically instantiate dependent objects, inject them into the object being created, configure, and finally return the newly created object.

By default, Yii::$container refers to a Container instance which is used by Yii::createObject() to create new object instances. You may use this method to replace the `new` operator when creating a new object, which gives you the benefit of automatic dependency resolution and default property configuration.

Below is an example of using Container:

    namespace app\models;

    use yii\base\BaseObject;
    use yii\db\Connection;
    use yii\di\Container;

    interface UserFinderInterface
    {
        function findUser();
    }

    class UserFinder extends BaseObject implements UserFinderInterface
    {
        public $db;

        public function __construct(Connection $db, $config = [])
        {
            $this->db = $db;
            parent::__construct($config);
        }

        public function findUser()
        {
        }
    }

    class UserLister extends BaseObject
    {
        public $finder;

        public function __construct(UserFinderInterface $finder, $config = [])
        {
            $this->finder = $finder;
            parent::__construct($config);
        }
    }

    $container = new Container;
    $container->set('yii\db\Connection', [
        'dsn' => '...',
    ]);
    $container->set('app\models\UserFinderInterface', [
        'class' => 'app\models\UserFinder',
    ]);
    $container->set('userLister', 'app\models\UserLister');

    $lister = $container->get('userLister');

    // which is equivalent to:

    $db = new \yii\db\Connection(['dsn' => '...']);
    $finder = new UserFinder($db);
    $lister = new UserLister($finder);

For more details and usage information on Container, see the guide article on di-containers.

## Public Properties

Hide inherited properties

Property | Type | Description | Defined By
--- | --- | --- | ---
$behaviors | yii\base\Behavior[] | List of behaviors attached to this component. | yii\base\Component
$definitions | array | The list of the object definitions or the loaded shared objects (type or ID => definition or instance). | yii\di\Container
$resolveArrays | boolean | Whether to attempt to resolve elements in array dependencies. | yii\di\Container
$singleton | string | Class name, interface name or alias name | yii\di\Container
$singletons | array | Array of singleton definitions. | yii\di\Container

## Public Methods

Hide inherited methods

Method | Description | Defined By
--- | --- | ---
__call() | Calls the named method which is not a class method. | yii\base\Component
__clone() | This method is called after the object is created by cloning an existing one. | yii\base\Component
__construct() | Constructor. | yii\base\BaseObject
__get() | Returns the value of a component property. | yii\base\Component
__isset() | Checks if a property is set, i.e. defined and not null. | yii\base\Component
__set() | Sets the value of a component property. | yii\base\Component
__unset() | Sets a component property to be null. | yii\base\Component
attachBehavior() | Attaches a behavior to this component. | yii\base\Component
attachBehaviors() | Attaches a list of behaviors to the component. | yii\base\Component
behaviors() | Returns a list of behaviors that this component should behave as. | yii\base\Component
canGetProperty() | Returns a value indicating whether a property can be read. | yii\base\Component
canSetProperty() | Returns a value indicating whether a property can be set. | yii\base\Component
className() | Returns the fully qualified name of this class. | yii\base\BaseObject
clear() | Removes the definition for the specified name. | yii\di\Container
detachBehavior() | Detaches a behavior from the component. | yii\base\Component
detachBehaviors() | Detaches all behaviors from the component. | yii\base\Component
ensureBehaviors() | Makes sure that the behaviors declared in behaviors() are attached to this component. | yii\base\Component
get() | Returns an instance of the requested class. | yii\di\Container
getBehavior() | Returns the named behavior object. | yii\base\Component
getBehaviors() | Returns all behaviors attached to this component. | yii\base\Component
getDefinitions() | Returns the list of the object definitions or the loaded shared objects. | yii\di\Container
has() | Returns a value indicating whether the container has the definition of the specified name. | yii\di\Container
hasEventHandlers() | Returns a value indicating whether there is any handler attached to the named event. | yii\base\Component
hasMethod() | Returns a value indicating whether a method is defined. | yii\base\Component
hasProperty() | Returns a value indicating whether a property is defined for this component. | yii\base\Component
hasSingleton() | Returns a value indicating whether the given name corresponds to a registered singleton. | yii\di\Container
init() | Initializes the object. | yii\base\BaseObject
invoke() | Invoke a callback with resolving dependencies in parameters. | yii\di\Container
off() | Detaches an existing event handler from this component. | yii\base\Component
on() | Attaches an event handler to an event. | yii\base\Component
resolveCallableDependencies() | Resolve dependencies for a function. | yii\di\Container
set() | Registers a class definition with this container. | yii\di\Container
setDefinitions() | Registers class definitions within this container. | yii\di\Container
setResolveArrays() |  | yii\di\Container
setSingleton() | Registers a class definition with this container and marks the class as a singleton class. | yii\di\Container
setSingletons() | Registers class definitions as singletons within this container by calling setSingleton(). | yii\di\Container
trigger() | Triggers an event. | yii\base\Component

## Protected Methods

Hide inherited methods

Method | Description | Defined By
--- | --- | ---
build() | Creates an instance of the specified class. | yii\di\Container
getDependencies() | Returns the dependencies of the specified class. | yii\di\Container
mergeParams() | Merges the user-specified constructor parameters with the ones registered via set(). | yii\di\Container
normalizeDefinition() | Normalizes the class definition. | yii\di\Container
resolveDependencies() | Resolves dependencies by replacing them with the actual object instances. | yii\di\Container

## Property Details

Hide inherited properties

$definitions public property

The list of the object definitions or the loaded shared objects (type or ID => definition or instance).

public array $definitions = null
$resolveArrays public property

Whether to attempt to resolve elements in array dependencies.

public boolean $resolveArrays = null
$singleton public write-only property

Class name, interface name or alias name

public $this setSingleton ( $class, $definition = [], array $params = [] )
$singletons public write-only property (available since version 2.0.11)

Array of singleton definitions. See setDefinitions() for allowed formats of array.

public void setSingletons ( array $singletons )

## Method Details

Hide inherited methods

__call() public method

Defined in: yii\base\Component::__call()

Calls the named method which is not a class method.

