Allow loading of an external container (#19)

* Allow loading of an external container

* Update README.md

README.md

@@ -297,7 +297,19 @@ Database::transaction(function () use ($car) {
 
 ## Dependency Injection
 
-The orm does a very simple way of dependency injection. When a instance of a model is created is created
+You can provide your own `ContainerInterface` to `DependencyManager`, this container will be used for everything. You still need to provide the container with instances of `Database`, `DatabaseAdmin` and `OrmMemcache`.
+
+```php
+$container = $kernel->getContainer();
+
+DependencyManager::setContainer($container);
+
+$container->set(OrmMemcache::class, new OrmMemcache($cachePath));
+$container->set(Database::class, new Database($pdo));
+$container->set(DatabaseAdmin::class, new DatabaseAdmin($pdo));
+```
+
+It is also possible to leverage the dependency injection provided by the orm. The orm does a very simple way of dependency injection. When a instance of a model is created is created
 it tries to lookup any dependencies which extend `DependencyManager` if they are found they are wired into the
 model and available for use. There can only be one version of a model and this is kept track of in `DependencyManager`.
 

composer.json

@@ -23,7 +23,8 @@
   "license": "MIT",
   "require": {
     "php": ">=7.0.27",
-    "zumba/json-serializer": "^2.2",
+		"psr/container": "^1.0",
+		"zumba/json-serializer": "^2.2",
 		"ext-pdo": "*",
 		"ext-json": "*"
 	},

src/DependencyManager.php

@@ -2,6 +2,7 @@
 namespace CsrDelft\Orm;
 
 use CsrDelft\Orm\Exception\CsrOrmException;
+use Psr\Container\ContainerInterface;
 
 /**
  * Any class extending this class is able to be autoloaded.
@@ -31,13 +32,22 @@ abstract class DependencyManager {
 	 */
 	private static $loading = [];
 
+	/**
+	 * @var ContainerInterface|null
+	 */
+	protected static $container = null;
+
 	/**
 	 * Static constructor. Can be implemented in base classes.
 	 */
 	public static function __static() {
 		// Empty.
 	}
 
+	public static function setContainer(ContainerInterface $container) {
+		static::$container = $container;
+	}
+
 	/**
 	 * Used to initialize a Singleton if needed.
 	 *
@@ -71,6 +81,10 @@ public static function addDependency($dependency) {
 	 * @return static
 	 */
 	final public static function instance() {
+		if (static::$container && static::$container->has(static::class)) {
+			return static::$container->get(static::class);
+		}
+
 		if (!isset(self::$instance[static::class])) {
 			self::$instance[static::class] = static::init();
 		}