refactored code to use Instance::ensure()

extensions/gii/generators/model/Generator.php

@@ -437,7 +437,7 @@ class Generator extends \yii\gii\Generator
      */
     public function validateDb()
     {
-        if (Yii::$app->hasComponent($this->db) === false) {
+        if (!Yii::$app->has($this->db)) {
             $this->addError('db', 'There is no application component named "db".');
         } elseif (!Yii::$app->get($this->db) instanceof Connection) {
             $this->addError('db', 'The "db" application component must be a DB connection instance.');

extensions/mongodb/Cache.php

@@ -9,6 +9,7 @@ namespace yii\mongodb;
 
 use Yii;
 use yii\base\InvalidConfigException;
+use yii\di\Instance;
 
 /**
  * Cache implements a cache application component by storing cached data in a MongoDB.
@@ -61,12 +62,7 @@ class Cache extends \yii\caching\Cache
     public function init()
     {
         parent::init();
-        if (is_string($this->db)) {
-            $this->db = Yii::$app->get($this->db);
-        }
-        if (!$this->db instanceof Connection) {
-            throw new InvalidConfigException($this->className() . "::db must be either a MongoDB connection instance or the application component ID of a MongoDB connection.");
-        }
+        $this->db = Instance::ensure($this->db, Connection::className());
     }
 
     /**

extensions/mongodb/Session.php

@@ -9,6 +9,7 @@ namespace yii\mongodb;
 
 use Yii;
 use yii\base\InvalidConfigException;
+use yii\di\Instance;
 
 /**
  * Session extends [[\yii\web\Session]] by using MongoDB as session data storage.
@@ -55,13 +56,8 @@ class Session extends \yii\web\Session
      */
     public function init()
     {
-        if (is_string($this->db)) {
-            $this->db = Yii::$app->get($this->db);
-        }
-        if (!$this->db instanceof Connection) {
-            throw new InvalidConfigException($this->className() . "::db must be either a MongoDB connection instance or the application component ID of a MongoDB connection.");
-        }
         parent::init();
+        $this->db = Instance::ensure($this->db, Connection::className());
     }
 
     /**

extensions/sphinx/Schema.php

@@ -132,7 +132,7 @@ class Schema extends Object
 
         if ($db->enableSchemaCache && !in_array($name, $db->schemaCacheExclude, true)) {
             /** @var $cache Cache */
-            $cache = is_string($db->schemaCache) ? Yii::$app->get($db->schemaCache) : $db->schemaCache;
+            $cache = is_string($db->schemaCache) ? Yii::$app->get($db->schemaCache, false) : $db->schemaCache;
             if ($cache instanceof Cache) {
                 $key = $this->getCacheKey($name);
                 if ($refresh || ($index = $cache->get($key)) === false) {
@@ -296,7 +296,7 @@ class Schema extends Object
     public function refresh()
     {
         /** @var $cache Cache */
-        $cache = is_string($this->db->schemaCache) ? Yii::$app->get($this->db->schemaCache) : $this->db->schemaCache;
+        $cache = is_string($this->db->schemaCache) ? Yii::$app->get($this->db->schemaCache, false) : $this->db->schemaCache;
         if ($this->db->enableSchemaCache && $cache instanceof Cache) {
             GroupDependency::invalidate($cache, $this->getCacheGroup());
         }

framework/caching/DbCache.php

@@ -11,6 +11,7 @@ use Yii;
 use yii\base\InvalidConfigException;
 use yii\db\Connection;
 use yii\db\Query;
+use yii\di\Instance;
 
 /**
  * DbCache implements a cache application component by storing cached data in a database.
@@ -79,12 +80,7 @@ class DbCache extends Cache
     public function init()
     {
         parent::init();
-        if (is_string($this->db)) {
-            $this->db = Yii::$app->get($this->db);
-        }
-        if (!$this->db instanceof Connection) {
-            throw new InvalidConfigException("DbCache::db must be either a DB connection instance or the application component ID of a DB connection.");
-        }
+        $this->db = Instance::ensure($this->db, Connection::className());
     }
 
     /**

framework/caching/DbDependency.php

@@ -10,6 +10,7 @@ namespace yii\caching;
 use Yii;
 use yii\base\InvalidConfigException;
 use yii\db\Connection;
+use yii\di\Instance;
 