This method will check if any attached behavior has the named method and will execute it if available.

Do not call this method directly as it is a PHP magic method that will be implicitly called when an unknown method is being invoked.

public mixed __call ( $name, $params )
$name | string | The method name
$params | array | Method parameters
return | mixed | The method return value
throws | yii\base\UnknownMethodException | when calling unknown method

Source code

                    public function __call($name, $params)
    {
        $this->ensureBehaviors();
        foreach ($this->_behaviors as $object) {
            if ($object->hasMethod($name)) {
                return call_user_func_array([$object, $name], $params);
            }
        }
        throw new UnknownMethodException('Calling unknown method: ' . get_class($this) . "::$name()");
    }

__clone() public method

Defined in: yii\base\Component::__clone()

This method is called after the object is created by cloning an existing one.

It removes all behaviors because they are attached to the old object.

public void __clone ( )

Source code

                    public function __clone()
    {
        $this->_events = [];
        $this->_eventWildcards = [];
        $this->_behaviors = null;
    }

__construct() public method

Defined in: yii\base\BaseObject::__construct()

Constructor.

The default implementation does two things:

- Initializes the object with the given configuration `$config`.
- Call init().

If this method is overridden in a child class, it is recommended that

- the last parameter of the constructor is a configuration array, like `$config` here.
- call the parent implementation at the end of the constructor.

public void __construct ( $config = [] )
$config | array | Name-value pairs that will be used to initialize the object properties

Source code

                    public function __construct($config = [])
    {
        if (!empty($config)) {
            Yii::configure($this, $config);
        }
        $this->init();
    }

__get() public method

Defined in: yii\base\Component::__get()

Returns the value of a component property.

This method will check in the following order and act accordingly:

- a property defined by a getter: return the getter result
- a property of a behavior: return the behavior property value

Do not call this method directly as it is a PHP magic method that will be implicitly called when executing `$value = $component->property;`.

See also __set().

public mixed __get ( $name )
$name | string | The property name
return | mixed | The property value or the value of a behavior's property
throws | yii\base\UnknownPropertyException | if the property is not defined
throws | yii\base\InvalidCallException | if the property is write-only.

Source code

                    public function __get($name)
    {
        $getter = 'get' . $name;
        if (method_exists($this, $getter)) {
            // read property, e.g. getName()
            return $this->$getter();
        }
        // behavior property
        $this->ensureBehaviors();
        foreach ($this->_behaviors as $behavior) {
            if ($behavior->canGetProperty($name)) {
                return $behavior->$name;
            }
        }
        if (method_exists($this, 'set' . $name)) {
            throw new InvalidCallException('Getting write-only property: ' . get_class($this) . '::' . $name);
        }
        throw new UnknownPropertyException('Getting unknown property: ' . get_class($this) . '::' . $name);
    }

__isset() public method

Defined in: yii\base\Component::__isset()

Checks if a property is set, i.e. defined and not null.

This method will check in the following order and act accordingly:

- a property defined by a setter: return whether the property is set
- a property of a behavior: return whether the property is set
- return `false` for non existing properties

Do not call this method directly as it is a PHP magic method that will be implicitly called when executing `isset($component->property)`.

See also https://www.php.net/manual/en/function.isset.php.

public boolean __isset ( $name )
$name | string | The property name or the event name
return | boolean | Whether the named property is set

Source code

                    public function __isset($name)
    {
        $getter = 'get' . $name;
        if (method_exists($this, $getter)) {
            return $this->$getter() !== null;
        }
        // behavior property
        $this->ensureBehaviors();
        foreach ($this->_behaviors as $behavior) {
            if ($behavior->canGetProperty($name)) {
                return $behavior->$name !== null;
            }
        }
        return false;
    }

__set() public method

Defined in: yii\base\Component::__set()

Sets the value of a component property.

This method will check in the following order and act accordingly:

- a property defined by a setter: set the property value
- an event in the format of "on xyz": attach the handler to the event "xyz"
- a behavior in the format of "as xyz": attach the behavior named as "xyz"
- a property of a behavior: set the behavior property value

Do not call this method directly as it is a PHP magic method that will be implicitly called when executing `$component->property = $value;`.

See also __get().

public void __set ( $name, $value )
$name | string | The property name or the event name
$value | mixed | The property value
throws | yii\base\UnknownPropertyException | if the property is not defined
throws | yii\base\InvalidCallException | if the property is read-only.

Source code

                    public function __set($name, $value)
    {
        $setter = 'set' . $name;
        if (method_exists($this, $setter)) {
            // set property
            $this->$setter($value);
            return;
        } elseif (strncmp($name, 'on ', 3) === 0) {
            // on event: attach event handler
            $this->on(trim(substr($name, 3)), $value);
            return;
        } elseif (strncmp($name, 'as ', 3) === 0) {
            // as behavior: attach behavior
            $name = trim(substr($name, 3));
            $this->attachBehavior($name, $value instanceof Behavior ? $value : Yii::createObject($value));
            return;
        }
        // behavior property
        $this->ensureBehaviors();
        foreach ($this->_behaviors as $behavior) {
            if ($behavior->canSetProperty($name)) {
                $behavior->$name = $value;
                return;
            }
        }
        if (method_exists($this, 'get' . $name)) {
            throw new InvalidCallException('Setting read-only property: ' . get_class($this) . '::' . $name);
        }
        throw new UnknownPropertyException('Setting unknown property: ' . get_class($this) . '::' . $name);
    }

__unset() public method

Defined in: yii\base\Component::__unset()

Sets a component property to be null.

This method will check in the following order and act accordingly:

- a property defined by a setter: set the property value to be null
- a property of a behavior: set the property value to be null

Do not call this method directly as it is a PHP magic method that will be implicitly called when executing `unset($component->property)`.

See also https://www.php.net/manual/en/function.unset.php.

public void __unset ( $name )
$name | string | The property name
throws | yii\base\InvalidCallException | if the property is read only.

