Added example of preference to Zend\Di Examples

example-20.php

@@ -0,0 +1,37 @@
+<?php
+
+namespace MovieApp {
+    class Lister {
+        public $finder;
+        public function setFinder(FinderInterface $finder){
+            $this->finder = $finder;
+        }
+    }
+
+    class DbFinder implements FinderInterface{
+    }
+
+    interface FinderInterface {
+    }
+}
+
+namespace {
+    // bootstrap
+    include 'zf2bootstrap' . ((stream_resolve_include_path('zf2bootstrap.php')) ? '.php' : '.dist.php');
+
+    $di = new Zend\Di\Di;
+    $di->configure(new Zend\Di\Configuration(array(
+        'instance' => array(
+            'preferences' => array(
+                'MovieApp\FinderInterface' => 'MovieApp\DbFinder'
+            )
+        )
+    )));
+    $lister = $di->get('MovieApp\Lister');
+
+    // expression to test
+    $works = ($lister->finder instanceof MovieApp\DbFinder);
+
+    // display result
+    echo (($works) ? 'It works!' : 'It DOES NOT work!') . PHP_EOL;
+}