 /**
  * DbDependency represents a dependency based on the query result of a SQL statement.
@@ -45,10 +46,7 @@ class DbDependency extends Dependency
      */
     protected function generateDependencyData($cache)
     {
-        $db = Yii::$app->get($this->db);
-        if (!$db instanceof Connection) {
-            throw new InvalidConfigException("DbDependency::db must be the application component ID of a DB connection.");
-        }
+        $db = Instance::ensure($this->db, Connection::className());
         if ($this->sql === null) {
             throw new InvalidConfigException("DbDependency::sql must be set.");
         }

framework/console/controllers/CacheController.php

@@ -53,7 +53,7 @@ class CacheController extends Controller
     public function actionFlush($component = 'cache')
     {
         /** @var Cache $cache */
-        $cache = Yii::$app->get($component);
+        $cache = Yii::$app->get($component, false);
         if (!$cache || !$cache instanceof Cache) {
             throw new Exception('Application component "'.$component.'" is not defined or not a cache.');
         }

framework/data/ActiveDataProvider.php

@@ -13,6 +13,7 @@ use yii\base\InvalidConfigException;
 use yii\base\Model;
 use yii\db\Connection;
 use yii\db\QueryInterface;
+use yii\di\Instance;
 
 /**
  * ActiveDataProvider implements a data provider based on [[\yii\db\Query]] and [[\yii\db\ActiveQuery]].
@@ -85,10 +86,7 @@ class ActiveDataProvider extends BaseDataProvider
     {
         parent::init();
         if (is_string($this->db)) {
-            $this->db = Yii::$app->get($this->db);
-            if ($this->db === null) {
-                throw new InvalidConfigException('The "db" property must be a valid DB Connection application component.');
-            }
+            $this->db = Instance::ensure($this->db, Connection::className());
         }
     }
 

framework/data/SqlDataProvider.php

@@ -10,6 +10,7 @@ namespace yii\data;
 use Yii;
 use yii\base\InvalidConfigException;
 use yii\db\Connection;
+use yii\di\Instance;
 
 /**
  * SqlDataProvider implements a data provider based on a plain SQL statement.
@@ -89,12 +90,7 @@ class SqlDataProvider extends BaseDataProvider
     public function init()
     {
         parent::init();
-        if (is_string($this->db)) {
-            $this->db = Yii::$app->get($this->db);
-        }
-        if (!$this->db instanceof Connection) {
-            throw new InvalidConfigException('The "db" property must be a valid DB Connection application component.');
-        }
+        $this->db = Instance::ensure($this->db, Connection::className());
         if ($this->sql === null) {
             throw new InvalidConfigException('The "sql" property must be set.');
         }

framework/db/Command.php

@@ -378,7 +378,7 @@ class Command extends \yii\base\Component
 
         /** @var \yii\caching\Cache $cache */
         if ($db->enableQueryCache && $method !== '') {
-            $cache = is_string($db->queryCache) ? Yii::$app->get($db->queryCache) : $db->queryCache;
+            $cache = is_string($db->queryCache) ? Yii::$app->get($db->queryCache, false) : $db->queryCache;
         }
 
         if (isset($cache) && $cache instanceof Cache) {

framework/db/Migration.php

@@ -6,6 +6,7 @@
  */
 
 namespace yii\db;
+use yii\di\Instance;
 
 /**
  * Migration is the base class for representing a database migration.
@@ -36,10 +37,10 @@ namespace yii\db;
 class Migration extends \yii\base\Component
 {
     /**
-     * @var Connection the database connection that this migration should work with.
-     * If not set, it will be initialized as the 'db' application component.
+     * @var Connection|string the DB connection object or the application component ID of the DB connection
+     * that this migration should work with.
      */
-    public $db;
+    public $db = 'db';
 
     /**
      * Initializes the migration.
@@ -48,9 +49,7 @@ class Migration extends \yii\base\Component
     public function init()
     {
         parent::init();
-        if ($this->db === null) {
-            $this->db = \Yii::$app->get('db');
-        }
+        $this->db = Instance::ensure($this->db, Connection::className());
     }
 