Source code

                    public function __unset($name)
    {
        $setter = 'set' . $name;
        if (method_exists($this, $setter)) {
            $this->$setter(null);
            return;
        }
        // behavior property
        $this->ensureBehaviors();
        foreach ($this->_behaviors as $behavior) {
            if ($behavior->canSetProperty($name)) {
                $behavior->$name = null;
                return;
            }
        }
        throw new InvalidCallException('Unsetting an unknown or read-only property: ' . get_class($this) . '::' . $name);
    }

attachBehavior() public method

Defined in: yii\base\Component::attachBehavior()

Attaches a behavior to this component.

This method will create the behavior object based on the given configuration. After that, the behavior object will be attached to this component by calling the yii\base\Behavior::attach() method.

See also detachBehavior().

public yii\base\Behavior attachBehavior ( $name, $behavior )
$name | string | The name of the behavior.

$behavior

string|array|yii\base\Behavior

The behavior configuration. This can be one of the following:

- a yii\base\Behavior object
- a string specifying the behavior class
- an object configuration array that will be passed to Yii::createObject() to create the behavior object.

return | yii\base\Behavior | The behavior object

Source code

                    public function attachBehavior($name, $behavior)
    {
        $this->ensureBehaviors();
        return $this->attachBehaviorInternal($name, $behavior);
    }

attachBehaviors() public method

Defined in: yii\base\Component::attachBehaviors()

Attaches a list of behaviors to the component.

Each behavior is indexed by its name and should be a yii\base\Behavior object, a string specifying the behavior class, or an configuration array for creating the behavior.

See also attachBehavior().

public void attachBehaviors ( $behaviors )
$behaviors | array | List of behaviors to be attached to the component

Source code

                    public function attachBehaviors($behaviors)
    {
        $this->ensureBehaviors();
        foreach ($behaviors as $name => $behavior) {
            $this->attachBehaviorInternal($name, $behavior);
        }
    }

behaviors() public method

Defined in: yii\base\Component::behaviors()

Returns a list of behaviors that this component should behave as.

Child classes may override this method to specify the behaviors they want to behave as.

The return value of this method should be an array of behavior objects or configurations indexed by behavior names. A behavior configuration can be either a string specifying the behavior class or an array of the following structure:

    'behaviorName' => [
        'class' => 'BehaviorClass',
        'property1' => 'value1',
        'property2' => 'value2',
    ]

Note that a behavior class must extend from yii\base\Behavior. Behaviors can be attached using a name or anonymously. When a name is used as the array key, using this name, the behavior can later be retrieved using getBehavior() or be detached using detachBehavior(). Anonymous behaviors can not be retrieved or detached.

Behaviors declared in this method will be attached to the component automatically (on demand).

public array behaviors ( )
return | array | The behavior configurations.

Source code

                    public function behaviors()
    {
        return [];
    }

build() protected method

Creates an instance of the specified class.

This method will resolve dependencies of the specified class, instantiate them, and inject them into the new instance of the specified class.

protected object build ( $class, $params, $config )
$class | string | The class name
$params | array | Constructor parameters
$config | array | Configurations to be applied to the new instance
return | object | The newly created instance of the specified class
throws | yii\di\NotInstantiableException | If resolved to an abstract class or an interface (since 2.0.9)

Source code

                    protected function build($class, $params, $config)
    {
        /* @var $reflection ReflectionClass */
        list($reflection, $dependencies) = $this->getDependencies($class);
        $addDependencies = [];
        if (isset($config['__construct()'])) {
            $addDependencies = $config['__construct()'];
            unset($config['__construct()']);
        }
        foreach ($params as $index => $param) {
            $addDependencies[$index] = $param;
        }
        $this->validateDependencies($addDependencies);
        if ($addDependencies && is_int(key($addDependencies))) {
            $dependencies = array_values($dependencies);
            $dependencies = $this->mergeDependencies($dependencies, $addDependencies);
        } else {
            $dependencies = $this->mergeDependencies($dependencies, $addDependencies);
            $dependencies = array_values($dependencies);
        }
        $dependencies = $this->resolveDependencies($dependencies, $reflection);
        if (!$reflection->isInstantiable()) {
            throw new NotInstantiableException($reflection->name);
        }
        if (empty($config)) {
            return $reflection->newInstanceArgs($dependencies);
        }
        $config = $this->resolveDependencies($config);
        if (!empty($dependencies) && $reflection->implementsInterface('yii\base\Configurable')) {
            // set $config as the last parameter (existing one will be overwritten)
            $dependencies[count($dependencies) - 1] = $config;
            return $reflection->newInstanceArgs($dependencies);
        }
        $object = $reflection->newInstanceArgs($dependencies);
        foreach ($config as $name => $value) {
            $object->$name = $value;
        }
        return $object;
    }

canGetProperty() public method

Defined in: yii\base\Component::canGetProperty()

Returns a value indicating whether a property can be read.

A property can be read if:

- the class has a getter method associated with the specified name (in this case, property name is case-insensitive);
- the class has a member variable with the specified name (when `$checkVars` is true);
- an attached behavior has a readable property of the given name (when `$checkBehaviors` is true).

See also canSetProperty().

public boolean canGetProperty ( $name, $checkVars = true, $checkBehaviors = true )
$name | string | The property name
$checkVars | boolean | Whether to treat member variables as properties
$checkBehaviors | boolean | Whether to treat behaviors' properties as properties of this component
return | boolean | Whether the property can be read

Source code

                    public function canGetProperty($name, $checkVars = true, $checkBehaviors = true)
    {
        if (method_exists($this, 'get' . $name) || $checkVars && property_exists($this, $name)) {
            return true;
        } elseif ($checkBehaviors) {
            $this->ensureBehaviors();
            foreach ($this->_behaviors as $behavior) {
                if ($behavior->canGetProperty($name, $checkVars)) {
                    return true;
                }
            }
        }
        return false;
    }

canSetProperty() public method

Defined in: yii\base\Component::canSetProperty()

Returns a value indicating whether a property can be set.

