新增 狀態模式 State Pattern

Kantai235 · Kantai235 · commit 95b72607be06 · 2020-10-07T16:34:48.000+08:00
diff --git a/DesignPatterns/Behavioral/README.md b/DesignPatterns/Behavioral/README.md
@@ -25,7 +25,7 @@
 規格模式，將邏輯條件給抽離出來，獨立成一個模組，而不是在物件內透過邏輯判斷來撰寫複雜的程式碼，簡化物件所需要實踐的邏輯，物件可以套用一個規則，也可以套用多種規則，就像大頭菜本身的價格運算是一種規格，過期後的價格運算又是另一種規格，可以把這個價格運算的邏輯抽離出來獨立成模組。
 
 ## [狀態模式 State Pattern](/DesignPatterns/Behavioral/StatePattern)
-
+狀態模式，讓物件的狀態改變時，一同改變物件的行為模式，就像是大頭菜(Turnips)這個物件，有沒有壞掉只是一個狀態(State)來辨別，但如果壞掉了，那麼會因為狀態改變的關係，而讓大頭菜計算鈴錢價格的方式也跟著改變。
 
 ## [策略模式 Strategy Pattern](/DesignPatterns/Behavioral/StrategyPattern)
 
diff --git a/DesignPatterns/Behavioral/StatePattern/README.md b/DesignPatterns/Behavioral/StatePattern/README.md
@@ -1,15 +1,201 @@
 ![Banner](https://raw.githubusercontent.com/Kantai235/php-design-pattern/master/DesignPatterns/Behavioral/StatePattern/Banner.png)
 
 # 狀態模式 State Pattern
+狀態模式，讓物件的狀態改變時，一同改變物件的行為模式，就像是大頭菜(Turnips)這個物件，有沒有壞掉只是一個狀態(State)來辨別，但如果壞掉了，那麼會因為狀態改變的關係，而讓大頭菜計算鈴錢價格的方式也跟著改變。
 
 ## UML
 ![UML](https://raw.githubusercontent.com/Kantai235/php-design-pattern/master/DesignPatterns/Behavioral/StatePattern/UML.png)
 
 ## 實作
+因為要讓大頭菜(Turnips)掛載狀態物件，所以我們要先來定義狀態，會需要提供進入到下個狀態的方法，以及 `toString` 來查看當前的狀態是什麼。
 
+State.php
+```php
+/**
+ * Interface State.
+ */
+interface State
+{
+    /**
+     * @param Turnips $turnips
+     */
+    public function proceedToNext(Turnips $turnips);
+
+    /**
+     * @return string
+     */
+    public function toString(): string;
+}
+```
+
+首先是大頭菜剛建立出來的狀態，而大頭菜下個狀態是壞掉的狀態，所以在 `proceedToNext` 方法我們要將大頭菜(Turnips)來去賦予下個階段的狀態。
+
+StateCreated.php
+```php
+/**
+ * Class StateCreated.
+ */
+class StateCreated implements State
+{
+    /**
+     * @param Turnips $turnips
+     */
+    public function proceedToNext(Turnips $turnips)
+    {
+        $turnips->setState(new StateSpoiled());
+    }
+
+    /**
+     * @return string
+     */
+    public function toString(): string
+    {
+        return 'created';
+    }
+}
+```
+
+再來是壞掉的大頭菜狀態，這個階段已經是最終階段了，所以在 `proceedToNext` 的部分則是不實作任何事。
+
+StateSpoiled.php
+```php
+/**
+ * Class StateSpoiled.
+ */
+class StateSpoiled implements State
+{
+    /**
+     * @param Turnips $turnips
+     */
+    public function proceedToNext(Turnips $turnips)
+    {
+        // there is nothing more to do
+    }
+
+    /**
+     * @return string
+     */
+    public function toString(): string
+    {
+        return 'spoiled';
+    }
+}
+```
+
+最後我們要實作大頭菜(Turnips)，除了要儲存鈴錢價格(Price)、數量(Count)以外，還要儲存當前的狀態(State)，這個狀態會在一開始被建立時就擁有，並且會在執行 `proceedToNext` 時被變更，最後提供計算鈴錢總價格的 `calculatePrice` 方法，並且根據當前的狀態(State)來切換計算模式。
+
+Turnips.php
+```php
+/**
+ * Class Turnips.
+ */
+class Turnips
+{
+    /**
+     * @var State
+     */
+    protected State $state;
+
+    /**
+     * @var int
+     */
+    protected int $price;
+
+    /**
+     * @var int
+     */
+    protected int $count;
+
+    /**
+     * Turnips constructor.
+     * 
+     * @param int $price
+     * @param int $count
+     */
+    public function __construct(int $price, int $count)
+    {
+        $this->price = $price;
+        $this->count = $count;
+    }
+
+    /**
+     * @return Turnips
+     */
+    public static function create(int $price, int $count): Turnips
+    {
+        $turnips = new self($price, $count);
+        $turnips->state = new StateCreated();
+
+        return $turnips;
+    }
+
+    /**
+     * @param State $state
+     */
+    public function setState(State $state)
+    {
+        $this->state = $state;
+    }
+
+    /**
+     * @return void
+     */
+    public function proceedToNext()
+    {
+        $this->state->proceedToNext($this);
+    }
+
+    /**
+     * @return string
+     */
+    public function toString()
+    {
+        return $this->state->toString();
+    }
+
+    /**
+     * @return int
+     */
+    public function calculatePrice(): int
+    {
+        switch ($this->toString()) {
+            case 'created':
+                return $this->price * $this->count;
+
+            case 'spoiled':
+                return 0;
+        }
+    }
+}
+```
 