     /**

framework/db/Schema.php

@@ -96,7 +96,7 @@ abstract class Schema extends Object
 
         if ($db->enableSchemaCache && !in_array($name, $db->schemaCacheExclude, true)) {
             /** @var Cache $cache */
-            $cache = is_string($db->schemaCache) ? Yii::$app->get($db->schemaCache) : $db->schemaCache;
+            $cache = is_string($db->schemaCache) ? Yii::$app->get($db->schemaCache, false) : $db->schemaCache;
             if ($cache instanceof Cache) {
                 $key = $this->getCacheKey($name);
                 if ($refresh || ($table = $cache->get($key)) === false) {
@@ -225,7 +225,7 @@ abstract class Schema extends Object
     public function refresh()
     {
         /** @var Cache $cache */
-        $cache = is_string($this->db->schemaCache) ? Yii::$app->get($this->db->schemaCache) : $this->db->schemaCache;
+        $cache = is_string($this->db->schemaCache) ? Yii::$app->get($this->db->schemaCache, false) : $this->db->schemaCache;
         if ($this->db->enableSchemaCache && $cache instanceof Cache) {
             GroupDependency::invalidate($cache, $this->getCacheGroup());
         }

framework/di/ContainerInterface.php

@@ -61,13 +61,14 @@ interface ContainerInterface
      * If a component is not shared, this method will create a new instance every time.
      *
      * @param string $typeOrID component type (a fully qualified namespaced class/interface name, e.g. `yii\db\Connection`) or ID (e.g. `db`).
+     * @param boolean $throwException whether to throw an exception if `$typeOrID` is not registered with the container before.
      * @return object the component of the specified type or ID
      * @throws \yii\base\InvalidConfigException if `$typeOrID` refers to a nonexistent component ID
      * or if there is cyclic dependency detected
      * @see has()
      * @see set()
      */
-    public function get($typeOrID);
+    public function get($typeOrID, $throwException = true);
 
     /**
      * Registers a component definition with this container.

framework/di/ContainerTrait.php

@@ -63,24 +63,36 @@ trait ContainerTrait
      *
      * @param string $typeOrID component type (a fully qualified namespaced class/interface name, e.g. `yii\db\Connection`)
      * or ID (e.g. `db`). When a class/interface name is given, make sure it does NOT have a leading backslash.
-     * @return object the component of the specified type or ID
+     * @param boolean $throwException whether to throw an exception if `$typeOrID` is not registered with the container before.
+     * @return object|null the component of the specified type or ID. If `$throwException` is false and `$typeOrID`
+     * is not registered before, null will be returned.
      * @throws InvalidConfigException if `$typeOrID` refers to a nonexistent component ID
      * or if there is cyclic dependency detected
      * @see has()
      * @see set()
      */
-    public function get($typeOrID)
+    public function get($typeOrID, $throwException = true)
     {
         if (isset($this->_components[$typeOrID])) {
             return $this->_components[$typeOrID];
         }
 
+        if (!isset($this->_definitions[$typeOrID])) {
+            if (strpos($typeOrID, '\\') !== false) {
+                // a class name
+                return $this->buildComponent($typeOrID);
+            } elseif (!$throwException) {
+                return null;
+            } else {
+                throw new InvalidConfigException("Unknown component ID: $typeOrID");
+            }
+        }
+
         if (isset($this->_building[$typeOrID])) {
             throw new InvalidConfigException("A cyclic dependency of \"$typeOrID\" is detected.");
         }
 
         $this->_building[$typeOrID] = true;
-        if (isset($this->_definitions[$typeOrID])) {
         $definition = $this->_definitions[$typeOrID];
         if (is_string($definition)) {
             // a type or ID
@@ -95,12 +107,6 @@ trait ContainerTrait
             // a configuration array
             $component = $this->buildComponent($definition);
         }
-        } elseif (strpos($typeOrID, '\\') !== false) {
-            // a class name
-            $component = $this->buildComponent($typeOrID);
-        } else {
-            throw new InvalidConfigException("Unknown component ID: $typeOrID");
-        }
         unset($this->_building[$typeOrID]);
 
         if (array_key_exists($typeOrID, $this->_components)) {

framework/di/Instance.php

@@ -82,7 +82,7 @@ class Instance
      */
     public static function of($id, ContainerInterface $container = null)
     {
-        return new self($id, $container);
+        return new static($id, $container);
     }
 