A property can be written if:

- the class has a setter method associated with the specified name (in this case, property name is case-insensitive);
- the class has a member variable with the specified name (when `$checkVars` is true);
- an attached behavior has a writable property of the given name (when `$checkBehaviors` is true).

See also canGetProperty().

public boolean canSetProperty ( $name, $checkVars = true, $checkBehaviors = true )
$name | string | The property name
$checkVars | boolean | Whether to treat member variables as properties
$checkBehaviors | boolean | Whether to treat behaviors' properties as properties of this component
return | boolean | Whether the property can be written

Source code

                    public function canSetProperty($name, $checkVars = true, $checkBehaviors = true)
    {
        if (method_exists($this, 'set' . $name) || $checkVars && property_exists($this, $name)) {
            return true;
        } elseif ($checkBehaviors) {
            $this->ensureBehaviors();
            foreach ($this->_behaviors as $behavior) {
                if ($behavior->canSetProperty($name, $checkVars)) {
                    return true;
                }
            }
        }
        return false;
    }

className() public static method
Deprecated since 2.0.14. On PHP >=5.5, use `::class` instead.

Defined in: yii\base\BaseObject::className()

Returns the fully qualified name of this class.

public static string className ( )
return | string | The fully qualified name of this class.

Source code

                    public static function className()
    {
        return get_called_class();
    }

clear() public method

Removes the definition for the specified name.

public void clear ( $class )
$class | string | Class name, interface name or alias name

Source code

                    public function clear($class)
    {
        unset($this->_definitions[$class], $this->_singletons[$class]);
    }

detachBehavior() public method

Defined in: yii\base\Component::detachBehavior()

Detaches a behavior from the component.

The behavior's yii\base\Behavior::detach() method will be invoked.

public yii\base\Behavior|null detachBehavior ( $name )
$name | string | The behavior's name.
return | yii\base\Behavior|null | The detached behavior. Null if the behavior does not exist.

Source code

                    public function detachBehavior($name)
    {
        $this->ensureBehaviors();
        if (isset($this->_behaviors[$name])) {
            $behavior = $this->_behaviors[$name];
            unset($this->_behaviors[$name]);
            $behavior->detach();
            return $behavior;
        }
        return null;
    }

detachBehaviors() public method

Defined in: yii\base\Component::detachBehaviors()

Detaches all behaviors from the component.

public void detachBehaviors ( )

Source code

                    public function detachBehaviors()
    {
        $this->ensureBehaviors();
        foreach ($this->_behaviors as $name => $behavior) {
            $this->detachBehavior($name);
        }
    }

ensureBehaviors() public method

Defined in: yii\base\Component::ensureBehaviors()

Makes sure that the behaviors declared in behaviors() are attached to this component.

public void ensureBehaviors ( )

Source code

                    public function ensureBehaviors()
    {
        if ($this->_behaviors === null) {
            $this->_behaviors = [];
            foreach ($this->behaviors() as $name => $behavior) {
                $this->attachBehaviorInternal($name, $behavior);
            }
        }
    }

get() public method

Returns an instance of the requested class.

You may provide constructor parameters (`$params`) and object configurations (`$config`) that will be used during the creation of the instance.

If the class implements yii\base\Configurable, the `$config` parameter will be passed as the last parameter to the class constructor; Otherwise, the configuration will be applied after the object is instantiated.

Note that if the class is declared to be singleton by calling setSingleton(), the same instance of the class will be returned each time this method is called. In this case, the constructor parameters and object configurations will be used only if the class is instantiated the first time.

public object get ( $class, $params = [], $config = [] )
$class | string|yii\di\Instance | The class Instance, name, or an alias name (e.g. `foo`) that was previously registered via set() or setSingleton().

$params

array

A list of constructor parameter values. Use one of two definitions:

- Parameters as name-value pairs, for example: `['posts' => PostRepository::class]`.
- Parameters in the order they appear in the constructor declaration. If you want to skip some parameters, you should index the remaining ones with the integers that represent their positions in the constructor parameter list. Dependencies indexed by name and by position in the same array are not allowed.

$config | array | A list of name-value pairs that will be used to initialize the object properties.
return | object | An instance of the requested class.
throws | yii\base\InvalidConfigException | if the class cannot be recognized or correspond to an invalid definition
throws | yii\di\NotInstantiableException | If resolved to an abstract class or an interface (since 2.0.9)

Source code

                    public function get($class, $params = [], $config = [])
    {
        if ($class instanceof Instance) {
            $class = $class->id;
        }
        if (isset($this->_singletons[$class])) {
            // singleton
            return $this->_singletons[$class];
        } elseif (!isset($this->_definitions[$class])) {
            return $this->build($class, $params, $config);
        }
        $definition = $this->_definitions[$class];
        if (is_callable($definition, true)) {
            $params = $this->resolveDependencies($this->mergeParams($class, $params));
            $object = call_user_func($definition, $this, $params, $config);
        } elseif (is_array($definition)) {
            $concrete = $definition['class'];
            unset($definition['class']);
            $config = array_merge($definition, $config);
            $params = $this->mergeParams($class, $params);
            if ($concrete === $class) {
                $object = $this->build($class, $params, $config);
            } else {
                $object = $this->get($concrete, $params, $config);
            }
        } elseif (is_object($definition)) {
            return $this->_singletons[$class] = $definition;
        } else {
            throw new InvalidConfigException('Unexpected object definition type: ' . gettype($definition));
        }
        if (array_key_exists($class, $this->_singletons)) {
            // singleton
            $this->_singletons[$class] = $object;
        }
        return $object;
    }

getBehavior() public method

Defined in: yii\base\Component::getBehavior()

Returns the named behavior object.

public yii\base\Behavior|null getBehavior ( $name )
$name | string | The behavior name
return | yii\base\Behavior|null | The behavior object, or null if the behavior does not exist

Source code

                    public function getBehavior($name)
    {
        $this->ensureBehaviors();
        return isset($this->_behaviors[$name]) ? $this->_behaviors[$name] : null;
    }

getBehaviors() public method

Defined in: yii\base\Component::getBehaviors()

Returns all behaviors attached to this component.

public yii\base\Behavior[] getBehaviors ( )
return | yii\base\Behavior[] | List of behaviors attached to this component

Source code

                    public function getBehaviors()
    {
        $this->ensureBehaviors();
        return $this->_behaviors;
    }

getDefinitions() public method

Returns the list of the object definitions or the loaded shared objects.

public array getDefinitions ( )
return | array | The list of the object definitions or the loaded shared objects (type or ID => definition or instance).

