added registry pattern

Registry/Registry.php

@@ -0,0 +1,51 @@
+<?php
+
+namespace DesignPatterns;
+
+/**
+ * Registry pattern
+ *
+ * Purpose:
+ * to implement a central storage for objects often used throughout the application, is typically implemented using
+ * an abstract class with only static methods (or using the Singleton pattern)
+ *
+ * Example:
+ * - Zend Framework: Zend_Registry holds the application's logger object, front controller etc.
+ *
+ */
+
+abstract class Registry
+{
+    const LOGGER = 'logger';
+
+    protected static $_storedValues;
+
+    /**
+     * @static
+     * @param string $key
+     * @param mixed $value
+     * @return void
+     */
+    public static function set($key, $value)
+    {
+        self::$_storedValues[$key] = $value;
+    }
+
+    /**
+     * @static
+     * @param string $key
+     * @return mixed
+     */
+    public static function get($key)
+    {
+        return self::$_storedValues[$key];
+    }
+
+    // typically there would be methods to check if a key has already been registered and so on ...
+}
+
+// while bootstraping the application
+Registry::set(Registry::LOGGER, new StdClass());
+
+// throughout the application
+Registry::get(Registry::LOGGER)->log('foo');