cs DependencyInjection

DependencyInjection/Connection.php

@@ -0,0 +1,35 @@
+<?php
+
+namespace DesignPatterns\DependencyInjection;
+
+/**
+ * Class Connection
+ */
+class Connection
+{
+    /**
+     * @var Configuration
+     */
+    protected $configuration;
+
+    /**
+     * here, Configuration gets injected and Connection will get all that it needs from Configuration
+     * without DI, the configuration would be created directly in Connection, which is not very good
+     * for testing and extending Connection
+     *
+     * @param Configuration $config
+     */
+    public function __construct(Configuration $config)
+    {
+        $this->configuration = $config;
+    }
+
+    /**
+     * connection using the injected config
+     */
+    public function connect()
+    {
+        $host = $this->configuration->getHost();
+        // ...
+    }
+}