Source code

                    public function getDefinitions()
    {
        return $this->_definitions;
    }

getDependencies() protected method

Returns the dependencies of the specified class.

protected array getDependencies ( $class )
$class | string | Class name, interface name or alias name
return | array | The dependencies of the specified class.
throws | yii\di\NotInstantiableException | if a dependency cannot be resolved or if a dependency cannot be fulfilled.

Source code

                    protected function getDependencies($class)
    {
        if (isset($this->_reflections[$class])) {
            return [$this->_reflections[$class], $this->_dependencies[$class]];
        }
        $dependencies = [];
        try {
            $reflection = new ReflectionClass($class);
        } catch (\ReflectionException $e) {
            throw new NotInstantiableException(
                $class,
                'Failed to instantiate component or class "' . $class . '".',
                0,
                $e
            );
        }
        $constructor = $reflection->getConstructor();
        if ($constructor !== null) {
            foreach ($constructor->getParameters() as $param) {
                if (PHP_VERSION_ID >= 50600 && $param->isVariadic()) {
                    break;
                }
                if (PHP_VERSION_ID >= 80000) {
                    $c = $param->getType();
                    $isClass = false;
                    if ($c instanceof ReflectionNamedType) {
                        $isClass = !$c->isBuiltin();
                    }
                } else {
                    try {
                        $c = $param->getClass();
                    } catch (ReflectionException $e) {
                        if (!$this->isNulledParam($param)) {
                            $notInstantiableClass = null;
                            if (PHP_VERSION_ID >= 70000) {
                                $type = $param->getType();
                                if ($type instanceof ReflectionNamedType) {
                                    $notInstantiableClass = $type->getName();
                                }
                            }
                            throw new NotInstantiableException(
                                $notInstantiableClass,
                                $notInstantiableClass === null ? 'Can not instantiate unknown class.' : null
                            );
                        } else {
                            $c = null;
                        }
                    }
                    $isClass = $c !== null;
                }
                $className = $isClass ? $c->getName() : null;
                if ($className !== null) {
                    $dependencies[$param->getName()] = Instance::of($className, $this->isNulledParam($param));
                } else {
                    $dependencies[$param->getName()] = $param->isDefaultValueAvailable()
                        ? $param->getDefaultValue()
                        : null;
                }
            }
        }
        $this->_reflections[$class] = $reflection;
        $this->_dependencies[$class] = $dependencies;
        return [$reflection, $dependencies];
    }

has() public method

Returns a value indicating whether the container has the definition of the specified name.

See also set().

public boolean has ( $class )
$class | string | Class name, interface name or alias name
return | boolean | Whether the container has the definition of the specified name.

Source code

                    public function has($class)
    {
        return isset($this->_definitions[$class]);
    }

hasEventHandlers() public method

Defined in: yii\base\Component::hasEventHandlers()

Returns a value indicating whether there is any handler attached to the named event.

public boolean hasEventHandlers ( $name )
$name | string | The event name
return | boolean | Whether there is any handler attached to the event.

Source code

                    public function hasEventHandlers($name)
    {
        $this->ensureBehaviors();
        if (!empty($this->_events[$name])) {
            return true;
        }
        foreach ($this->_eventWildcards as $wildcard => $handlers) {
            if (!empty($handlers) && StringHelper::matchWildcard($wildcard, $name)) {
                return true;
            }
        }
        return Event::hasHandlers($this, $name);
    }

hasMethod() public method

Defined in: yii\base\Component::hasMethod()

Returns a value indicating whether a method is defined.

A method is defined if:

- the class has a method with the specified name
- an attached behavior has a method with the given name (when `$checkBehaviors` is true).

public boolean hasMethod ( $name, $checkBehaviors = true )
$name | string | The property name
$checkBehaviors | boolean | Whether to treat behaviors' methods as methods of this component
return | boolean | Whether the method is defined

Source code

                    public function hasMethod($name, $checkBehaviors = true)
    {
        if (method_exists($this, $name)) {
            return true;
        } elseif ($checkBehaviors) {
            $this->ensureBehaviors();
            foreach ($this->_behaviors as $behavior) {
                if ($behavior->hasMethod($name)) {
                    return true;
                }
            }
        }
        return false;
    }

hasProperty() public method

Defined in: yii\base\Component::hasProperty()

Returns a value indicating whether a property is defined for this component.

A property is defined if:

- the class has a getter or setter method associated with the specified name (in this case, property name is case-insensitive);
- the class has a member variable with the specified name (when `$checkVars` is true);
- an attached behavior has a property of the given name (when `$checkBehaviors` is true).

See also:

- canGetProperty()
- canSetProperty()

public boolean hasProperty ( $name, $checkVars = true, $checkBehaviors = true )
$name | string | The property name
$checkVars | boolean | Whether to treat member variables as properties
$checkBehaviors | boolean | Whether to treat behaviors' properties as properties of this component
return | boolean | Whether the property is defined

Source code

                    public function hasProperty($name, $checkVars = true, $checkBehaviors = true)
    {
        return $this->canGetProperty($name, $checkVars, $checkBehaviors) || $this->canSetProperty($name, false, $checkBehaviors);
    }

hasSingleton() public method

Returns a value indicating whether the given name corresponds to a registered singleton.

public boolean hasSingleton ( $class, $checkInstance = false )
$class | string | Class name, interface name or alias name
$checkInstance | boolean | Whether to check if the singleton has been instantiated.
return | boolean | Whether the given name corresponds to a registered singleton. If `$checkInstance` is true, the method should return a value indicating whether the singleton has been instantiated.