     /**
@@ -108,7 +108,7 @@ class Instance
      * You may specify a reference in terms of a component ID or an Instance object.
      * @param string $type the class name to be checked
      * @param ContainerInterface $container the container. If null, the application instance will be used.
-     * @return null|\yii\base\Component|Instance
+     * @return object
      * @throws \yii\base\InvalidConfigException
      */
     public static function ensure($value, $type, $container = null)
@@ -119,7 +119,7 @@ class Instance
         if ($value instanceof $type) {
             return $value;
         } elseif (is_string($value)) {
-            $value = new self($value, $container);
+            $value = new static($value, $container);
         }
 
         if ($value instanceof self) {

framework/i18n/DbMessageSource.php

@@ -9,6 +9,7 @@ namespace yii\i18n;
 
 use Yii;
 use yii\base\InvalidConfigException;
+use yii\di\Instance;
 use yii\helpers\ArrayHelper;
 use yii\caching\Cache;
 use yii\db\Connection;
@@ -93,19 +94,9 @@ class DbMessageSource extends MessageSource
     public function init()
     {
         parent::init();
-        if (is_string($this->db)) {
-            $this->db = Yii::$app->get($this->db);
-        }
-        if (!$this->db instanceof Connection) {
-            throw new InvalidConfigException("DbMessageSource::db must be either a DB connection instance or the application component ID of a DB connection.");
-        }
+        $this->db = Instance::ensure($this->db, Connection::className());
         if ($this->enableCaching) {
-            if (is_string($this->cache)) {
-                $this->cache = Yii::$app->get($this->cache);
-            }
-            if (!$this->cache instanceof Cache) {
-                throw new InvalidConfigException("DbMessageSource::cache must be either a cache object or the application component ID of the cache object.");
-            }
+            $this->cache = Instance::ensure($this->cache, Cache::className());
         }
     }
 

framework/log/DbTarget.php

@@ -10,6 +10,7 @@ namespace yii\log;
 use Yii;
 use yii\db\Connection;
 use yii\base\InvalidConfigException;
+use yii\di\Instance;
 
 /**
  * DbTarget stores log messages in a database table.
@@ -62,12 +63,7 @@ class DbTarget extends Target
     public function init()
     {
         parent::init();
-        if (is_string($this->db)) {
-            $this->db = Yii::$app->get($this->db);
-        }
-        if (!$this->db instanceof Connection) {
-            throw new InvalidConfigException("DbTarget::db must be either a DB connection instance or the application component ID of a DB connection.");
-        }
+        $this->db = Instance::ensure($this->db, Connection::className());
     }
 
     /**

framework/log/EmailTarget.php

@@ -9,6 +9,7 @@ namespace yii\log;
 
 use Yii;
 use yii\base\InvalidConfigException;
+use yii\di\Instance;
 use yii\mail\MailerInterface;
 
 /**
@@ -43,12 +44,7 @@ class EmailTarget extends Target
         if (empty($this->message['to'])) {
             throw new InvalidConfigException('The "to" option must be set for EmailTarget::message.');
         }
-        if (is_string($this->mail)) {
-            $this->mail = Yii::$app->get($this->mail);
-        }
-        if (!$this->mail instanceof MailerInterface) {
-            throw new InvalidConfigException("EmailTarget::mailer must be either a mailer object or the application component ID of a mailer object.");
-        }
+        $this->mail = Instance::ensure($this->mail, 'yii\mail\MailerInterface');
     }
 
     /**

framework/mutex/DbMutex.php

@@ -10,6 +10,7 @@ namespace yii\mutex;
 use Yii;
 use yii\db\Connection;
 use yii\base\InvalidConfigException;
+use yii\di\Instance;
 
 /**
  * @author resurtm <resurtm@gmail.com>
@@ -31,11 +32,6 @@ abstract class DbMutex extends Mutex
     public function init()
     {
         parent::init();
-        if (is_string($this->db)) {
-            $this->db = Yii::$app->get($this->db);
-        }
-        if (!$this->db instanceof Connection) {
-            throw new InvalidConfigException('Mutex::db must be either a DB connection instance or the application component ID of a DB connection.');
-        }
+        $this->db = Instance::ensure($this->db, Connection::className());
     }
 }

framework/rbac/DbManager.php

@@ -15,6 +15,7 @@ use yii\base\Exception;
 use yii\base\InvalidConfigException;
 use yii\base\InvalidCallException;
 use yii\base\InvalidParamException;
+use yii\di\Instance;
 
