added abstract factory and factory pattern

FactoryMethod/FactoryMethod.php

@@ -0,0 +1,49 @@
+<?php
+
+namespace DesignPatterns;
+
+/**
+ * Factory Method pattern
+ *
+ * Purpose:
+ * similar to the AbstractFactory, this pattern is used to create series of related or dependant objects.
+ * The difference between this and the abstract factory pattern is that the factory method pattern uses just one static
+ * method to create all types of objects it can create. It is usually named "factory" or "build".
+ *
+ * Examples:
+ * - Zend Framework: Zend_Cache_Backend or _Frontend use a factory method create cache backends or frontends
+ * 
+ */
+class FactoryMethod
+{
+    /**
+     * the parametrized function to get create an instance
+     *
+     * @static
+     * @return Format
+     */
+    public static function factory($type)
+    {
+        $className = 'Format' . ucfirst($type);
+        if ( ! class_exists($className)) {
+            throw new Exception('Missing format class.');
+        }
+
+        return new $className();
+    }
+}
+
+interface Formatter
+{
+
+}
+
+class FormatString implements Formatter
+{
+
+}
+
+class FormatNumber implements Formatter
+{
+    
+}