Source code

                    public function hasSingleton($class, $checkInstance = false)
    {
        return $checkInstance ? isset($this->_singletons[$class]) : array_key_exists($class, $this->_singletons);
    }

init() public method

Defined in: yii\base\BaseObject::init()

Initializes the object.

This method is invoked at the end of the constructor after the object is initialized with the given configuration.

public void init ( )

Source code

                    public function init()
    {
    }

invoke() public method (available since version 2.0.7)

Invoke a callback with resolving dependencies in parameters.

This method allows invoking a callback and let type hinted parameter names to be resolved as objects of the Container. It additionally allows calling function using named parameters.

For example, the following callback may be invoked using the Container to resolve the formatter dependency:

    $formatString = function($string, \yii\i18n\Formatter $formatter) {
       // ...
    }
    Yii::$container->invoke($formatString, ['string' => 'Hello World!']);

This will pass the string `'Hello World!'` as the first param, and a formatter instance created by the DI container as the second param to the callable.

public mixed invoke ( callable $callback, $params = [] )
$callback | callable | Callable to be invoked.
$params | array | The array of parameters for the function. This can be either a list of parameters, or an associative array representing named function parameters.
return | mixed | The callback return value.
throws | yii\base\InvalidConfigException | if a dependency cannot be resolved or if a dependency cannot be fulfilled.
throws | yii\di\NotInstantiableException | If resolved to an abstract class or an interface (since 2.0.9)

Source code

                    public function invoke(callable $callback, $params = [])
    {
        return call_user_func_array($callback, $this->resolveCallableDependencies($callback, $params));
    }

mergeParams() protected method

Merges the user-specified constructor parameters with the ones registered via set().

protected array mergeParams ( $class, $params )
$class | string | Class name, interface name or alias name
$params | array | The constructor parameters
return | array | The merged parameters

Source code

                    protected function mergeParams($class, $params)
    {
        if (empty($this->_params[$class])) {
            return $params;
        } elseif (empty($params)) {
            return $this->_params[$class];
        }
        $ps = $this->_params[$class];
        foreach ($params as $index => $value) {
            $ps[$index] = $value;
        }
        return $ps;
    }

normalizeDefinition() protected method

Normalizes the class definition.

protected array normalizeDefinition ( $class, $definition )
$class | string | Class name
$definition | string|array|callable | The class definition
return | array | The normalized class definition
throws | yii\base\InvalidConfigException | if the definition is invalid.

Source code

                    protected function normalizeDefinition($class, $definition)
    {
        if (empty($definition)) {
            return ['class' => $class];
        } elseif (is_string($definition)) {
            return ['class' => $definition];
        } elseif ($definition instanceof Instance) {
            return ['class' => $definition->id];
        } elseif (is_callable($definition, true) || is_object($definition)) {
            return $definition;
        } elseif (is_array($definition)) {
            if (!isset($definition['class']) && isset($definition['__class'])) {
                $definition['class'] = $definition['__class'];
                unset($definition['__class']);
            }
            if (!isset($definition['class'])) {
                if (strpos($class, '\\') !== false) {
                    $definition['class'] = $class;
                } else {
                    throw new InvalidConfigException('A class definition requires a "class" member.');
                }
            }
            return $definition;
        }
        throw new InvalidConfigException("Unsupported definition type for \"$class\": " . gettype($definition));
    }

off() public method

Defined in: yii\base\Component::off()

Detaches an existing event handler from this component.

This method is the opposite of on().

Note: in case wildcard pattern is passed for event name, only the handlers registered with this wildcard will be removed, while handlers registered with plain names matching this wildcard will remain.

See also on().

public boolean off ( $name, $handler = null )
$name | string | Event name
$handler | callable|null | The event handler to be removed. If it is null, all handlers attached to the named event will be removed.
return | boolean | If a handler is found and detached

Source code

                    public function off($name, $handler = null)
    {
        $this->ensureBehaviors();
        if (empty($this->_events[$name]) && empty($this->_eventWildcards[$name])) {
            return false;
        }
        if ($handler === null) {
            unset($this->_events[$name], $this->_eventWildcards[$name]);
            return true;
        }
        $removed = false;
        // plain event names
        if (isset($this->_events[$name])) {
            foreach ($this->_events[$name] as $i => $event) {
                if ($event[0] === $handler) {
                    unset($this->_events[$name][$i]);
                    $removed = true;
                }
            }
            if ($removed) {
                $this->_events[$name] = array_values($this->_events[$name]);
                return true;
            }
        }
        // wildcard event names
        if (isset($this->_eventWildcards[$name])) {
            foreach ($this->_eventWildcards[$name] as $i => $event) {
                if ($event[0] === $handler) {
                    unset($this->_eventWildcards[$name][$i]);
                    $removed = true;
                }
            }
            if ($removed) {
                $this->_eventWildcards[$name] = array_values($this->_eventWildcards[$name]);
                // remove empty wildcards to save future redundant regex checks:
                if (empty($this->_eventWildcards[$name])) {
                    unset($this->_eventWildcards[$name]);
                }
            }
        }
        return $removed;
    }

on() public method

Defined in: yii\base\Component::on()

Attaches an event handler to an event.

The event handler must be a valid PHP callback. The following are some examples:

    function ($event) { ... }         // anonymous function
    [$object, 'handleClick']          // $object->handleClick()
    ['Page', 'handleClick']           // Page::handleClick()
    'handleClick'                     // global function handleClick()

The event handler must be defined with the following signature,

    function ($event)

where `$event` is an yii\base\Event object which includes parameters associated with the event.

Since 2.0.14 you can specify event name as a wildcard pattern:

    $component->on('event.group.*', function ($event) {
        Yii::trace($event->name . ' is triggered.');
    });

See also off().

public void on ( $name, $handler, $data = null, $append = true )
$name | string | The event name
$handler | callable | The event handler
$data | mixed | The data to be passed to the event handler when the event is triggered. When the event handler is invoked, this data can be accessed via yii\base\Event::$data.
$append | boolean | Whether to append new event handler to the end of the existing handler list. If false, the new handler will be inserted at the beginning of the existing handler list.