 ## 測試
+最後我們要對狀態模式做測試，測試的項目很簡單，就是建立一個大頭菜物件，這時候是健康的大頭菜，所以應該要可以得知大頭菜現在的狀態是剛建立的 `created` 以及正常計算鈴錢價格，再來把大頭菜切換為下個狀態，也就是壞掉的大頭菜，這時候應該要獲得壞掉的狀態 `spoiled` 以及計算出 0 鈴錢。
+
+StatePatternTest.php
+```php
+/**
+ * Class StatePatternTest.
+ */
+class StatePatternTest extends TestCase
+{
+    /**
+     * @test
+     */
+    public function test_state_spoiled()
+    {
+        $turnips = Turnips::create(100, 40);
 
+        $this->assertSame('created', $turnips->toString());
+        $this->assertEquals(4000, $turnips->calculatePrice());
+
+        $turnips->proceedToNext();
+
+        $this->assertSame('spoiled', $turnips->toString());
+        $this->assertEquals(0, $turnips->calculatePrice());
+    }
+}
+```
 
 最後測試的執行結果會獲得如下：
 
@@ -20,6 +206,15 @@ PHPUnit Pretty Result Printer 0.28.0 by Codedungeon and contributors.
 PHPUnit 9.2.6 by Sebastian Bergmann and contributors.
 
 
+ ==> ...fResponsibilitiesTest   ✔  ✔  ✔  
+ ==> CommandPatternTest         ✔  
+ ==> IteratorPatternTest        ✔  ✔  ✔  ✔  
+ ==> MediatorPatternTest        ✔  ✔  ✔  
+ ==> MementoPatternTest         ✔  
+ ==> NullObjectPatternTest      ✔  ✔  ✔  ✔  
+ ==> ObserverPatternTest        ✔  
+ ==> SpecificationPatternTest   ✔  ✔  ✔  ✔  
+ ==> StatePatternTest           ✔  
  ==> AbstractFactoryTest        ✔  ✔  ✔  ✔  
  ==> BuilderPatternTest         ✔  ✔  ✔  ✔  
  ==> FactoryMethodTest          ✔  ✔  ✔  ✔  
@@ -40,9 +235,9 @@ PHPUnit 9.2.6 by Sebastian Bergmann and contributors.
  ==> ProxyPatternTest           ✔  ✔  
  ==> RegistryPatternTest        ✔  ✔  ✔  ✔  ✔  
 
