PHP7 TemplateMethod

Behavioral/TemplateMethod/Journey.php

@@ -4,6 +4,11 @@ namespace DesignPatterns\Behavioral\TemplateMethod;
 
 abstract class Journey
 {
+    /**
+     * @var string[]
+     */
+    private $thingsToDo = [];
+
     /**
      * This is the public service provided by this class and its subclasses.
      * Notice it is final to "freeze" the global behavior of algorithm.
@@ -12,46 +17,49 @@ abstract class Journey
      */
     final public function takeATrip()
     {
-        $this->buyAFlight();
-        $this->takePlane();
-        $this->enjoyVacation();
-        $this->buyGift();
-        $this->takePlane();
+        $this->thingsToDo[] = $this->buyAFlight();
+        $this->thingsToDo[] = $this->takePlane();
+        $this->thingsToDo[] = $this->enjoyVacation();
+        $buyGift = $this->buyGift();
+
+        if ($buyGift !== null) {
+            $this->thingsToDo[] = $buyGift;
+        }
+
+        $this->thingsToDo[] = $this->takePlane();
     }
 
     /**
      * This method must be implemented, this is the key-feature of this pattern.
      */
-    abstract protected function enjoyVacation();
+    abstract protected function enjoyVacation(): string;
 
     /**
      * This method is also part of the algorithm but it is optional.
-     * This is an "adapter" (do not confuse with the Adapter pattern, not related)
-     * You can override it only if you need to.
+     * You can override it only if you need to
+     *
+     * @return null|string
      */
     protected function buyGift()
     {
+        return null;
+    }
+
+    private function buyAFlight(): string
+    {
+        return 'Buy a flight ticket';
+    }
+
+    private function takePlane(): string
+    {
+        return 'Taking the plane';
     }
 
     /**
-     * This method will be unknown by subclasses (better).
+     * @return string[]
      */
-    private function buyAFlight()
+    public function getThingsToDo(): array
     {
-        echo "Buying a flight\n";
+        return $this->thingsToDo;
     }
-
-    /**
-     * Subclasses will get access to this method but cannot override it and
-     * compromise this algorithm (warning : cause of cyclic dependencies).
-     */
-    final protected function takePlane()
-    {
-        echo "Taking the plane\n";
-    }
-
-    // A note regarding the keyword "final" : don't use it when you start coding :
-    // add it after you narrow and know exactly what change and what remain unchanged
-    // in this algorithm.
-    // [abstract] x [3 access] x [final] = 12 combinations, it can be hard !
 }