Source code

                    public function on($name, $handler, $data = null, $append = true)
    {
        $this->ensureBehaviors();
        if (strpos($name, '*') !== false) {
            if ($append || empty($this->_eventWildcards[$name])) {
                $this->_eventWildcards[$name][] = [$handler, $data];
            } else {
                array_unshift($this->_eventWildcards[$name], [$handler, $data]);
            }
            return;
        }
        if ($append || empty($this->_events[$name])) {
            $this->_events[$name][] = [$handler, $data];
        } else {
            array_unshift($this->_events[$name], [$handler, $data]);
        }
    }

resolveCallableDependencies() public method (available since version 2.0.7)

Resolve dependencies for a function.

This method can be used to implement similar functionality as provided by invoke() in other components.

public array resolveCallableDependencies ( callable $callback, $params = [] )
$callback | callable | Callable to be invoked.
$params | array | The array of parameters for the function, can be either numeric or associative.
return | array | The resolved dependencies.
throws | yii\base\InvalidConfigException | if a dependency cannot be resolved or if a dependency cannot be fulfilled.
throws | yii\di\NotInstantiableException | If resolved to an abstract class or an interface (since 2.0.9)

Source code

                    public function resolveCallableDependencies(callable $callback, $params = [])
    {
        if (is_array($callback)) {
            $reflection = new \ReflectionMethod($callback[0], $callback[1]);
        } elseif (is_object($callback) && !$callback instanceof \Closure) {
            $reflection = new \ReflectionMethod($callback, '__invoke');
        } else {
            $reflection = new \ReflectionFunction($callback);
        }
        $args = [];
        $associative = ArrayHelper::isAssociative($params);
        foreach ($reflection->getParameters() as $param) {
            $name = $param->getName();
            if (PHP_VERSION_ID >= 80000) {
                $class = $param->getType();
                if ($class instanceof \ReflectionUnionType || (PHP_VERSION_ID >= 80100 && $class instanceof \ReflectionIntersectionType)) {
                    $isClass = false;
                    foreach ($class->getTypes() as $type) {
                        if (!$type->isBuiltin()) {
                            $class = $type;
                            $isClass = true;
                            break;
                        }
                    }
                } else {
                    $isClass = $class !== null && !$class->isBuiltin();
                }
            } else {
                $class = $param->getClass();
                $isClass = $class !== null;
            }
            if ($isClass) {
                $className = $class->getName();
                if (PHP_VERSION_ID >= 50600 && $param->isVariadic()) {
                    $args = array_merge($args, array_values($params));
                    break;
                }
                if ($associative && isset($params[$name]) && $params[$name] instanceof $className) {
                    $args[] = $params[$name];
                    unset($params[$name]);
                } elseif (!$associative && isset($params[0]) && $params[0] instanceof $className) {
                    $args[] = array_shift($params);
                } elseif (isset(Yii::$app) && Yii::$app->has($name) && ($obj = Yii::$app->get($name)) instanceof $className) {
                    $args[] = $obj;
                } else {
                    // If the argument is optional we catch not instantiable exceptions
                    try {
                        $args[] = $this->get($className);
                    } catch (NotInstantiableException $e) {
                        if ($param->isDefaultValueAvailable()) {
                            $args[] = $param->getDefaultValue();
                        } else {
                            throw $e;
                        }
                    }
                }
            } elseif ($associative && isset($params[$name])) {
                $args[] = $params[$name];
                unset($params[$name]);
            } elseif (!$associative && count($params)) {
                $args[] = array_shift($params);
            } elseif ($param->isDefaultValueAvailable()) {
                $args[] = $param->getDefaultValue();
            } elseif (!$param->isOptional()) {
                $funcName = $reflection->getName();
                throw new InvalidConfigException("Missing required parameter \"$name\" when calling \"$funcName\".");
            }
        }
        foreach ($params as $value) {
            $args[] = $value;
        }
        return $args;
    }

resolveDependencies() protected method

Resolves dependencies by replacing them with the actual object instances.

protected array resolveDependencies ( $dependencies, $reflection = null )
$dependencies | array | The dependencies
$reflection | ReflectionClass|null | The class reflection associated with the dependencies
return | array | The resolved dependencies
throws | yii\base\InvalidConfigException | if a dependency cannot be resolved or if a dependency cannot be fulfilled.

Source code

                    protected function resolveDependencies($dependencies, $reflection = null)
    {
        foreach ($dependencies as $index => $dependency) {
            if ($dependency instanceof Instance) {
                if ($dependency->id !== null) {
                    $dependencies[$index] = $dependency->get($this);
                } elseif ($reflection !== null) {
                    $name = $reflection->getConstructor()->getParameters()[$index]->getName();
                    $class = $reflection->getName();
                    throw new InvalidConfigException("Missing required parameter \"$name\" when instantiating \"$class\".");
                }
            } elseif ($this->_resolveArrays && is_array($dependency)) {
                $dependencies[$index] = $this->resolveDependencies($dependency, $reflection);
            }
        }
        return $dependencies;
    }

set() public method

Registers a class definition with this container.

For example,

    // register a class name as is. This can be skipped.
    $container->set('yii\db\Connection');

    // register an interface
    // When a class depends on the interface, the corresponding class
    // will be instantiated as the dependent object
    $container->set('yii\mail\MailInterface', 'yii\swiftmailer\Mailer');

    // register an alias name. You can use $container->get('foo')
    // to create an instance of Connection
    $container->set('foo', 'yii\db\Connection');

    // register a class with configuration. The configuration
    // will be applied when the class is instantiated by get()
    $container->set('yii\db\Connection', [
        'dsn' => 'mysql:host=127.0.0.1;dbname=demo',
        'username' => 'root',
        'password' => '',
        'charset' => 'utf8',
    ]);

    // register an alias name with class configuration
    // In this case, a "class" element is required to specify the class
    $container->set('db', [
        'class' => 'yii\db\Connection',
        'dsn' => 'mysql:host=127.0.0.1;dbname=demo',
        'username' => 'root',
        'password' => '',
        'charset' => 'utf8',
    ]);

