refactored State pattern example

Behavioral/State/ContextOrder.php

@@ -1,26 +0,0 @@
-<?php
-
-namespace DesignPatterns\Behavioral\State;
-
-class ContextOrder extends StateOrder
-{
-    public function getState():StateOrder
-    {
-        return static::$state;
-    }
-
-    public function setState(StateOrder $state)
-    {
-        static::$state = $state;
-    }
-
-    public function done()
-    {
-        static::$state->done();
-    }
-
-    public function getStatus(): string
-    {
-        return static::$state->getStatus();
-    }
-}

Behavioral/State/CreateOrder.php

@@ -1,16 +0,0 @@
-<?php
-
-namespace DesignPatterns\Behavioral\State;
-
-class CreateOrder extends StateOrder
-{
-    public function __construct()
-    {
-        $this->setStatus('created');
-    }
-
-    protected function done()
-    {
-        static::$state = new ShippingOrder();
-    }
-}

Behavioral/State/OrderContext.php

@@ -0,0 +1,34 @@
+<?php
+
+namespace DesignPatterns\Behavioral\State;
+
+class OrderContext
+{
+    /**
+     * @var State
+     */
+    private $state;
+
+    public static function create(): OrderContext
+    {
+        $order = new self();
+        $order->state = new StateCreated();
+
+        return $order;
+    }
+
+    public function setState(State $state)
+    {
+        $this->state = $state;
+    }
+
+    public function proceedToNext()
+    {
+        $this->state->proceedToNext($this);
+    }
+
+    public function toString()
+    {
+        return $this->state->toString();
+    }
+}

Behavioral/State/README.rst

@@ -20,27 +20,33 @@ Code
 
 You can also find this code on `GitHub`_
 
-ContextOrder.php
+OrderContext.php
 
-.. literalinclude:: ContextOrder.php
+.. literalinclude:: OrderContext.php
    :language: php
    :linenos:
 
-StateOrder.php
+State.php
 
-.. literalinclude:: StateOrder.php
+.. literalinclude:: State.php
    :language: php
    :linenos:
 
-ShippingOrder.php
+StateCreated.php
 
-.. literalinclude:: ShippingOrder.php
+.. literalinclude:: StateCreated.php
    :language: php
    :linenos:
 
-CreateOrder.php
+StateShipped.php
 
-.. literalinclude:: CreateOrder.php
+.. literalinclude:: StateShipped.php
+   :language: php
+   :linenos:
+
+StateDone.php
+
+.. literalinclude:: StateDone.php
    :language: php
    :linenos:
 

Behavioral/State/ShippingOrder.php

@@ -1,16 +0,0 @@
-<?php
-
-namespace DesignPatterns\Behavioral\State;
-
-class ShippingOrder extends StateOrder
-{
-    public function __construct()
-    {
-        $this->setStatus('shipping');
-    }
-
-    protected function done()
-    {
-        $this->setStatus('completed');
-    }
-}

Behavioral/State/State.php

@@ -0,0 +1,10 @@
+<?php
+
+namespace DesignPatterns\Behavioral\State;
+
+interface State
+{
+    public function proceedToNext(OrderContext $context);
+
+    public function toString(): string;
+}

Behavioral/State/StateCreated.php

@@ -0,0 +1,16 @@
+<?php
+
+namespace DesignPatterns\Behavioral\State;
+
+class StateCreated implements State
+{
+    public function proceedToNext(OrderContext $context)
+    {
+        $context->setState(new StateShipped());
+    }
+
+    public function toString(): string
+    {
+        return 'created';
+    }
+}

Behavioral/State/StateDone.php

@@ -0,0 +1,16 @@
+<?php
+
+namespace DesignPatterns\Behavioral\State;
+
+class StateDone implements State
+{
+    public function proceedToNext(OrderContext $context)
+    {
+        // there is nothing more to do
+    }
+
+    public function toString(): string
+    {
+        return 'done';
+    }
+}

Behavioral/State/StateOrder.php

@@ -1,32 +0,0 @@
-<?php
-
-namespace DesignPatterns\Behavioral\State;
-
-abstract class StateOrder
-{
-    /**
-     * @var array
-     */
-    private $details;
-
-    /**
-     * @var StateOrder $state
-     */
-    protected static $state;
-
-    /**
-     * @return mixed
-     */
-    abstract protected function done();
-
-    protected function setStatus(string $status)
-    {
-        $this->details['status'] = $status;
-        $this->details['updatedTime'] = time();
-    }
-
-    protected function getStatus(): string
-    {
-        return $this->details['status'];
-    }
-}

Behavioral/State/StateShipped.php

@@ -0,0 +1,16 @@
+<?php
+
+namespace DesignPatterns\Behavioral\State;
+
+class StateShipped implements State
+{
+    public function proceedToNext(OrderContext $context)
+    {
+        $context->setState(new StateDone());
+    }
+
+    public function toString(): string
+    {
+        return 'shipped';
+    }
+}

Behavioral/State/Tests/StateTest.php

@@ -2,30 +2,42 @@
 
 namespace DesignPatterns\Behavioral\State\Tests;
 
-use DesignPatterns\Behavioral\State\ContextOrder;
-use DesignPatterns\Behavioral\State\CreateOrder;
+use DesignPatterns\Behavioral\State\OrderContext;
 use PHPUnit\Framework\TestCase;
 
 class StateTest extends TestCase
 {
-    public function testCanShipCreatedOrder()
+    public function testIsCreatedWithStateCreated()
     {
-        $order = new CreateOrder();
-        $contextOrder = new ContextOrder();
-        $contextOrder->setState($order);
-        $contextOrder->done();
+        $orderContext = OrderContext::create();
 
-        $this->assertEquals('shipping', $contextOrder->getStatus());
+        $this->assertEquals('created', $orderContext->toString());
     }
 
-    public function testCanCompleteShippedOrder()
+    public function testCanProceedToStateShipped()
     {
-        $order = new CreateOrder();
-        $contextOrder = new ContextOrder();
-        $contextOrder->setState($order);
-        $contextOrder->done();
-        $contextOrder->done();
+        $contextOrder = OrderContext::create();
+        $contextOrder->proceedToNext();
 
-        $this->assertEquals('completed', $contextOrder->getStatus());
+        $this->assertEquals('shipped', $contextOrder->toString());
+    }
+
+    public function testCanProceedToStateDone()
+    {
+        $contextOrder = OrderContext::create();
+        $contextOrder->proceedToNext();
+        $contextOrder->proceedToNext();
+
+        $this->assertEquals('done', $contextOrder->toString());
+    }
+
+    public function testStateDoneIsTheLastPossibleState()
+    {
+        $contextOrder = OrderContext::create();
+        $contextOrder->proceedToNext();
+        $contextOrder->proceedToNext();
+        $contextOrder->proceedToNext();
+
+        $this->assertEquals('done', $contextOrder->toString());
     }
 }