cs Strategy

Strategy/index.php

@@ -0,0 +1,39 @@
+<?php
+
+namespace DesignPatterns\Strategy;
+
+/**
+ * strategy pattern
+ *
+ * Terminology:
+ * - Context
+ * - Strategy
+ * - Concrete Strategy
+ *
+ * Purpose:
+ * to separate strategies and to enable fast switching between them.
+ * also this pattern is a good alternative to inheritance (instead of having an abstract class that is extended)
+ *
+ * Examples:
+ * - sorting a list of objects, one strategy by date, the other by id
+ * - simplify unit testing: e.g. switching between file and in-memory storage
+ *
+ */
+
+$elements = array(
+    array(
+        'id' => 2,
+        'date' => '2011-01-01',
+    ),
+    array(
+        'id' => 1,
+        'date' => '2011-02-01'
+    )
+);
+
+$collection = new ObjectCollection($elements);
+$collection->setComparator(new IdComparator());
+$collection->sort();
+
+$collection->setComparator(new DateComparator());
+$collection->sort();