PHP7 Dependency Injection

Structural/DependencyInjection/DatabaseConnection.php

@@ -0,0 +1,34 @@
+<?php
+
+namespace DesignPatterns\Structural\DependencyInjection;
+
+class DatabaseConnection
+{
+    /**
+     * @var DatabaseConfiguration
+     */
+    private $configuration;
+
+    /**
+     * @param DatabaseConfiguration $config
+     */
+    public function __construct(DatabaseConfiguration $config)
+    {
+        $this->configuration = $config;
+    }
+
+    public function getDsn(): string
+    {
+        // this is just for the sake of demonstration, not a real DSN
+        // notice that only the injected config is used here, so there is
+        // a real separation of concerns here
+
+        return sprintf(
+            '%s:%s@%s:%d',
+            $this->configuration->getUsername(),
+            $this->configuration->getPassword(),
+            $this->configuration->getHost(),
+            $this->configuration->getPort()
+        );
+    }
+}