php傳入對象時獲得類型提示

類的類型提示 - 將類名放在需要約束的方法參數之前

語法格式：

public function write(ShopProduct $shopProduct){}

數組提示：

public function setArray(array $storearray){}

class ShopProduct{
    public $title = 'default product';      // 屬性也稱為成員變量，用來存放對象之間互不相同的數據
    public $producerMainName = 'main name';
    public $producerFirstName = 'first name';
    public $price = 0;

    // 創建對象時，構造方法會被自動調用，構造方法可以確保必要的屬性設置，並完成任何需要准備的工作
    public function __construct($title,$producerMainName,$producerFirstName,$price){
        $this->title = $title;      // 使用偽變量$this給每個變量賦值
        $this->producerMainName = $producerMainName;
        $this->producerFirstName = $producerFirstName;
        $this->price = $price;
    }

    public function getProducer(){  // 方法讓對象執行任務
        return $this->producerMainName . $this->producerFirstName;
    }
}

class ShopProductWriter{
    public function write(ShopProduct $shopProduct){    // 類的類型提示，只需將類名放在需要約束的方法參數之前
        $str = $shopProduct->title . ':' . $shopProduct->getProducer() . "($shopProduct->price) . </br>";
        print $str;
    }

    public function setArray(array $storearray){        // 數組提示
        var_dump($storearray);
    }

    public function setWriter(ObjectWriter $objectWriter=null){
        var_dump($objectWriter);
    }
}

class Wrong{};
$store = array('name'=>'taobao');
$objectWriter = NULL;

$product1 = new ShopProduct('My Antonia','Willa','Cather',5.99);    // 更易於實例化，也更安全，實例化和設置只需要一條語句就可以完成，任何使用ShopProduct對象的代碼都可以相信所有的屬性皆被初始化了
$writer = new ShopProductWriter();
$writer->write($product1);        // 有了參數提示，規定此處只能傳入new ShopProduct對象
$writer->write(new Wrong());     // 傳入其它的對象會出現：Catchable fatal error: Argument 1 passed to ShopProductWriter::write() must be an instance of ShopProduct, instance of Wrong given..從而防止隱藏bug的產生。
$writer->setArray($store);        // 有了參數提示，規定此處只能傳入一個數組
$writer->setWriter($objectWriter); // 有了參數提示，規定此處只能傳入NULL