    // register a PHP callable
    // The callable will be executed when $container->get('db') is called
    $container->set('db', function ($container, $params, $config) {
        return new \yii\db\Connection($config);
    });

If a class definition with the same name already exists, it will be overwritten with the new one. You may use has() to check if a class definition already exists.

public $this set ( $class, $definition = [], array $params = [] )
$class | string | Class name, interface name or alias name

$definition

mixed

The definition associated with `$class`. It can be one of the following:

- a PHP callable: The callable will be executed when get() is invoked. The signature of the callable should be `function ($container, $params, $config)`, where `$params` stands for the list of constructor parameters, `$config` the object configuration, and `$container` the container object. The return value of the callable will be returned by get() as the object instance requested.
- a configuration array: the array contains name-value pairs that will be used to initialize the property values of the newly created object when get() is called. The `class` element stands for the class of the object to be created. If `class` is not specified, `$class` will be used as the class name.
- a string: a class name, an interface name or an alias name.

$params | array | The list of constructor parameters. The parameters will be passed to the class constructor when get() is called.
return | $this | The container itself

Source code

                    public function set($class, $definition = [], array $params = [])
    {
        $this->_definitions[$class] = $this->normalizeDefinition($class, $definition);
        $this->_params[$class] = $params;
        unset($this->_singletons[$class]);
        return $this;
    }

setDefinitions() public method (available since version 2.0.11)

Registers class definitions within this container.

See also set() to know more about possible values of definitions.

public void setDefinitions ( array $definitions )

$definitions

array

Array of definitions. There are two allowed formats of array. The first format:

- key: class name, interface name or alias name. The key will be passed to the set() method as a first argument `$class`.
- value: the definition associated with `$class`. Possible values are described in set() documentation for the `$definition` parameter. Will be passed to the set() method as the second argument `$definition`.

Example: ```php $container->setDefinitions([

    'yii\web\Request' => 'app\components\Request',
    'yii\web\Response' => [
        'class' => 'app\components\Response',
        'format' => 'json'
    ],
    'foo\Bar' => function () {
        $qux = new Qux;
        $foo = new Foo($qux);
        return new Bar($foo);
    }

]); ```

The second format:

- key: class name, interface name or alias name. The key will be passed to the set() method as a first argument `$class`.
- value: array of two elements. The first element will be passed the set() method as the second argument `$definition`, the second one — as `$params`.

Example: ```php $container->setDefinitions([

    'foo\Bar' => [
         ['class' => 'app\Bar'],
         [Instance::of('baz')]
     ]

]); ```

Source code

                    public function setDefinitions(array $definitions)
    {
        foreach ($definitions as $class => $definition) {
            if (is_array($definition) && count($definition) === 2 && array_values($definition) === $definition && is_array($definition[1])) {
                $this->set($class, $definition[0], $definition[1]);
                continue;
            }
            $this->set($class, $definition);
        }
    }

setResolveArrays() public method (available since version 2.0.37)

public void setResolveArrays ( $value )
$value | boolean | Whether to attempt to resolve elements in array dependencies

Source code

                    public function setResolveArrays($value)
    {
        $this->_resolveArrays = (bool) $value;
    }

setSingleton() public method

Registers a class definition with this container and marks the class as a singleton class.

This method is similar to set() except that classes registered via this method will only have one instance. Each time get() is called, the same instance of the specified class will be returned.

See also set().

public $this setSingleton ( $class, $definition = [], array $params = [] )
$class | string | Class name, interface name or alias name
$definition | mixed | The definition associated with `$class`. See set() for more details.
$params | array | The list of constructor parameters. The parameters will be passed to the class constructor when get() is called.
return | $this | The container itself

Source code

                    public function setSingleton($class, $definition = [], array $params = [])
    {
        $this->_definitions[$class] = $this->normalizeDefinition($class, $definition);
        $this->_params[$class] = $params;
        $this->_singletons[$class] = null;
        return $this;
    }

setSingletons() public method (available since version 2.0.11)

Registers class definitions as singletons within this container by calling setSingleton().

See also:

- setDefinitions() for allowed formats of $singletons parameter.
- setSingleton() to know more about possible values of definitions.

public void setSingletons ( array $singletons )
$singletons | array | Array of singleton definitions. See setDefinitions() for allowed formats of array.

Source code

                    public function setSingletons(array $singletons)
    {
        foreach ($singletons as $class => $definition) {
            if (is_array($definition) && count($definition) === 2 && array_values($definition) === $definition) {
                $this->setSingleton($class, $definition[0], $definition[1]);
                continue;
            }
            $this->setSingleton($class, $definition);
        }
    }

trigger() public method

Defined in: yii\base\Component::trigger()

Triggers an event.

This method represents the happening of an event. It invokes all attached handlers for the event including class-level handlers.

public void trigger ( $name, yii\base\Event $event = null )
$name | string | The event name
$event | yii\base\Event|null | The event instance. If not set, a default yii\base\Event object will be created.

Source code

                    public function trigger($name, Event $event = null)
    {
        $this->ensureBehaviors();
        $eventHandlers = [];
        foreach ($this->_eventWildcards as $wildcard => $handlers) {
            if (StringHelper::matchWildcard($wildcard, $name)) {
                $eventHandlers[] = $handlers;
            }
        }
        if (!empty($this->_events[$name])) {
            $eventHandlers[] = $this->_events[$name];
        }
        if (!empty($eventHandlers)) {
            $eventHandlers = call_user_func_array('array_merge', $eventHandlers);
            if ($event === null) {
                $event = new Event();
            }
            if ($event->sender === null) {
                $event->sender = $this;
            }
            $event->handled = false;
            $event->name = $name;
            foreach ($eventHandlers as $handler) {
                $event->data = $handler[1];
                call_user_func($handler[0], $event);
                // stop further handling if the event is handled
                if ($event->handled) {
                    return;
                }
            }
        }
        // invoke class-level attached handlers
        Event::trigger($this, $name, $event);
    }