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157 lines
5.4 KiB
157 lines
5.4 KiB
<?php |
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/** |
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* @link http://www.yiiframework.com/ |
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* @copyright Copyright (c) 2008 Yii Software LLC |
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* @license http://www.yiiframework.com/license/ |
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*/ |
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namespace yii\di; |
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use Yii; |
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use yii\base\InvalidConfigException; |
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/** |
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* Instance represents a reference to a named object in a dependency injection (DI) container or a service locator. |
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* |
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* You may use [[get()]] to obtain the actual object referenced by [[id]]. |
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* |
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* Instance is mainly used in two places: |
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* |
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* - When configuring a dependency injection container, you use Instance to reference a class name, interface name |
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* or alias name. The reference can later be resolved into the actual object by the container. |
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* - In classes which use service locator to obtain dependent objects. |
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* |
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* The following example shows how to configure a DI container with Instance: |
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* |
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* ```php |
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* $container = new \yii\di\Container; |
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* $container->set('cache', 'yii\caching\DbCache', Instance::of('db')); |
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* $container->set('db', [ |
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* 'class' => 'yii\db\Connection', |
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* 'dsn' => 'sqlite:path/to/file.db', |
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* ]); |
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* ``` |
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* |
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* And the following example shows how a class retrieves a component from a service locator: |
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* |
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* ```php |
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* class DbCache extends Cache |
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* { |
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* public $db = 'db'; |
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* |
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* public function init() |
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* { |
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* parent::init(); |
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* $this->db = Instance::ensure($this->db, 'yii\db\Connection'); |
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* } |
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* } |
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* ``` |
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* |
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* @author Qiang Xue <qiang.xue@gmail.com> |
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* @since 2.0 |
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*/ |
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class Instance |
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{ |
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/** |
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* @var string the component ID, class name, interface name or alias name |
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*/ |
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public $id; |
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/** |
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* Constructor. |
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* @param string $id the component ID |
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*/ |
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protected function __construct($id) |
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{ |
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$this->id = $id; |
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} |
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/** |
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* Creates a new Instance object. |
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* @param string $id the component ID |
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* @return Instance the new Instance object. |
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*/ |
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public static function of($id) |
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{ |
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return new static($id); |
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} |
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/** |
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* Resolves the specified reference into the actual object and makes sure it is of the specified type. |
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* |
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* The reference may be specified as a string or an Instance object. If the former, |
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* it will be treated as a component ID, a class/interface name or an alias, depending on the container type. |
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* |
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* If you do not specify a container, the method will first try `Yii::$app` followed by `Yii::$container`. |
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* |
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* For example, |
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* |
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* ```php |
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* use yii\db\Connection; |
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* |
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* // returns Yii::$app->db |
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* $db = Instance::ensure('db', Connection::className()); |
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* // returns an instance of Connection using the given configuration |
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* $db = Instance::ensure(['dsn' => 'sqlite:path/to/my.db'], Connection::className()); |
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* ``` |
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* |
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* @param object|string|array|static $reference an object or a reference to the desired object. |
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* You may specify a reference in terms of a component ID or an Instance object. |
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* Starting from version 2.0.2, you may also pass in a configuration array for creating the object. |
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* If the "class" value is not specified in the configuration array, it will use the value of `$type`. |
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* @param string $type the class/interface name to be checked. If null, type check will not be performed. |
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* @param ServiceLocator|Container $container the container. This will be passed to [[get()]]. |
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* @return object the object referenced by the Instance, or `$reference` itself if it is an object. |
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* @throws InvalidConfigException if the reference is invalid |
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*/ |
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public static function ensure($reference, $type = null, $container = null) |
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{ |
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if (is_array($reference)) { |
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$class = isset($reference['class']) ? $reference['class'] : $type; |
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if (!$container instanceof Container) { |
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$container = Yii::$container; |
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} |
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unset($reference['class']); |
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return $container->get($class, [], $reference); |
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} elseif (empty($reference)) { |
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throw new InvalidConfigException('The required component is not specified.'); |
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} |
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if (is_string($reference)) { |
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$reference = new static($reference); |
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} elseif ($type === null || $reference instanceof $type) { |
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return $reference; |
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} |
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if ($reference instanceof self) { |
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$component = $reference->get($container); |
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if ($type === null || $component instanceof $type) { |
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return $component; |
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} else { |
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throw new InvalidConfigException('"' . $reference->id . '" refers to a ' . get_class($component) . " component. $type is expected."); |
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} |
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} |
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$valueType = is_object($reference) ? get_class($reference) : gettype($reference); |
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throw new InvalidConfigException("Invalid data type: $valueType. $type is expected."); |
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} |
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/** |
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* Returns the actual object referenced by this Instance object. |
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* @param ServiceLocator|Container $container the container used to locate the referenced object. |
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* If null, the method will first try `Yii::$app` then `Yii::$container`. |
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* @return object the actual object referenced by this Instance object. |
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*/ |
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public function get($container = null) |
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{ |
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if ($container) { |
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return $container->get($this->id); |
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} |
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if (Yii::$app && Yii::$app->has($this->id)) { |
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return Yii::$app->get($this->id); |
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} else { |
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return Yii::$container->get($this->id); |
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} |
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} |
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}
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