 /**
  * DbManager represents an authorization manager that stores authorization information in database.
@@ -59,14 +60,9 @@ class DbManager extends Manager
      */
     public function init()
     {
-        if (is_string($this->db)) {
-            $this->db = Yii::$app->get($this->db);
-        }
-        if (!$this->db instanceof Connection) {
-            throw new InvalidConfigException("DbManager::db must be either a DB connection instance or the application component ID of a DB connection.");
-        }
-        $this->_usingSqlite = !strncmp($this->db->getDriverName(), 'sqlite', 6);
         parent::init();
+        $this->db = Instance::ensure($this->db, Connection::className());
+        $this->_usingSqlite = !strncmp($this->db->getDriverName(), 'sqlite', 6);
     }
 
     /**

framework/test/DbFixture.php

@@ -10,6 +10,8 @@ namespace yii\test;
 use Yii;
 use yii\base\InvalidConfigException;
 use yii\db\Connection;
+use yii\di\Instance;
+use yii\base\Object;
 
 /**
  * DbFixture is the base class for DB-related fixtures.
@@ -34,11 +36,6 @@ abstract class DbFixture extends Fixture
     public function init()
     {
         parent::init();
-        if (is_string($this->db)) {
-            $this->db = Yii::$app->get($this->db);
-        }
-        if (!is_object($this->db)) {
-            throw new InvalidConfigException("The 'db' property must be either a DB connection instance or the application component ID of a DB connection.");
-        }
+        $this->db = Instance::ensure($this->db, Object::className());
     }
 }

framework/web/CacheSession.php

@@ -10,6 +10,7 @@ namespace yii\web;
 use Yii;
 use yii\caching\Cache;
 use yii\base\InvalidConfigException;
+use yii\di\Instance;
 
 /**
  * CacheSession implements a session component using cache as storage medium.
@@ -52,13 +53,8 @@ class CacheSession extends Session
      */
     public function init()
     {
-        if (is_string($this->cache)) {
-            $this->cache = Yii::$app->get($this->cache);
-        }
-        if (!$this->cache instanceof Cache) {
-            throw new InvalidConfigException('CacheSession::cache must refer to the application component ID of a cache object.');
-        }
         parent::init();
+        $this->cache = Instance::ensure($this->cache, Cache::className());
     }
 
     /**

framework/web/DbSession.php

@@ -11,6 +11,7 @@ use Yii;
 use yii\db\Connection;
 use yii\db\Query;
 use yii\base\InvalidConfigException;
+use yii\di\Instance;
 
 /**
  * DbSession extends [[Session]] by using database as session data storage.
@@ -74,13 +75,8 @@ class DbSession extends Session
      */
     public function init()
     {
-        if (is_string($this->db)) {
-            $this->db = Yii::$app->get($this->db);
-        }
-        if (!$this->db instanceof Connection) {
-            throw new InvalidConfigException("DbSession::db must be either a DB connection instance or the application component ID of a DB connection.");
-        }
         parent::init();
+        $this->db = Instance::ensure($this->db, Connection::className());
     }
 
     /**

framework/web/UrlManager.php

@@ -145,7 +145,7 @@ class UrlManager extends Component
             return;
         }
         if (is_string($this->cache)) {
-            $this->cache = Yii::$app->get($this->cache);
+            $this->cache = Yii::$app->get($this->cache, false);
         }
         if ($this->cache instanceof Cache) {
             $key = __CLASS__;

framework/widgets/FragmentCache.php

@@ -11,6 +11,7 @@ use Yii;
 use yii\base\Widget;
 use yii\caching\Cache;
 use yii\caching\Dependency;
+use yii\di\Instance;
 
 /**
  *
@@ -79,11 +80,7 @@ class FragmentCache extends Widget
     {
         parent::init();
 
-        if (!$this->enabled) {
-            $this->cache = null;
-        } elseif (is_string($this->cache)) {
-            $this->cache = Yii::$app->get($this->cache);
-        }
+        $this->cache = $this->enabled ? Instance::ensure($this->cache, Cache::className()) : null;
 
         if ($this->getCachedContent() === false) {
             $this->getView()->cacheStack[] = $this;