Class yii\di\Instance
Inheritance | yii\di\Instance |
---|---|
Available since version | 2.0 |
Source Code | https://github.com/yiisoft/yii2/blob/master/framework/di/Instance.php |
Instance represents a reference to a named object in a dependency injection (DI) container or a service locator.
You may use get() to obtain the actual object referenced by $id.
Instance is mainly used in two places:
- When configuring a dependency injection container, you use Instance to reference a class name, interface name or alias name. The reference can later be resolved into the actual object by the container.
- In classes which use service locator to obtain dependent objects.
The following example shows how to configure a DI container with Instance:
$container = new \yii\di\Container;
$container->set('cache', [
'class' => 'yii\caching\DbCache',
'db' => Instance::of('db')
]);
$container->set('db', [
'class' => 'yii\db\Connection',
'dsn' => 'sqlite:path/to/file.db',
]);
And the following example shows how a class retrieves a component from a service locator:
class DbCache extends Cache
{
public $db = 'db';
public function init()
{
parent::init();
$this->db = Instance::ensure($this->db, 'yii\db\Connection');
}
}
Public Properties
Property | Type | Description | Defined By |
---|---|---|---|
$id | string | The component ID, class name, interface name or alias name | yii\di\Instance |
$optional | boolean | If null should be returned instead of throwing an exception | yii\di\Instance |
Public Methods
Method | Description | Defined By |
---|---|---|
__set_state() | Restores class state after using var_export() . |
yii\di\Instance |
ensure() | Resolves the specified reference into the actual object and makes sure it is of the specified type. | yii\di\Instance |
get() | Returns the actual object referenced by this Instance object. | yii\di\Instance |
of() | Creates a new Instance object. | yii\di\Instance |
Protected Methods
Method | Description | Defined By |
---|---|---|
__construct() | Constructor. | yii\di\Instance |
Property Details
The component ID, class name, interface name or alias name
Method Details
Constructor.
protected void __construct ( $id, $optional = false ) | ||
$id | string |
The component ID |
$optional | boolean |
If null should be returned instead of throwing an exception |
protected function __construct($id, $optional = false)
{
$this->id = $id;
$this->optional = $optional;
}
Restores class state after using var_export()
.
See also https://www.php.net/manual/en/function.var-export.php.
public static yii\di\Instance __set_state ( $state ) | ||
$state | array | |
throws | yii\base\InvalidConfigException |
when $state property does not contain |
---|
public static function __set_state($state)
{
if (!isset($state['id'])) {
throw new InvalidConfigException('Failed to instantiate class "Instance". Required parameter "id" is missing');
}
return new self($state['id']);
}
Resolves the specified reference into the actual object and makes sure it is of the specified type.
The reference may be specified as a string or an Instance object. If the former, it will be treated as a component ID, a class/interface name or an alias, depending on the container type.
If you do not specify a container, the method will first try Yii::$app
followed by Yii::$container
.
For example,
use yii\db\Connection;
// returns Yii::$app->db
$db = Instance::ensure('db', Connection::class);
// returns an instance of Connection using the given configuration
$db = Instance::ensure(['dsn' => 'sqlite:path/to/my.db'], Connection::class);
public static object ensure ( $reference, $type = null, $container = null ) | ||
$reference | object|string|array|static |
An object or a reference to the desired object.
You may specify a reference in terms of a component ID or an Instance object.
Starting from version 2.0.2, you may also pass in a configuration array for creating the object.
If the "class" value is not specified in the configuration array, it will use the value of |
$type | string|null |
The class/interface name to be checked. If null, type check will not be performed. |
$container | yii\di\ServiceLocator|yii\di\Container|null |
The container. This will be passed to get(). |
return | object |
The object referenced by the Instance, or |
---|---|---|
throws | yii\base\InvalidConfigException |
if the reference is invalid |
public static function ensure($reference, $type = null, $container = null)
{
if (is_array($reference)) {
$class = isset($reference['class']) ? $reference['class'] : $type;
if (!$container instanceof Container) {
$container = Yii::$container;
}
unset($reference['class']);
$component = $container->get($class, [], $reference);
if ($type === null || $component instanceof $type) {
return $component;
}
throw new InvalidConfigException('Invalid data type: ' . $class . '. ' . $type . ' is expected.');
} elseif (empty($reference)) {
throw new InvalidConfigException('The required component is not specified.');
}
if (is_string($reference)) {
$reference = new static($reference);
} elseif ($type === null || $reference instanceof $type) {
return $reference;
}
if ($reference instanceof self) {
try {
$component = $reference->get($container);
} catch (\ReflectionException $e) {
throw new InvalidConfigException('Failed to instantiate component or class "' . $reference->id . '".', 0, $e);
}
if ($type === null || $component instanceof $type) {
return $component;
}
throw new InvalidConfigException('"' . $reference->id . '" refers to a ' . get_class($component) . " component. $type is expected.");
}
$valueType = is_object($reference) ? get_class($reference) : gettype($reference);
throw new InvalidConfigException("Invalid data type: $valueType. $type is expected.");
}
Returns the actual object referenced by this Instance object.
public object get ( $container = null ) | ||
$container | yii\di\ServiceLocator|yii\di\Container|null |
The container used to locate the referenced object.
If null, the method will first try |
return | object |
The actual object referenced by this Instance object. |
---|
public function get($container = null)
{
try {
if ($container) {
return $container->get($this->id);
}
if (Yii::$app && Yii::$app->has($this->id)) {
return Yii::$app->get($this->id);
}
return Yii::$container->get($this->id);
} catch (\Exception $e) {
if ($this->optional) {
return null;
}
throw $e;
} catch (\Throwable $e) {
if ($this->optional) {
return null;
}
throw $e;
}
}
Creates a new Instance object.
public static yii\di\Instance of ( $id, $optional = false ) | ||
$id | string |
The component ID |
$optional | boolean |
If null should be returned instead of throwing an exception |
return | yii\di\Instance |
The new Instance object. |
---|
public static function of($id, $optional = false)
{
return new static($id, $optional);
}
Signup or Login in order to comment.