-Time: 00:00.037, Memory: 6.00 MB
+Time: 00:00.100, Memory: 8.00 MB
 
-OK (51 tests, 116 assertions)
+OK (73 tests, 145 assertions)
 ```
 
 ## 完整程式碼
diff --git a/DesignPatterns/Behavioral/StatePattern/State.php b/DesignPatterns/Behavioral/StatePattern/State.php
@@ -0,0 +1,19 @@
+<?php
+
+namespace DesignPatterns\Behavioral\StatePattern;
+
+/**
+ * Interface State.
+ */
+interface State
+{
+    /**
+     * @param Turnips $turnips
+     */
+    public function proceedToNext(Turnips $turnips);
+
+    /**
+     * @return string
+     */
+    public function toString(): string;
+}
diff --git a/DesignPatterns/Behavioral/StatePattern/StateCreated.php b/DesignPatterns/Behavioral/StatePattern/StateCreated.php
@@ -0,0 +1,25 @@
+<?php
+
+namespace DesignPatterns\Behavioral\StatePattern;
+
+/**
+ * Class StateCreated.
+ */
+class StateCreated implements State
+{
+    /**
+     * @param Turnips $turnips
+     */
+    public function proceedToNext(Turnips $turnips)
+    {
+        $turnips->setState(new StateSpoiled());
+    }
+
+    /**
+     * @return string
+     */
+    public function toString(): string
+    {
+        return 'created';
+    }
+}
diff --git a/DesignPatterns/Behavioral/StatePattern/StateSpoiled.php b/DesignPatterns/Behavioral/StatePattern/StateSpoiled.php
@@ -0,0 +1,25 @@
+<?php
+
+namespace DesignPatterns\Behavioral\StatePattern;
+
+/**
+ * Class StateSpoiled.
+ */
+class StateSpoiled implements State
+{
+    /**
+     * @param Turnips $turnips
+     */
+    public function proceedToNext(Turnips $turnips)
+    {
+        // there is nothing more to do
+    }
+
+    /**
+     * @return string
+     */
+    public function toString(): string
+    {
+        return 'spoiled';
+    }
+}
diff --git a/DesignPatterns/Behavioral/StatePattern/Turnips.php b/DesignPatterns/Behavioral/StatePattern/Turnips.php
@@ -0,0 +1,85 @@
+<?php
+
+namespace DesignPatterns\Behavioral\StatePattern;
+
+/**
+ * Class Turnips.
+ */
+class Turnips
+{
+    /**
+     * @var State
+     */
+    protected State $state;
+
+    /**
+     * @var int
+     */
+    protected int $price;
+
+    /**
+     * @var int
+     */
+    protected int $count;
+
+    /**
+     * Turnips constructor.
+     * 
+     * @param int $price
+     * @param int $count
+     */
+    public function __construct(int $price, int $count)
+    {
+        $this->price = $price;
+        $this->count = $count;
+    }
+
+    /**
+     * @return Turnips
+     */
+    public static function create(int $price, int $count): Turnips
+    {
+        $turnips = new self($price, $count);
+        $turnips->state = new StateCreated();
+
+        return $turnips;
+    }
+
+    /**
+     * @param State $state
+     */
+    public function setState(State $state)
+    {
+        $this->state = $state;
+    }
+
+    /**
+     * @return void
+     */
+    public function proceedToNext()
+    {
+        $this->state->proceedToNext($this);
+    }
+
+    /**
+     * @return string
+     */
+    public function toString()
+    {
+        return $this->state->toString();
+    }
+
+    /**
+     * @return int
+     */
+    public function calculatePrice(): int
+    {
+        switch ($this->toString()) {
+            case 'created':
+                return $this->price * $this->count;
+
+            case 'spoiled':
+                return 0;
+        }
+    }
+}
diff --git a/DesignPatterns/Behavioral/StatePattern/UML.png b/DesignPatterns/Behavioral/StatePattern/UML.png
diff --git a/Tests/Behavioral/StatePatternTest.php b/Tests/Behavioral/StatePatternTest.php
diff --git a/UML.mdj b/UML.mdj
